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1 The TheAirbus AirbusSafety safetyMagazine magazine July July2015 2014 #20 #18 Safety first

2 002 Safety First #20 | July 2015 Safety first, #20 July, 2015. Safety first is Safety first The Airbus magazine contributing to the enhancement published by Airbus S.A.S. - 1, rond point Maurice Bellonte - 31707 Blagnac Cedex/France. of the safety of aircraft operations by increasing knowledge Publisher: Yannick Malinge, Chief Product Safety and communication on safety related topics. Officer, Editor: Corinne Bieder, Director Product Safety Strategy & Communication. Concept Design by Airbus Multi Media Support 20151274. Reference: GS 420.0045 Issue 20. Photos by Airbus, H. Gouss, Lindner Fotografie, Safety first is published by the Product Safety depart- A. Doumenjou, P. Pigeyre, P. Masclet, B. Sveinsson, C. Brinkmann, Aneese. ment. It is a source of specialist safety information for the Printed in France. restricted use of flight and ground crew members who fly This brochure is printed on Triple Star Satin. and maintain Airbus aircraft. It is also distributed to other This paper is produced in factories that are selected organisations. accredited EMAS and certified ISO 9001-14001, PEFC and FSC CoC. It is produced using pulp that has been whitened without either chlorine Material for publication is obtained from multiple sources or acid. The paper is entirely recyclable and is and includes selected information from the Airbus Flight produced from trees grown in sustainable forest resources. Safety Confidential Reporting System, incident and acci- The printing inks use organic pigments or dent investigation reports, system tests and flight tests. minerals. There is no use of basic dyes or dangerous metals from the cadmium, lead, Material is also obtained from sources within the airline mercury or hexavalent chromium group. industry, studies and reports from government agencies and other aviation sources. All articles in Safety first are presented for information only and are not intended to replace ICAO guidelines, stand- ards or recommended practices, operator-mandated requirements or technical orders. The contents do not supersede any requirements mandated by the State of Registry of the Operators aircraft or supersede or amend Airbus S.A.S. 2015 All rights reserved. Proprietary documents. any Airbus type-specific AFM, AMM, FCOM, MMEL docu- By taking delivery of this Brochure mentation or any other approved documentation. (hereafter Brochure), you accept on behalf of your company to comply with the following Articles may be reprinted without permission, except guidelines: where copyright source is indicated, but with acknowl- No other intellectual property rights are granted by the delivery of this Brochure than the right to edgement to Airbus. Where Airbus is not the author, the read it, for the sole purpose of information. contents of the article do not necessarily reflect the views This Brochure and its content shall of Airbus, neither do they indicate Company policy. not be modified and its illustrations and photos shall not be reproduced without prior written consent of Airbus. Contributions, comment and feedback are welcome. For This Brochure and the materials it contains technical reasons the editors may be required to make shall not, in whole or in part, be sold, rented, or editorial changes to manuscripts, however every effort will licensed to any third party subject to payment. be made to preserve the intended meaning of the original. This Brochure contains sensitive information that is correct at the time of going to press. Enquiries related to this publication should be addressed to: This information involves a number of factors that could change over time, effecting the true public representation. Airbus assumes no obligation to update any information contained in this document or with respect to the information described herein. Airbus S.A.S. shall assume no liability for any Airbus damage in connection with the use of this Product Safety department (GS) Brochure and of the materials it contains, even if 1, rond point Maurice Bellonte Airbus S.A.S. has been advised of the likelihood of such damages. 31707 Blagnac Cedex - France [email protected] Fax: +33(0)5 61 93 44 29

3 editorial In the current era of wealth of data where Big Data, smart data and other data related trends emerge, a key question arises: what can data tell us, and under what conditions? Over the past decades, safety has evolved from primarily reactive approaches such as accident and incident inves- YANNICK MALINGE tigation, to more proactive approaches to try to anticipate SVP & Chief and thus prevent safety issues. In line with this evolution, Product Safety Officer there is a change of scale in the nature and the amount of data. If Big Data seems a promising complement to two other pillars of efficient safety enhancement - namely proper reporting and cascading of lessons learned - it requires some careful consideration as to how the data are collected and analysed. From statistical patterns identified to relevant safety rec- ommendations, the way is long and involves interpreta- tion, sense-making often requiring a qualitative analysis calling for a good knowledge and understanding of oper- ations and safety context. With this in mind, we must take great care with some Big Data approaches that use a variety of sources of data collected for a variety of purposes and through a generic and somehow magic algorithm come out with apparently very credible safety results. Can we confuse big with good when it comes to data? Is it reasonable to make the assumption that big amounts of data could be self- sense-making? Evolving towards more proactive approaches, better understanding of normal operations and detecting trends are keys to further enhancements in safety. However, whatever the amount of data, the experience of aviation professionals is essential to make sure they are processed and interpreted wisely.

4 002 Safety First #20 | July 2015 NEWS A statistical Analysis on Commercial Aviation Accidents: check the 2015 edition! The new edition of our yearly brochure on commercial aviation accidents sta- tistics is now available. This statistical analysis examines the evolution of hull- loss and fatal accidents during revenue flights from 1958 to 2014. A particular focus is made on a breakdown of statistics by generations of aircraft and main accident categories, namely Controlled Flight Into terrain (CFIT), Loss Of Con- trol In-flight (LOC-I) and Runway Excursion (RE). Visit our airbus.com website (keyword safety) or find it on our tablet application. SAVE THE DATE NEWS 22nd FLIGHT SAFETY CONFERENCE 2016 We are pleased to announce that the have an open dialogue to promote 22 Flight Safety Conference will take flight safety across the fleet, we are place in Bangkok, Thailand, from the unable to accept outside parties. 21 to the 24 of March 2016. The for- mal invitations with information regard- As always, we welcome presentations ing registration and logistics, as well as from our operators. You can partic- the preliminary agenda will be sent to ipate as a speaker and share your our customers in January 2016. ideas and experience for improving For any information regarding invita- aviation safety. tions, please contact Mrs. Nuria Soler, If you have something you believe email [email protected] will benefit other operators and/or Air- bus and if you are interested in being The Flight Safety Conference provides a speaker, please provide us with a an excellent forum for the exchange brief abstract and a bio or resume at of information between Airbus and [email protected] its customers. To ensure that we can

5 22nd Flight Safety Conference Bangkok, 21-24 March 2016

6 004 Safety First #20 | July 2015

7 Safety First #18 | July 2014 005 Safety first #20 PROCEDURES P06 Control your speed... during climb P14 Lateral runway excursions upon landing OPERATIONS P28 Fuel monitoring on A320 Family aircraft Flight operations Maintenance GENERAL TOPIC Engineering P36 High-altitude manual flying Ground operations

8 006 Safety First #20 | July 2015 PROCEDURES Control your speed... during climb Control your speed during climb Second of a series of articles on the theme of speed control during a flight, which started in issue #18 of this magazine, we have just taken off and are now entering the climb phase. The main objective is to retract the slats / flaps at an adequate speed, while sustaining enough lift to accelerate and climb. LORRAINE PHILIPPE DE BAUDUS CASTAIGNS Flight Operations Experimental Test Pilot Standards and Safety management

9 Safety First #20 | July 2015 007 After take-off, the aircraft continues in the climb phase and flies away from the busy airspace. The objective for the crew is to accelerate to the en-route climb speed and at the same time, manage various aircraft configuration changes, usually consisting of gears, slats and flaps retraction, and a change from take-off power to climb power. This article aims at shedding some light on the way the different maneuvering and limit speeds that are of use during climb are defined and determined, and how they can be implemented in daily operations. MANAGING YOUR CLIMB: UNDERSTANDING SPEEDS A climb is generally flown at an airspeed that is often initially limited by Air Traffic Control (ATC) instructions. To safely manage the climb phase within these restrictions, some characteristic speeds are useful tools, and they require a close monitoring. What speeds exactly should be monitored? What do these speeds mean and what happens if they are exceeded? For every flight, characteristic speeds Our objective is to highlight the design F, S and are computed automatically by the and operational considerations under- Green Dot speeds aircraft Auto Flight Systems (Flight Management System (FMS), Flight lying all recommendations Airbus has issued to flight crews regarding the frame the aircraft Guidance (FG) and Flight Enve- monitoring of these speeds during climb performance lope (FE)) and effectively displayed climb. limits. on the PFD airspeed scale. They Amongst other parameters, the maneu- are extremely useful as maneu- vering speeds Flaps (F), Slats (S) and vering speeds and limit speeds to Green Dot (GD) are a function of the safely guide the pilots configuration Zero Fuel Weight (ZFW) inserted by the change decisions through the climb crew at FMS initialization. Therefore, any phase. erroneous entry will impair these speeds. Maneuvering speeds In nominal conditions (all engines oper- help pilots fly their aircraft safely through ative), the climb phase poses some the different steps of this phase of challenges to the crew: accelerate the flight, some characteristic speeds were aircraft, maintain a satisfactory climb defined as maneuvering speeds. gradient and manage several config- F, S and Green Dot speeds frame the uration changes at the same time. To aircraft climb performance limits.

10 PROCEDURES Control your speed... during climb F and S: Flaps and Slats minimum retraction speeds Definitions F speed is the minimum speed at S speed is the minimum slats retrac- which flaps should be retracted from tion speed, i.e. the minimum speed at CONF 3 or 2 to CONF 1+F. which a clean configuration should be selected. F speed It is represented by a green F on the PFD speed scale and displayed only It is represented by a green S on the when the slats / flaps control lever is PFD speed scale and displayed only on position 3 or 2 (CONF 3 or 2) dur- when the slats / flaps control lever ing the take-off phase, the initial climb is on position 1 (CONF 1 and 1+F) and go-around (fig.1). It is no longer (fig.2). (fig.1) displayed when in configuration 1 or F on the PFD speed scale 1+F. How are F and S determined during the take-off phase? F speed varies according to the air- In this respect, F speed allows a mar- craft weight and altitude. It is tab- gin above the stall speed in the con- ulated in the Flight Envelope as a figuration 1+F. function of VS1g CONF 1+ F , which is the reference stall speed demonstrated by flight tests and agreed by the Air- S speed worthiness Authorities. F speed = k x VS1g CONF 1+F , with k equal to about 1.18 to 1.26 VMCL + 5 kts F VFE CONF FULL 2 kts S speed varies according to the air- In this respect, S speed allows a mar- (fig.2) craft weight and altitude. It is tabu- gin above the stall speed in the clean S on the PFD speed scale lated in the Flight Envelope as a func- configuration. tion of VS1g CLEAN CONF. S = k x VS1g CLEAN CONF , with k equal to about 1.21 to 1.25 Green Dot (GD): best lift-to-drag ratio GD speed Definition GD speed is the engine-out operat- represents the operational speed of ing speed in clean configuration. In the clean configuration and the rec- other words, it corresponds to the ommended speed in holding in clean speed that allows the highest climb configuration. gradient with one engine inoperative in clean configuration. It is represented by a green dot on the In all cases (all engines operative), PFD speed scale and displayed only (fig.3) the GD speed gives an estimate of when the slats / flaps control lever is in GD on the PFD speed scale the speed for best lift-to-drag ratio. It the 0 (CLEAN) position and landing is also the final take-off speed and it gears are not compressed (fig.3).

11 Safety First #20 | July 2015 009 How is GD determined? GD speed is computed by the Auto- ture and aircraft weight, in clean con- flight systems and is based on the figuration with one engine out. aircraft weight. The GD formula has In some phases of flight, GD is com- been set up so that the resulting air- puted to minimize drag and thus, the speed provides the best lift-to-drag fuel consumption (for example during ratio for a given altitude, air tempera- the HOLD phase). Limit speed We have seen that deviations from the maneuvering speeds F, S and GD during climb can have an impact on the aircrafts aerodynamic performance. We will now focus on the limit speed VFE. VFE: Maximum speed with Flaps Extended With the A/THR engaged and active When the A/THR is not active, VFE (CLB / OP CLB / SPEED green on exceedance may occur (for example FMA), the aircraft remains below VFE. during a go-around). Definition VFE is the maximum speed with flaps gears extended) or VFE according to extended. It has a specific value for the aircraft configuration. VMAX is equal each flap setting. to VMO (or speed corresponding to Generally speaking, the maximum MMO) only in the clean configuration. speed defining the aircrafts flight On the PFD speed scale, it corre- envelope is called VMAX. VMAX is equal sponds to the lower end of the red and to VLE (maximum speed with landing black strip (fig.4). V display How is VFE determined? VFE is the maximum speed for high lift trol surfaces position), depending on configurations, i.e. with slats / flaps the aircraft type. extended: it is related to the structural limitation of the slats / flaps. A VFE is In order to keep a sufficient margin computed for each slats / flaps con- between the VFE CONF 3 and the speed figuration, based on either the slats / at which the next configuration is flaps control lever position or the actual selected, the following inequality is (fig.4) aircraft configuration (slats / flaps con- met: VFE CONF 3 F + 10 kts. V on the PFD speed scale

12 PROCEDURES Control your speed... during climb MANAGING YOUR CLIMB: OPERATIONAL RECOMMENDATIONS Flying a safe and steady climb requires pilots attention to carefully manage the different configuration changes, while accelerating to the en-route climb speed and eventually, cruise speed. Indeed, not respecting the maneuver- quences - is important. It is therefore ing and limit speeds leads to adverse worth understanding the different VFE consequences that we will review. display logics implemented in each Avoiding an overspeed situation dur- aircraft family, and the resulting over- ing the slats / flaps retraction - with speed aural warning behaviour during its potential structural damage conse- the climb. What are the operational implications of not respecting the maneuvering or limit speeds? F and S: Flaps and Slats minimum retraction speeds F speed (resp. S) is defined as the rec- Retracting the flaps (resp. slats) at ommended minimum flaps (resp. slats) a speed significantly higher than F retraction speed. Retracting the flaps speed (resp. S) would reduce the (resp. slats) at a speed significantly lower climb performance and thus, possi- than F (resp. S) would reduce the margin bly compromise the aircraft ability to against the high Angle-Of-Attack (AOA) clear any obstacles (this is more likely protection. This could lead the aircraft to if one engine is inoperative). reach a speed below the lowest selecta- If flaps need to be maintained for a turn ble speed VLS CONF 1 (or 0), and pos- before acceleration altitude for instance, sibly low enough to break through the F speed (resp. S) can be used safely to high AOA protection threshold. perform a turn while climbing. GD: Green Dot At a given weight and engine rating, been set to CLIMB / MCT), then the the potential climb gradient is maxi- only way for the crew to recover a sat- mum when (Thrust Drag) is at a isfactory climb gradient is to decrease maximum - i.e. when the lift-to-drag the rate of climb (even enter a descent ratio is maximum. if necessary) in order to accelerate to or above GD. This maneuver is obvi- Deviating below GD involves an ously counteractive to the objectives increase in the drag on the aircraft of the climb phase. and would eventually undermine the GD IN A NUTSHELL aircrafts ability to continue a climb. Therefore in the clean configuration, Indeed, if the aircraft speed goes sig- the crew should not fly below GD in Avoid flying below nificantly below GD, with the maxi- order to avoid degrading climb per- GD during climb. mum available thrust already in use formance. (assuming that thrust levers have just

13 Safety First #20 | July 2015 011 VFE: Maximum speed with flaps extended In case of take-off with A/THR The flight crew will have to reduce not active, flying with slats / flaps the speed or to retract the slats / extended, or extending slats / flaps flaps accordingly. well above VFE directly poses a risk of Exceeding VFE may subsequently structural damage through the slats trigger inspections of the slats/ / flaps track mechanisms. This may flaps mechanism and/or the aircraft result in distortion of the flaps and structure. slats or the extension mechanism or Specific trouble shooting procedures even the aircraft structure upstream. exist to inspect and repair an aircraft In case VFE is exceeded, an over- after flight above VFE. These proce- speed aural warning is triggered in dures are available in the Aircraft the cockpit in order to alert the crew. Maintenance Manual (AMM). VFE IN A NUTSHELL Do not fly with slats / flaps extended above VFE. How to avoid an overspeed during slats / flaps retraction? Avoiding an overspeed during slats changes, understanding of the limit / flaps retraction relies on a variety speed and of the different VFE display of complementary aspects. Proce- logics and overspeed aural warning dures, pilots attention and coordi- behaviour implemented in each air- nation, anticipation of configuration craft family. The common approach Slats and flaps retraction during task by anticipating them. During the climb can be managed safely by fol- initial climb phase, the PM needs to lowing SOP, and observing the visual be vigilant to speed trends and alert F and S indications on the PFD. Inci- the PF in case the margin that is left dentally, doing so allows the crew to against the applicable limit speed VFE respect the VFE indication displayed becomes too tight. on the PFD and thus, avoid trigger- This is valid at all time, for all aircraft ing an aural overspeed warning (with families. potential structural damage). The use of A/THR also enables the Differences arise when we look more crew to avoid an overspeed condi- closely at the VFE display logics for tion during slats / flaps retraction. each family. In particular, we want to emphasize the possibility of a tem- While the PF is expected to manage porary, yet inconsequential, over- these configuration changes, the PM speed aural warning on A300/A310, plays a key role in facilitating his/her A320 and A330/A340 Families.

14 PROCEDURES Control your speed... during climb The case of untimely temporary overspeed aural warning during slats / flaps retraction A300/A310, A320 and A330/A340 Families On A300/A310, A320 and A330/ This is due to the following logic: A340 Families, When the flap lever is moved from The VFE value displayed on the PFD CONF 2 (or 3) to CONF 1+F, F speed is based on the slats / flaps con- could be very close to VFE before flaps trol lever position and it moves by retraction. Once the flap retraction is one step as soon as this lever is initiated, VFE CONF (2 or 3) moves in one moved. step to VFE CONF 1+F before the flaps The overspeed aural warning trig- actually reach CONF 1+F. As a con- gering threshold varies according sequence, in acceleration towards S to the actual aircraft configuration, speed, the VFE aural warning could i.e. the slats / flaps surfaces real activate although the actual surfaces time position. speed is below the displayed VFE. Therefore, during slats / flaps tran- When the flap lever is moved sition, the dynamic acceleration of from CONF 2 (or 3) to CONF 1+F, the airplane may lead to a temporary S speed could be greater than OVERSPEED WARNING even if the VFE CONF 1+F before the surfaces current speed is out of the red and retract. When automatic flap black strip displayed on the PFD. In retraction occurs, the barbers pole this situation, there are neither opera- does not move before the flaps tional consequences nor safety issues. fully retract. A350 and A380 Families On A350 and A380 Families, a differ- ing threshold. This means that the ent logic was developed. The VFE dis- two signals are perfectly synchro- play on the PFD is directly based on nized, thus the risk of an untimely the actual aircraft configuration, as is temporary overspeed warning is the overspeed aural warning trigger- eliminated. The case of temporary overspeed aural warning during slats / flaps retraction after a heavy-weight take-off In the particular case of a heavy- For example, an A320 at a Take-Off weight take-off, the risk of a tem- Weight (TOW) of 76T, S speed of 205 porary overspeed aural warn- kts, the pilot will order flaps retraction ing is increased. Indeed, in this most probably at or slightly above configuration, S speed is quite close to 210 kts, which is precisely the Flaps VFE CONF 1+F because the aircraft weight Auto-retraction speed. Once the slats is higher and the lift needed to climb / flaps control lever is in the retracted is higher too. Therefore the slats need position, the VFE red and black strip BEST to remain extended for longer. As a is no longer displayed on the PFD PRACTICE result, the crew will order flaps retrac- tion at a speed that might be higher speed scale. If the airplane acceler- ates rapidly, then the airspeed may After a heavy-weight take-off, do not than the Flaps Auto-retraction speed. catch up the actual instantaneous VFE delay slats / flaps 0 selection above In that case, should the acceleration momentarily, which will trigger the VFE S speed in order to prevent possi- of the airplane be rapid, a VFE aural aural warning. ble temporary VFE overspeed aural warning may momentarily trigger. Again, this logic is as per design warning. This logic is as per design and struc- and structural limits are not en- tural limits are not encountered. countered.

15 Safety First #20 | July 2015 013 During climb, in manual flight, the main risk is to experience an aural overspeed warning (with potential structural damage) as a result of a late slats / flaps retraction. Understanding the implications of climb speeds is paramount to enable pilots to sense instantly the available margin they have left to avoid exceeding the limit slats / flaps retrac- tion speed. In practice, once the aircraft is airborne, pilots must be fully cognisant of the airspeed as well as the speed trends at all time in flight. DID YOU KNOW To know more about speeds, read our brochure Getting to grips with aircraft performance, available on AirbusWorld. A presentation was also made at the 11th Perf and Flight Ops Conference in Dubai in 2011.

16 014 Safety First #20 | July 2015 PROCEDURES Lateral runway excursions upon landing Lateral runway excursions upon landing Lateral runway excursions upon landing have long been rather low on the safety issues list. With the remarkable improvements in other areas, they are getting higher up and deserve careful attention. The analysis of real cases allows for drawing interesting lessons on these events and reinforcing prevention. MATTHIEU MAYOLLE SAMUEL PELLET XAVIER LESCEU Stability & control Product Safety Test Pilot engineer enhancement analysis engineer

17 Safety First #20 | July 2015 015 Safety statistics show that runway excursions have become one of the most common types of accident worldwide. If significant effort was put on the prevention of longitudinal runway excursions, it turns out that lateral runway excursion events are becoming a growing concern. Addressing them efficiently requires a good understanding of how they originate and what contributes to their occurrence. This article will focus on the most safety critical veer off cases in terms of likelihood and severity consequences, namely: lateral runway excursions upon landing. It presents the outcome of a thorough analysis of a number of real cases and reviews the best operational practices to prevent lateral runway excursions upon landing. LATERAL RUNWAY EXCURSIONS UPON LANDING: A GROWING SAFETY CONCERN? What are we talking about? In the frame of this article, a lateral landing path, but many of these never runway excursion is: any aircraft get- divert sufficiently to leave the runway ting off runway markings, whether it surface and therefore never become gets off the runway concrete or not. classified as incidents or accidents. This implies that events at take-off and However, analysis of such minor during taxi (e.g. during U-turns on the events in the future may well be bene- runway) are not considered here. ficial as we seek more data and infor- mation on this complex issue. This definition is as valid as any other for describing facts. However, when it The events where aircraft get off run- comes to enhancing safety and more way markings need to be categorized specifically prevention, this definition according to what contributed to their is of little help. Indeed, the analysis of occurrence, thus what can be done lateral runway excursion events corre- to prevent them. sponding to this definition combines situations that are so different in terms Generally speaking, the most safety crit- of their underlying phenomena that it ical (as a result of likelihood and sever- is extremely challenging to derive effi- ity of consequences) veer off events cient mitigation measures. are the lateral runway excursions upon landing where the aircraft goes off run- Of course there will be many cases way markings at touch-down, or during where aircraft trajectories divert from the roll-out phase. This article will focus the runway centerline and the desired more particularly on them.

18 PROCEDURES Lateral runway excursions upon landing Statistics say a word For decades, accident statistics have example, 15% of RE accidents cause kept highlighting the three same acci- fatalities, and are the third source of dent types at the top of the list of fatal accidents. Yet, RE have become contributors, namely: Loss Of Control the main source of hull losses. In-flight (LOC-I), Controlled Flight Into A closer look at the evolution of the Terrain (CFIT) and Runway Excursion figures and tendencies over the past (RE). If virtually all CFIT and LOC-I acci- 20 years shows that CFIT and LOC-I (fig.1) dents lead to both fatalities and hull have significantly decreased whereas Evolution of the three main loss, other accident categories gene- Runway Excursion remains relatively accident categories from 1995 rate mainly only material damage. As an stable (fig.1). 0.30 0.25 0.20 0.15 0.10 0.05 0 1996 1998 2000 2002 2004 2006 2008 2010 2012 2014 Over the last decade, a huge effort was concern. Is it because of or thanks put on runway overrun to prevent them. to the progress made on the runway As a matter of fact, among the runway overrun front? Because they are more excursions, not only did they use to be reported than before? For other rea- the most frequent ones, but also their sons or any combination of reasons? consequences are statistically more Difficult to say, but through the events severe than that of lateral excursions. reported to Airbus by airlines, the trend The main issue addressed was then is clear: the number of lateral runway related to the management of aircrafts excursions is increasing. energy given the aircraft performance, deceleration, runway state Therefore it is worth to try and reinforce prevention, and to start with, under- In recent years, lateral runway excur- stand what lies behind real events. sions have emerged as a growing safety

19 Safety First #20 | July 2015 017 WHEN REALITY HELPS SHAPE THE SCOPE TO CONSIDER: AFTER TOUCH-DOWN, YES, BUT NOT ONLY Thanks to airlines support, 31 in-ser- bigger and the results more robust. vice lateral runway excursion events were reported to Airbus over a 2012- They were studied with a main question July 2014 period. A first analysis with in mind: is there a global or common a prevention objective in mind led to signature for these events that could distinguish between several lateral allow us to learn some generic preven- runway excursions categories due to tion lessons? Interesting insights could there being a variety of issues identi- be drawn from this work as we shall fied and therefore, a variety of potential see later. corrective actions. When searching for common contrib- Within the defined scope of lateral uting factors, two main families came runway excursion upon landing, 25 out: events from the initial 31 were consid- - weather environmental conditions ered as relevant and usable. - flying technique Of course, the events studied were These two aspects were found in a only those reported to Airbus and number of events, most of the time in therefore, they represented a limited combination with one another, but with sample. However, they were corrobo- variations as to their detailed nature. A rated by a study of the lateral runway closer look at these two fields allowed excursion events reported to Airbus for refining the understanding of the from 2007, making the sample much underlying phenomena.

20 PROCEDURES Lateral runway excursions upon landing Weather environmental conditions Three main environmental factors came 22 events out of 25 analyzed involved a out of the analysis: wet or contaminated runway. In 19 out (fig.2) - Runway state, wet or contaminated of the 25, there were at least two of the Categorization of RE events - Turbulences or cross-wind aforementioned environmental factors according to contributing weather conditions factors - Visibility deterioration in the situation (fig.2). Dry runway (3) Wet or Contaminated runway (22) Visibility deterioration (12) A330-A340- A350 Family / A380 A320 Family Lack of control of the lateral trajectory before Touch Down Contaminated (SNOW or FLOODED) Turbulences or Crosswind (12)

21 Safety First #20 | July 2015 019 Awareness Problem before Touch Down (1) Lack of control of the lateral trajectory before Touch Down (12) A330-A340- A350 Family / A380 A320 Family Visibility deterioration Long flare (t 8s) No or insufficient Poor control High approach decrab before on ground (13) speed (1) Touch Down (7) Flying technique (fig.3) Categorization of RE events according to contributing Regarding the flying technique in the A major outcome of the analysis is flying technique factors environmental conditions mentioned the significant contribution of the air- earlier, three areas were identified phase, before touch-down, to lateral as contributing factors to the events runway excursions. occurrence: - Control of the lateral trajectory before The next question, and more precisely, touch-down THE question is: With these insights - Flare and decrab before touch-down from real events, how to enhance pre- - Ground control vention of lateral runway excursions? If there is nothing we can do to change In some situations, as illustrated in environmental conditions, it seems (fig.3), there was a combination of worth going back to some operational them. best practices.

22 PROCEDURES Lateral runway excursions upon landing PREVENTING LATERAL RUNWAY EXCURSIONS UPON LANDING: BEST OPERATIONAL PRACTICES As stated earlier, handling issues turn What is the appropriate landing tech- out to be a significant contributor to nique and why? Lets prepare for land- lateral runway excursion events upon ing and review the technique, including landing, especially under some difficult some explanations behind the scene, environmental conditions such as wet with a special focus on the conditions or contaminated runway or cross wind that were highlighted by the lateral run- or turbulence. way excursion events analysis. Landing technique: general principles The appropriate landing technique, what- information and awareness (e.g. environ- ever the weather conditions, is a whole mental conditions), state of mind & pre- that combines a variety of dimensions: paredness and handling skills. 1/ Before flare Be stabilized Be aware of the landing conditions Be stabilized until the flare. If not, go-around. If landing with crosswind or on a con- In a number of events, there was taminated runway rely on specific a localizer deviation away from the techniques, the first thing to make sure centerline. Beyond the lateral control of is that: before touch-down, it is essential that - the crosswind, if any, is and remains the aircraft be on the correct lateral within the limits of the aircraft and vertical flight path at the correct - the runway state allows for a safe configuration and speed up to the initi- landing and the runway braking coef- ation of the flare. ficient is known. Be Go-Around minded, as long as Be correctly seated needed As long as reversers are not During cruise, sometimes a long one, Experience shows that some pilots pilots may move their seat a bit. Yet, are increasingly reluctant to initiate a selected, a go- upon landing, the full deflection of go-around as the aircraft gets closer around is always all flight control and braking may be to the ground, even if the aircraft is not needed to control the situation. There- well aligned with the runway. Neverthe- possible. fore, make sure the pilot seat is in a less, from a safety viewpoint, initiating a position (both horizontally and vertically) go-around close to the ground or even to allow for those full deflections should after a bounced landing is always better they be necessary. This is a key prelim- than performing an unsafe landing. inary condition to a safe landing. 2/ From flare to touch-down Use proper flare and decrab (if needed) flying techniques Landing in the correct zone, with the In the case of crosswind, this requires right alignment and at the right energy specific techniques that will be detailed level is a good summary of what a pilot in the next section in this article. should aim at. Easier said than done?

23 Safety First #20 | July 2015 021 3/ After touch-down Fly until you vacate the runway Do not relax immediately after touch- makes the day more difficult. Indeed, a down. There is still work to do. number of physical phenomena come into play requiring specific actions A number of lateral runway excursions to be managed. More details about resulted from poor ground control in these phenomena and how to main- the rollout phase. This is obviously tain ground control with crosswind is more often the case when a crosswind provided in next section in this article. Landing with crosswind As general principles, the landing - Be go-around minded as long as technique mentioned earlier remains needed valid. However, it is worth getting a bit - Use proper flare and decrab flying further into details and background techniques explanations when crosswind is in- - Fly until you vacate the runway volved in the landing conditions such as those underlined hereafter: Lets examine how these three princi- - Be aware of the landing conditions ples translate into practice in case of - Be correctly seated crosswind and why. - Be stabilized Be stabilized In crosswind situations, the major approach to correct for the crosswind difference in technique lies in how to component on the final trajectory to keep the aircraft on the correct lateral the runway. Adopting a crab angle flight path. In order to do so, it is nece- allows the pilot to keep the aircraft tra- ssary to fly a wings level and crabbed jectory along the runway axis (fig.4). A CRABBED APPROACH (fig.4) Aircraft attitude during a crabbed approach Crab angle Runway axis

24 PROCEDURES Lateral runway excursions upon landing But what does correct lateral flight izer antenna, under the radome, at the path mean precisely? What part of center of the nose of the aircraft below the aircraft needs to be aligned with the cockpit (fig.5), correct lateral the runway axis? The answer is the flight path means localizer centered same whether the approach is flown or nose of the aircraft trajectory aligned (fig.5) manually or not, in visual conditions with the runway axis, thus ensuring the Location of the localizer or not. The reference is the cockpit. pilots eye is aligned with the runway antenna Considering the location of the local- axis. The localizer antenna is located under the radome in the center of the aircraft Some common tendencies to be avoided. Experience shows that in some situa- - When initially becoming visual tions, some pilots have tendencies to below a low cloud ceiling destabilize the aircraft approach trajec- - When performing the decrab in the tory, especially along the lateral axis. It flare. happens mainly in these 3 cases: Lets revisit the first two cases, see what - When disconnecting the Auto Pilot happens behind the scene and then (AP) for a manual landing. deal with the third case in more depth. When disconnecting the AP A tendency sometimes observed is to what it was under AP. Therefore, it that of making large inputs on the side- is key to analyze the stable trajectory stick when disconnecting the AP. Yet, before any stick input. This should the aircraft attitude has no reason to avoid large inputs on the sidestick. change at this very moment compared When becoming visual When first seeing the runway, some ral flight path. Again, becoming visual pilots have a tendency to start an makes no difference as to the correct immediate decrab and align the air- aircraft trajectory. It is normal to keep a craft with the runway axis. By doing so, crabbed approach and see the runway the aircraft drifts due to the crosswind from a certain angle. and moves away from the correct late-

25 Safety First #20 | July 2015 023 Use proper flare and decrab flying techniques Flare If the flare technique is not modified - In case of an extended flare, the by the presence of crosswind, some decrease in the aircraft energy will aspects need to be particularly kept in make it even more sensitive to cross- mind in such situations, especially: wind. Counteracting crosswind - A high or extended flare significantly becomes more and more difficult as increases the landing distance, speed decays in the flare. Eventually, whereas, due to possible adverse the crosswind may move the aircraft reversers effects explained later in away from the centerline. this article, it is even more important than usual to keep as much runway In summary, flare at normal height and length as possible to decelerate after do not look for a kiss landing. touch-down. Decrab As mentioned earlier, keeping a crabbed detail to better understand what results approach is the only way to keep the from this action on the rudder. Indeed, aircraft on the correct lateral flight path. when doing so, the aircraft will move a However, before touch-down, the air- bit towards the wind. Why is it so? craft needs to be decrabbed to align In fact, when pushing on the rudder, the with the runway axis. The aircraft is to be aircraft will yaw around a vertical axis decrabbed at the time of the flare, using that is located a bit forward from the CG, the rudder. the yaw axis. The moment induced will (fig.6) make the aircraft move slightly towards Forces and moments effects However, it is worth going into further the wind as illustrated in (fig.6). on aircraft during decrab Ground speed Air speed Ground speed Air speed Sideslip WIND WIND WIND Airborne, before the decrab Rudder input effects : Moment and force effects: - Side force on the fin - Rotation around a point - Yawing moment located slightly in front of the Center of gravity - Sideslip appears

26 PROCEDURES Lateral runway excursions upon landing FLARE AND DECRAB IN THE SPECIAL CASE OF HIGH CROSSWIND, ESPECIALLY ON CONTAMINATED RUNWAYS In such situations, allowing a slight Why 5 maximum for the crab angle? does not change immediately the CG bank angle to maintain the runway Here again, it is an appropriate speed vector. Therefore, if the aircraft axis, less than 5, and a small trade-off between maintaining the lateral flight path starts drifting away crab angle, less than 5, from the aircraft trajectory and experiencing from the runway centerline, using approach through to touchdown an acceptable load at the landing the rudder alone may not allow for is the only way to keep the cockpit gear on touch-down. an easy realignment of the aircraft. aligned with the runway axis. A common tendency to be avoided Should such drift occur too close Why 5 maximum for the bank to the ground, the safe practice is angle? It is the appropriate balance Some pilots appear to be reluctant to go-around. And as mentioned between the bank angle needed to to keep a bank angle, even a small earlier, as long as reversers are not keep the aircraft trajectory aligned one, prior to touch-down. They then selected, a go-around is always with the runway centerline and the try and compensate the crosswind possible! risk of hitting the runway with the impact using the rudder only. wing tip or engine nacelle. However, an action on the rudder

27 Safety First #20 | July 2015 025 Sideslip Sideslip Sideslip WIND WIND WIND On ground, to stay on the Without rudder pedal input, runway centerline, a rudder a large yawing moment pedal input is necessary. will make the aircraft turn to It cancels the weathercock the wind effect mainly due to the fin WIND WIND WIND Fly until you vacate the runway (fig.7) Counteracting the weathercock effect After decrab When the main landing gear touches towards the wind direction by weath- the ground with residual crab, a pivot- ercock effect. Indeed, the effect of the ing moment is created around a verti- wind on the aircraft fin aligned with the cal axis located at the level of the main runway axis induces a rotation of the landing gear by the combined effect aircraft around a vertical axis located of the lateral friction of the tires on the at the CG that yaws the aircraft nose surface and by the inertia force applied back towards the wind. This opposite at the center of gravity. This moment moment thus tends to move the air- tends to turn the aircraft so as to align craft upwind, away from the center- the aircraft longitudinal axis with the line. It needs to be counteracted by ground speed vector. In short, wheels the rudder. tend to be more willing to go in the same direction as the aircraft trajec- Nevertheless, as the aircraft speed tory, more than to skid. The intensity of decreases, the rudder efficiency the pivoting moment depends a lot on drops. Therefore, the action on the runway friction. rudder to counteract the weathercock effect needs to be amplified (fig.7). However, the sideslip coming from As speed further decreases, the rud- the crosswind when the aircraft is der effect could become insufficient, decrabbed creates an opposite therefore the pilot must be prepared to moment tending to yaw the aircraft apply differential braking.

28 PROCEDURES Lateral runway excursions upon landing (fig.8) Roll-out Forces exerted on the aircraft when reversers are used During the roll-out, the primary means braking on the pedals when they are to maintain the aircraft on the runway not aligned, the use of Auto Brake is is the cornering force exerted on the highly recommended. wheels through the tires. However, in order to keep the aircraft on the run- Destabilizing reversers effect way, it is important to understand some On slippery runways, the aircraft may wind and aircraft related aspects. start leaving the runway axis and going X- WIND downwards the wind when reversers Auto Pilot disconnection effect are used. Indeed, in slippery condition, As long as the Auto Pilot (AP) is con- the moment created by the tires fric- nected, the aircraft automatically com- tion that tend to align the aircraft fuse- pensates the effects of crosswind with lage on the runway axis, is not effec- the rudder. As for the pedals, they tive enough. And if the aircraft remains X force remain in the neutral position. Yet, at crabbed, the reverser thrust resultant AP disconnection after touch-down, force can be resolved in 2 compo- since the pedals are at neutral posi- nents (fig.8): tion, the aircraft fin will naturally go - One parallel to the runway and actu- back to a centered position, expos- ally stopping the aircraft. ing the aircraft to weathercock effect, - One perpendicular to the runway, in Stopping Resultant thus aircraft nose movement towards the same direction as the wind, i.e. force force the wind, away from the centerline, adding to that induced by crosswind. unless immediately countered by the pilot. Countering the weathercock This second force may make it more effect requires immediate inputs on difficult to control the aircraft on the rudder pedals, possibly large inputs. It ground. Therefore, if a directional may even be that differential braking is problem occurs: needed in addition to inputs on rudder - Consider reducing reverse thrust. pedals in case of high crosswind. - If braking manually, consider reduc- ing braking temporarily or use differ- Therefore, at AP disconnection after ential braking. touch-down it is key to: - Have your FEET UP on the pedals Once directional control is recov- - Be ready for immediate and possibly ered and the aircraft is on the runway large inputs on rudder pedals centerline again (fig.9): - Be ready to use differential braking in - Manual braking can be re-applied addition if needed and keep in mind - Reverse thrust can be re-applied (only (fig.9) that the rudder effectiveness reduces the component parallel to the runway Recovering from the destabilization when speed decreases. Considering remains with no adverse effect on the effect of thrust reversers the difficulty in performing a balanced lateral control of the aircraft). X- WIND

29 Safety First #20 | July 2015 027

30 OPERATIONS Fuel monitoring on A320 Family aircraft Fuel monitoring on A320 Family aircraft Since the first A320 entry into service, very few events have involved undetected fuel quantity issues. Yet, coming across a situation where engines shut down by lack of fuel is a situation no one wants to experience. GRALDINE VALLE REGIS PERNET ALBERT URDIROZ Product Safety Flight Operations Director Flight Safety Enhancement manager engineer

31 Safety First #20 | July 2015 029 If fuel systems have proven their reliability, in case of failure, the ultimate safety barrier to avoid finding oneself in a fuel critical situation is fuel monitoring by the crew. Lets go back to some fundamental questions around fuel monitoring on A320 Family aircraft. How to determine the fuel quantity available in the tanks? What are the various sources of information and how redundant are they? Why is it key to perform regular fuel checks? RARE BUT STRIKING EVENTS In more than 25 years of Airbus A320 The reasons for these fuel quan- Family aircraft operation, there have tity issues vary from one event to been not more than a handful of another. Early detection and mana- events involving undetected fuel quan- gement of the issue remains key to tity issues. successfully deal with such events. Event 1 During cruise of an A320 Family air- and passengers disembarked safely. craft, the crew observed 3 occur- The remaining fuel quantity upon land- rences of the ECAM warning L TK ing turned out to be 840 kg in the right PUMP 1 + 2 LO PR. In line with this fuel tank, and no fuel in the left tank. warning, they noticed a more rapid Investigation into this event highlighted fuel level decrease in the left fuel tank that maintenance was done on the compared to the right one. Following fuel tanks prior to the event flight, and the applicable FCOM procedure, they both engines 1 and 2 fuel pump filters opened the fuel cross feed valve, only had been replaced. After the event to close it soon after as fuel quantity flight, engine 1 HP fuel pump filter was abnormally decreasing. Minutes cover was found not properly fitted, later, engine 1 shut down by itself and with 4 threaded inserts out of 6 being the ECAM warning ENG 1 FAIL trig- reported unserviceable, thus allowing gered. the cover to partially open. It was esti- The crew managed to land the aircraft mated that approximately 4 to 5 tons uneventfully with engine 2 still running, of fuel had leaked. Event 2 In another event, the Fuel Quantity For the event flight, the aircraft departed Indication (FQI) system had been with an indicated FOB of approximately showing discrepancies for a period 5000kg (fuel at arrival from previous leg of time. Given the intermittent nature was approx. 3800kg and fuel uplift was of the fault, entries in the aircraft 1200kg). The flight crew performed the logbook were investigated but with- initial fuel checks with reference to the out findings by maintenance despite fuel logs of the preceding flight. The cal- carrying out precautionary mainte- culated values remained consistent. nance. On two occasions, different crews failed to identify or properly In flight, transient fuel quantity fluctu- record the FOB discrepancy du- ations were experienced and eventu- ring pre-departure or post-flight fuel ally the ECAM alert FUEL L (R) WING checks. TK LO LVL triggered. It was pro-

32 OPERATIONS Fuel monitoring on A320 Family aircraft cessed as per SOP by the crew who confirmed empty with the FQI over checked the SD page as being no- reading by 1 ton. minal. The alert was thus considered spurious. The flight continued with The analysis of the event indicated repeated fuel checks at short inter- that preceding fuel log entries did not vals; however during the approach, allow the crew to identify a significant engine 1 flamed out. Landing was discrepancy of about 800 kg prior to performed on engine 2 safely. departure. After the flight, the left wing tank was Event 3 On the third flight of the day on an During the second flight of the day, the A320 Family aircraft, while the aircraft discrepancy calculated by the crew at was approaching its destination, a LO arrival was almost 3000 kg. The First LVL alert triggered on one side. The Officer noticed that it was not what he crew considered it spurious, as likely had expected but considered that they resulting from fuel movement in the had benefited from a number of favora- tank. Shortly after this first alert, a new ble factors such as a direct ATC rou- LO LVL alert triggered on the other ting, and they eventually had arrived side. The crew continued the flight and 20 to 25 minutes earlier than sched- eventually landed uneventfully. The uled. In addition, they sometimes ferry remaining fuel quantity upon landing fuel according to the company policy. turned out to be approximately 900 As a consequence, nothing unusual kg. was mentioned in the log book. During the first flight of the day, the Before the third flight - which was flight crew calculated a ~500 kg dis- the event flight - the refueler only crepancy at arrival. Nothing was men- added little fuel since there was still tioned in relation to fuel in the log book. a fuel over read. Yet, the flight crew

33 Safety First #20 | July 2015 031 departed with a significantly over- read was due to an intermittent FQI estimated fuel quantity that ulti- Computer (FQIC) failure. The mainte- mately led to the unanticipated LO nance record of this FQIC highlighted LVL alerts on both sides. According numerous returns to the shop in the to the investigation, the issue/over- months preceding the event. HOW MUCH FUEL IS AVAILABLE ONBOARD? Considering the consequences of information relate to one another? running out of fuel in flight, knowing Are they independent? Lets explore how much fuel is available on board the various types of onboard fuel during the flight is clearly essential to information that are available to the safety. What information can be used flight crew. Where does this infor- to determine the amount of fuel on mation originate and how are fuel board? How is this information esta- levels established on Airbus A320 blished? Do the various pieces of Family aircraft? FQI or Fuel Quantity Indication: a source based on measures performed inside fuel tanks The FQI system calculates the fuel Yet the information that is needed quantity based on values taken from by pilots is the quantity of fuel on probes in the tanks. The probes meas- board expressed as a weight. The ure the level of the fuel in the tank, as translation of fuel volume into fuel a consequence of changing capaci- weight is performed by the FQIC (fig.1) FUEL System page on Lower tance due to the amount the probe is using the fuel density measured by ECAM Display Unit immersed. This allows the determina- specific devices in each wing tank tion of the fuel volume in the tank. (fig.1). INFORMATION The low level sensing does not appear on the System Description page. Therefore, for fuel indication, do not rely on SD page only. Fuel Flow Meters: a source based on engines consumption Each engine is equipped with Fuel Flow mation is integrated by the FADEC and Meters that measure the quantity of fuel provides pilots with information on the consumed by the engine. This infor- fuel used. Low level sensors: an additional independent source based on dedicated sensors in the wing tank In addition to the sensors and three independent dedicated low probes feeding the FQI system, level sensors. These sensors are each wing tank is equipped with located in such a way that they

34 OPERATIONS Fuel monitoring on A320 Family aircraft become dry when the remaining - Do not provide pilots with a continu- fuel in the tank is approximately ous indication of the fuel quantity in 750 kg. If two sensors in the same the wing tanks, but only the signal that tank remain dry for more than 30 the fuel level has reached below 750 seconds, a low level alert triggers kg (threshold crossed). in the cockpit (fig.2). - The information provided to pilots in The low level sensors are fully inde- the form of the low level alert results pendent from the Fuel Quantity Indica- from a physical measure (sensors dry tion, and are different in that they: or wet) rather than from a calculation. DID YOU KNOW The A320 Family aircraft low level indication is based on remaining fuel quantity in the tank being sufficient to meet the requirement of 30 minutes at 1500 ft (corresponding to (fig.2) approximately 1 200 kg). Should the low level alert trigger on both fuel tanks, the total Low level alert display on ECAM remaining fuel is: 750kg + 750kg = 1 500 kg. INFORMATION The low level The presence of water in the fuel tanks can lead to erroneous (over reading) fuel indi- sensors are fully cations. The parameters used by the fuel system (density and capacitance) are highly affected by the presence of water. Flight deck effects of a buildup of water in the fuel tanks independent from include fuel gauging fluctuations and over reads. the Fuel Quantity Consequently, among the maintenance tasks that are to be performed if pilots detect an ab- Indication. normal fuel indication during a fuel check is fuel tank draining (fig.3). This can also help to pre- vent microbiological contamination, which is often another cause of fuel gauging fluctuations. (fig.3) Maintenance Planning Document ATA 28 Fuel Task FUEL CHECKS 281100-01-2 Drain water content in tanks An unnecessary burden or essential safety net? Ensuring an accurate awareness of ler and fuel consumption figures the quantity of fuel on board requires during flight, are all important. But use of several sources of data. Cer- to ensure the information remains tainly the FQI is the primary source accurate, the safety barrier com- of fuel indication, but the other key mon to all cases is fuel monitoring sources such as the Fuel Used, by the crew. the fuel uplifted at the latest refuel, the crosscheck between what is Although fuel checks with the manual expected to be uplifted and what is calculations they involve can some- uplifted, information from the refue- times be perceived as a tedious task,

35 Safety First #20 | July 2015 033 they form in reality an integral part of ate measures to secure the safety of the measures taken to ensure safe operations. They were designed and the flight. They are applicable to all Airbus Families aircraft from the first The fuel meant for detecting as early as pos- A300B to the latest A350, and remain available onboard sible any fuel quantity issue, ensur- an essential part of airmanship when can be determined ing timely and accurate maintenance piloting the A320 Family aircraft. intervention, and allowing appropri- based on two independent What is to be checked and when? sources of The maximum efficiency of fuel larly and at different times to either information checks relies on the flight crew per- confirm anticipations, or detect any even three in case forming a number of checks regu- discrepancy. of low level. Before start The first fuel check to be performed is available for the flight. This check con- before start to consolidate the infor- sists in making sure that: mation about the total amount of fuel Initial Fuel On Board (FOB) + Fuel Uplifted = Fuel On Board (FOB) Where FOB is the fuel quantity derived from based on the uplifted fuel density. the FQI system is an acceptable tolerance (see Fuel Uplifted is the amount of fuel indi- Why do we need to consider a cer- cated by the refueler as having been tain tolerance on fuel onboard val- added during refueling. This may ues? insert). require converting volume into weight, During the flight During the flight, fuel checks mainly the FMS fuel predictions too optimis- aim at detecting any abnormal con- tic and potentially lead to fuel exhaus- sumption, be it due to a leak or unan- tion in flight. ticipated drag (e.g. spoiler or landing To ensure that there is no undetected gear, slats or flaps not fully retracted) fuel leak, the following calculation or any other reason. should be performed at each way Indeed, such situation would make point or every 30 minutes: Fuel On Board (FOB) + Fuel Used = Initial Fuel On Board (FOB) Where Fuel Used is derived from the fuel flow meters In addition, the remaining FOB and Fuel Used values must also be consistent with the values given by the computed flight plan at each waypoint.

36 OPERATIONS Fuel monitoring on A320 Family aircraft Post flight All fuel At the end of the flight, when the air- craft has reached its parking stand, ious sources and thus detect any abnormal discrepancy that would checks are equally a final fuel check is to be performed call for maintenance actions. The important in to check the consistency between post flight fuel check consists of the information provided by the var- making sure that: the detection and safe management Fuel On Board (FOB) + Fuel Used of any fuel quantity = Initial Fuel On Board (FOB) issue. NOTE WHAT IF A FUEL CHECK IS MISSED? Depending on the underlying reason for a fuel quantity issue, missing a fuel check may make it very difficult to detect. In the second event described, the failure of the Fuel Quanti- ty Indication Computer did not lead to a systematic wrong indication but rather to quantity fluctuations. The fuel quantity indicated by the FQI system before the first flight of the day was correct. In such cases, skipping a fuel check may be a missed opportunity to detect a failure that may not be detectable later on, at the time of the following check. More gener- ally, whatever the origin of a fuel quantity issue, detecting it as early as possible allows for managing it and making sure appropriate decisions can be made in time to best manage the rest of the flight as safely and efficiently as possible. WHY DO WE NEED TO CONSIDER A CERTAIN TOLERANCE ON FUEL ON BOARD VALUES? Due to the nature of the fuel system, it is essential that the system tolerance be taken into consideration when performing fuel quantity calculations. The overall FQI system accuracy is designed to take into consideration several factors such as: attitude effects, wing deformation, systems tolerances, manufacturing tolerances, component toleranc- es, environmental effects, fuel characteristics. These individual tolerances lead to an overall tolerance on the global system resulting from the worst case (maximum tolerance) on each individual element. The maximum tolerance is defined for the aircraft to guarantee an acceptable level of integrity of the measure and the associated fuel quantity information. When a fuel check is performed, any fuel discrepancy calculated by the crew and exceeding this value may then be considered abnormal. For an A320 Family aircraft, the instrumental tolerance on the ground is calculated as follows: (1% of current FOB + 1% max possible FOB for this aircraft) As an illustration, for an A320 aircraft, if there are 5 tons left in the aircraft, the maximum nor- mal tolerance value is: (5000kg (current FOB) * 1% + 20000kg (max FOB)* 1% ) = 250kg Note: The FQI system is designed in such a way that the lower the fuel quantity in the tank, the more accurate the fuel indication. The FQI system is calibrated on ground during manufacturing and its accuracy (as per the formula above) will remain the same throughout the operational life of the aircraft.

37 Safety First #20 | July 2015 035 TO FURTHER ENHANCE SAFETY Following the investigation of real events kg or lbs and will vary depending on the involving fuel monitoring issues, Airbus fuel on board and fuel uplifted. They will identified and implemented enhance- lead to a generic maintenance task in ments in several areas: the TSM (Trouble Shooting Manual). Further refinement of the description Service Bulletin A320-28-1214 for of the Fuel Quantity Indicating and level A318/A319/A320 and Service Bulletin sensing systems in the FCOM doc- A320-28-1202 for A321 aircraft intro- umentation. During the interactions duce a new fuel leak detection function, with the airlines involved, it turned out which eases and improves the detec- that the independence of the two fuel tion of a fuel leak. This new function is measures coming from respectively the meant to prevent situations where a FQI system and the low level alert was loss of fuel would remain undetected not clear to all crews. by the crew. Definition of empirical criteria on A320 A new FCOM evolution will be availa- Family aircraft to consider a fuel discrep- ble soon, that will describe the trigger- ancy abnormal or unusual when ing conditions of the low level alert in the performing the before start fuel check. procedure, and to show that the alert is These thresholds will be expressed in independent of the displayed fuel. DID YOU KNOW A GOLDEN RULE IN THE TROUBLE SHOOTING MANUAL (TSM) Until recently, there was no generic entry into the TSM in case of abnormal fuel quantity. It is therefore worth reminding everyone of a key sentence in the introduction of the TSM that encourages airlines to manage cases where there may be a doubt as to the aircraft airworthiness: If you cannot find a fault symptom and/or a fault isolation procedure necessary to en- sure the continued airworthiness of the aircraft, or if you think that the information given is not complete, contact Airbus. An engine failing in flight, because of fuel starvation, is a situation all pilots would like to avoid. In order to do so, and to ensure the continuing accu- racy of the FQI, performing thorough fuel checks before start, throughout the flight and after arrival at the parking stand is essential. Should any discrepancy appear, effectively tackling the underlying issue, be it intermittent or permanent, is the only way to prevent further fuel quantity indication and possible resulting safety issues. This relies on good cooperation between flight crews, maintenance and the manufacturer. Should the LO LVL alert trigger , it is to be trusted! It is the independent voice from the tanks themselves warning you

38 036 Safety First #20 | July 2015 Had I not known this, under- stood that or paid attention to that, I wouldnt be here with you today was a sentence Jacques often repeated when he referred to some of the thousands of flights he performed either as a fighter pilot or as an experi- mental test pilot. Sadly, Jacques is no longer with us today. He was a genius pilot, a humble man, a great man. Aviation was his passion, safety his quest. He was always ready to share his knowledge, experience and wisdom to improve safety, as he did with the following article. HE WILL BE MISSED

39 Safety First #20 | July 2015 037 GENERAL TOPIC High-altitude manual flying High-altitude manual flying Flying an aircraft manually at high altitudes, and therefore necessarily at high Mach number, is a completely different discipline to what it may be like at low altitudes. As it turns out, opportunities to experience manual flying at high altitudes are rare in a pilots career. Yet, regulations do require it in certain circumstances, such as when the Auto Pilot is unavailable. JACQUES ROSAY Experimental Test Pilot Former Airbus Chief Test Pilot

40 Most of the time, commercial aircraft fly at high altitudes, above FL 290. In other words, they fly within the RVSM (Reduced Vertical Separation Minima) space that extends from FL 290 to 410 included, and which now covers a very large part of the worlds airspace. As it turns out, use of the Auto Pilot (AP) within this airspace is mandatory, meaning that the regulations actually prevent the pilots from acquiring practical manual flying experience of their aircraft within the part of the envelope where they most often fly. Pushing this paradox further, in certain cases, especially if the AP is unavailable, these same regulations require that the pilots manually fly the aircraft to rapidly leave this airspace in coordination with air traffic control. In other words, pilots are requested to do maneuvers for which practicing in flight is prohibited. However, the behaviour of an aircraft at high altitude is significantly different from that of an aircraft at low and medium altitudes. The aim of this article is to recall some qualitative aerodynamic, flight mechanics and handling qualities notions specific to the high Mach numbers and to high altitudes, to share practical experiences lived by Airbus test pilots in these domains and to make suggestions for training. Lastly, note that, apart from passages specifically dedicated to the normal and alternate electrical flight control laws, the whole of this article applies to all types of commercial aircraft whether equipped with electrical flight controls or not. AERODYNAMIC ESSENTIALS The effects of Mach number The air flow around the wings accel- air flow accelerates on the upper sur- erates on the upper surface creating a face. Therefore, the local Mach number negative pressure and it is this nega- around the wings is much higher than tive pressure which mainly keeps the the aircraft flight Mach number and in aircraft up (fig.1). certain locations reaches transonic values. In high-altitude stabilised flight, When the altitude increases and the air shock waves can be seen at certain (fig.1) density falls, more aerodynamic speed locations by looking at the upper sur- Air flow around an airfoil is required to create the lift required for face through the cabin windows. a given lift configuration. This reduc- tion in the density and this increase in This sonic phenomenon around the the aerodynamic speed is accompa- wings leads to a degradation of their nied by an increase in the Mach num- aerodynamic properties. This, in turn, ber required for flight. We have seen leads mainly to a reduction in the that by passing over the wings, the maximum lift angle of attack as the

41 Safety First #20 | July 2015 039 Mach number increases, which sig- wings, another well-known phenome- nificantly reduces the stall margin. non is added to the previous one. As Thus, at a high-altitude normal cruise the local Mach numbers along the Mach number value, when the angle span are not identical, the distribution of attack is increased to produce the of the lift does not vary uniformly with load factor required to make a turn or the angle of attack. This creates non- a pull-out, the angle-of-attack limit is linearities in the longitudinal balance more easily approached than when of the aircraft most classically leading the same maneuver is done at low to spontaneous pitch-up tendencies altitude and at a low Mach number. or to self-tightening of the turn when Also, on most aircraft with sweepback the angle of attack increases (fig.2). (fig.2) Early stalled areas at high mach -> pitch up Early stalled areas along the wings Centre of gravity Clearly the aircraft has flight charac- in manual flying, the aerodynamic If a Pilot has teristics quite different at high altitude speed is 260 kt. When flying at FL350 compared with its characteristics at at M 0.85, at standard temperature, to fly manually at low altitude. This means that if a Pilot the aerodynamic speed is 490 kt. high altitude, he/she has to fly manually at high altitude, If the temperature is ISA + 12, the he/she will not find the characteris- aerodynamic speed is then 500 kt. will not find the tics he/she is familiar with at low alti- That is practically twice as fast as the characteristics he/ tude. In addition, the aerodynamic highest speeds usually seen at low she is familiar with speed, i.e. the speed in relation to altitude. the air molecules, therefore in rela- This difference is not without conse- at low altitude. tion to the earth coordinate system quences on flying. For example, for (excluding the wind), is much higher a maneuver at identical load factor, at high altitude. Consequently, the the radius of curvature of an alti- purely kinematic characteristics of tude capture is multiplied by four the vehicle are radically different. and therefore, starting from a given To get an idea of this, when flying in slope, anticipation for this maneuver the initial approach zone at 3000 ft must be multiplied by four in order and 250 kt, which is often the case not to exceed the target altitude.

42 GENERAL TOPIC High-altitude manual flying Compressibility stall We have seen that when the Mach for flight at supersonic speeds. Pilots number increases, the maximum lift who have flown on the T33 or the angle-of-attack is reduced (fig.3). Alpha Jet may perhaps remember having reached subsonic Mach num- We can imagine that at a certain point bers beyond which the wings were in the increase of the Mach, the angle- incapable of providing a load fac- of-attack can theoretically be so lim- tor of 1 g. Level flight could not be ited that the maximum lift the wings maintained: compressibility stall was are capable of producing becomes reached. The Mach number had to insufficient to sustain the weight of the be reduced to regain the load factor aircraft. In certain aerodynamic manu- authority required for straight level als, this theoretical point is called the flight. On the Alpha Jet in particular, compressibility stall. with a little patience and a very small It depends on the evolution of the amount of fuel on-board, it is even curve lift versus Mach. This change possible to climb to an altitude where depends on many aerodynamic chara- it was neither possible to decelerate cteristics of the aircraft, such as the due to low Mach number stall nor to (fig.3) wing profile, the chord, the sweep, accelerate due to compressibility stall. General tendency in the evolution of the maximum angle-of-attack () the span, etc. Remember that this There was only one single practicable versus the Mach number phenomenon does not exist on an flight point: the aerodynamic ceiling aircraft where the wings are designed was reached. Stall Mach Aerodynamic ceiling and buffeting margin In practice, even if the compressibili- is defined such that when an accelero- ty stall and the aerodynamic ceiling meter located under the pilots seat can theoretically exist in aerodyna- measures peak-to-peak accelera- mics in certain cases, they cannot be tions higher than 0.1 g. Therefore, the reached by a certified commercial air- aircraft MMO value and the lift ceiling craft and this for several reasons. Let (which depends on the weight) are by us see why. definition such that there is always a buffeting margin of at least 0.3 g and 1) The certification regulations require therefore, a margin well above the that throughout the flight envelo- compressibility stall is ensured. pe, up to MMO, irrespective of the weight, the aircraft must have a buf- 2) The certification regulations also feting margin of 0.3 g. require that the flight tests check This means that a load factor of 1.3 that the aircraft can fly above MMO g must be attainable before buffet up to MD. onset is encountered. Buffet onset MD is the highest Mach number at

43 Safety First #20 | July 2015 041 which the aircraft must be able to fly without structural anomalies (this is the flutter margin) and without substantial degradation in the handling qualities allowing the aircraft to be always easily controlled. It is determined by cali- brated maneuvers (FAA dive, JAA dive) defined by the certification regulations. In practice, typically MD = MMO + 0.06. DETERMINING MD IN FLIGHT TESTS During the flight test, MD must pitch attitude and then, the structure done with moderate buffeting, but be reached fairly quickly by is excited by programmed impulses the aircraft can still be controlled an accentuated dive before into the flight controls. The purpose and maneuvered. Beyond MD, the encountering another limit: the of this is to check that there are structural integrity of the aircraft is absolute speed limit VD (typically no divergent structure oscillations no longer ensured! Based on the VD = VMO + 35 kt), which is (flutter). Then, test pilots do a positive experience accumulated at Airbus approached as the altitude drops. pull-out, engines idling, to return to and seeing how many aircraft still For this, Airbus test pilots start from the normal flight envelope. This pull- respond very well at MD load factor, the aircraft ceiling, in direct law, at a out requires an important increase very serious structural problems will Mach as close to MMO as possible. in the load factor and demonstrates be encountered before finding a Then they accelerate by a dive with that compressibility stall is still far possible compressibility stall which, an attitude of around -15 at the start from being reached. However, if it exists, can be found only at Mach of the maneuver with engines at full the buffeting margin of 0.3 g is no numbers well above MD, probably throttle. When MD is reached, this longer observed beyond MMO and above Mach 1. Mach is maintained by adjusting the approach of MD at n = 1 is in reality To conclude, the regulatory criteria nomena cannot be physically encoun- related to the buffeting margin at MMO tered due to the design of the aircraft. and to the flight characteristics up to Compressibility stall does not exist MD imply that the compressibility on current commercial aircraft. stall and aerodynamic ceiling phe- FLYING MANUALLY Definition It would be interesting to survey obviously allows an accurate trajec- pilots as to what they understand tory to be followed, with correct cap- by the terms flying manually. Per- tures, and good control of the speed. sonally, I have often heard during These functions are provided for this test, demonstration, acceptance purpose. or airline flights, colleagues, young However, within the scope of this arti- or older, airline pilots or test pilots, cle, which concerns manual flying, proudly say that they would do such flying in this manner can in no way or such a part of the flight - in gen- be considered as flying manually. eral a complete approach followed Indeed, the orders given to the flight by a landing - in manual control controls by the pilot consist in setting mode. I would then observe how the Flight Director (FD) bars to zero, they performed and saw that all they which corresponds to the orders did was actually disconnect the AP generated by the guidance function. and servilely follow the Flight Direc- These stick inputs are actions done tor, leaving the Auto Thrust engaged. mechanically by the pilot but are in And this until start of the flare. This no way elaborated by him/her. These

44 GENERAL TOPIC High-altitude manual flying flight control orders are the same as able to correctly perform, at any alti- those which the AP would give if it tude, all the maneuvers required to was engaged. Thus, the added value manually control the aircraft and land provided by the pilot is rather nega- it under satisfactory safety conditions. tive, as the cognitive resources that These safety conditions would not be he/she uses to follow the FD bars met if a pilot is not at ease when per- are no longer available for the most forming, under all flight control condi- elaborate flight monitoring and con- tions which may be encountered fol- trol functions. In other words, this lowing failures, manual flying without exercise provides strictly nothing the FD, without the ATHR and without towards the manual flying training for speed vector, from the cruise ceiling the cases where the pilot would truly of the aircraft to instrument landing have to fly the aircraft manually. under CAT1 weather conditions. The type certifications of all the The terms flying manually in this commercial aircraft in the world are article imply that the guidance func- established by the Authorities on tions have become unavailable, pos- the fundamental hypothesis that any sibly with the flight control laws in a qualified pilot is capable of meeting degraded mode. this requirement. In this configuration, pilots must be The pilot Specificities of flight control laws must anticipate to We have seen that the rules appli- the pilot must anticipate to a greater a greater extent cable for RVSM mean that the situa- extent the changes in the trajectories the changes in tions where the aircraft must be flown both vertically and horizontally. This is manually at high altitude are limited valid whatever the flight control law the trajectories to degraded cases, especially cases used, including the normal law. both vertically where the AP is lost and, possibly, The behaviour of the normal law and horizontally. where the normal law is also lost. As the aim of this article is to get a better differs from its behaviour at low alti- tude by the effect of the speed on knowledge of these situations, let us the trajectory. This is sufficient to look at the specificities of the high-al- make it worth the effort to become titude flight control laws. familiar with the situation in the sim- As said earlier, compared to low alti- ulator. For degraded laws, or for tude, the high aerodynamic speeds aircraft with conventional flight con- used at high altitude radically change trols, the characteristics specific to the trajectories followed for given load high altitude are more affected and factor applications. This means that must be known. Normal and alternate laws The normal law and the alternate law maneuvers, for a given longitudinal - so-called C* laws, or load factor stick order, give the same load factor flight control laws - function practically excursion. As the alternate law is not identically on the longitudinal axis as protected against excessive angles long as we remain within the opera- of attack, awareness of an approach tional flight envelope and we do not to limiting angle-of-attack is ensured perform dynamic maneuvers leading by the Stall Warning (SW) or, in cer- the angle-of-attack to approach max- tain cases, by the deterrent buffeting, imum values (which depend on the to which the pilot must react imme- Mach number). Beyond these limits, diately by releasing control. The SW the alternate law no longer ensures directly alerts the crew of stall proxim- the protections and this is recalled ity but it also indirectly alerts it by indi- by the protection lost message cating, during dynamic maneuvers, on the ECAM. The pull-out and turn that it is approaching angles of attack

45 Safety First #20 | July 2015 043 where the pitch-up phenomenon may altitude (around 4000 ft) below the start to develop; this phenomenon REC MAX altitude. itself can lead to stall if the pilot does not immediately counter it by reac- According to the type of aircraft and ting to the SW. In practice, maneu- type of failure, the alternate law may vers a little too dynamic can fairly lead to lateral control being in direct easily lead to the SW, especially if law, i.e. a deflection of the ailerons they are done close to the maximum according to the stick input and not cruise altitude (REC MAX) calculated according to a roll rate law, as is nor- by the FMS. For this reason and to mally the case in normal law. This make flying more comfortable, even difference can be fairly significant, outside of the RVSM space, when generally leading to roll responses a flying in degraded laws, it is recom- little more sharp than in normal law, mended to maintain some margin in but still easy to control. Direct law In direct law, as its name implies, the less need to use the trim than at low controls give direct orders to the con- altitude. To make flying trol surfaces. In direct law, the aircraft becomes an old aircraft where no During flight tests, Airbus test pilots try to adjust the kinematics of the direct more comfortable, assistance is given to the pilot. The law to make it as placid as possi- even outside of longitudinal trim must be used to zero ble at high altitude in all the weight the RVSM space, forces on the stick and to balance the and CG ranges. The aim is to have longitudinal effects of the engines. enough authority to efficiently do the when flying in The ECAM and the Primary Flight basic maneuvers in the vertical and degraded laws, Display (PFD) remind us of this by the horizontal planes, but without trying USE MAN PITCH TRIM message. to do specifically dynamic maneu- it is recommended However, depending on the aircraft, vers. Here also, as with alternate law, to maintain some very basic yaw or roll dynamic sta- bilisation functions may be included the deterrent buffeting and/or the SW warn against excess angles of attack margin in altitude in the direct law. At high altitude, the taking into account, if applicable, a (around 4000 ft) trim law versus speed variations, pitch-up tendency. The same recom- below the REC and therefore the Mach number, is mendations also apply concerning very flat. Pilots should therefore the flight altitude. MAX altitude. not be surprised that there is much TRAINING FOR HIGH-ALTITUDE MANUAL FLYING Representativeness of simulators at high altitude The flight mechanics models used on the models supplied by the simula- the training simulators are established tors are very close to reality. However, based on specific tests conducted dur- two important limits exist and must be ing real flights. They generate what is known, which are the very high angles called the data package. These tests of attack and the representativeness of are long and many to obtain a model the cabin movements. very close to reality. As I have done several thousands of hours of tests 1) During flight tests, for each type of all sorts on simulators before doing of aircraft, hundreds of stalls are per- them in flight, I can confidently say that formed, beyond the SW and a little

46 GENERAL TOPIC High-altitude manual flying beyond the maximum lift coefficient can clearly have counterproductive Over the (Cl) to clearly identify the loss of lift. In training effects as the pilots then per- normal operating practice, the maximum Cl is exceeded ceive sensations contrary to what they by several angle-of-attack degrees, would experience in reality. This can domain of let us say four or five, but not more. be asserted based on a comparison commercial This means that all maneuvers on the between the basic rotation speed and simulator that go beyond these known acceleration parameters on the three flying, simulators values enter a domain where the re- aircraft axis (i.e. p, q, r, nx, ny, nz of are perfectly presentativeness of the model becomes the flight mechanics) with the same representative of erroneous. Therefore, the exercises on the simulator must not go further than parameters measured in the cockpit of a mobile simulator during somewhat reality and utmost the excursions leading to the reactions dynamic maneuvers. For this reason, confidence can be to the SW which, according to regu- during the flight tests, cockpit move- lations, are expected by the pilot. In ments are never used to fine tune the placed in them, for practice, not more than 3 seconds after flight controls knowing that the sensa- both low and high the appearance of the SW during a tions experienced are, essentially false, altitude manual dynamic maneuver in cruise. This obvi- ously concerns only the unprotected and can therefore seriously alter test pilots assessment of these. flight. laws. Clearly these two limits can be consi- 2) The movements of mobile simu- dered as such only when certification lator cockpits are intended to trick flight tests maneuvers are performed the sensory channels of the pilots to very close to if not beyond the li- make them believe that what they mits of the aircraft flight envelope. Over perceive corresponds to a real flight. the normal operating domain of com- This operates fairly well when the si- mercial flying, simulators are perfectly mulated movements remain low. Sim- representative of reality and utmost ply, let us say that the feelings are not confidence can be placed in them, for too false whilst the movements of the both low and high altitudes. For this aircraft are those that the Auto Pilot reason, flying in a simulator is the best would command. Whenever signifi- option for pilots to experience and cant dynamic movements are done, train for manual flying at any altitude. the feelings become very false and Some ideas for high-altitude manual flying training Simulation training exercises must of AP, FD and ATHR, return to alter- show pilots that at high altitudes and nate law. Keep level flight. Reduce high Mach numbers, it is very impor- Mach to alternate law limit (if appli- tant to adopt an especially calm, flex- cable). Do a turn with a bank angle ible flying attitude without aggressive- of 30 (that is 1.15 g) in level flight ness. At the same time, the exercises at constant Mach. Resume straight suggested here will allow pilots to line flight. Descent with engines at reinforce the necessary confidence in idle to first level outside of the RVSM themselves. To gain this competence, space, still at constant Mach. Tem- it is important that they do maneuvers porarily stabilise at REC MAX 4000 which go a little beyond those that ft, maintaining the Mach. Observe they may have to do in flight. Here are the response of the aircraft, resume several personal ideas of exercises to descent. reach this objective. Within the same frame of mind, others can of course be 2) Normal law, AP engaged, weight = proposed. MLW + 2 hours of fuel consumption, REC MAX altitude. Loss of AP, FD 1) Normal law, AP engaged, weight = and ATHR, return to direct law. Use MLW + 2 hours of fuel consumption, the trim. Keep level flight. Reduce REC MAX altitude and cruise Mach Mach to direct law limit (if applica- according to airline Cost Index. Loss ble). Make a turn with a bank angle

47 Safety First #20 | July 2015 045 of 25 (that is 1.1 g) in level flight at manual flying training. But, again as a constant Mach. Resume straight line passenger, I at the same time require flight. Descent with engines at idle to that these same pilots have all the first level outside RVSM space, still at manual flying skills that we have dis- constant Mach. Temporarily stabilise cussed and which they require to face at REC MAX 4000 ft, maintaining up to failure cases where the piloting the Mach. Observe the response of aids are no longer available, whether the aircraft, resume descent. at high or low altitude. These two requirements are contra- As a passenger, I would be very happy dictory only in appearance. Indeed, to fly with an airline which gives its even as is the case in many airlines, pilots the instruction to place them- the pilots are authorised to manually At high selves in the easiest situation at all times. Pilots should be instructed to fly aircraft under certain conditions. During commercial flights, they could altitudes and high use all the piloting aids placed at their never fly manually at high altitude due Mach numbers, it disposal to facilitate their tasks as far to the RVSM rules, or under degraded is very important to as possible. In practice, this perfectly flight control laws for obvious reasons, respectable policy leads the pilots to which deprives them of all knowledge adopt an especially almost never manually fly the aircraft, of the reactions of their aircraft under calm, flexible flying except on take-off for a short period these conditions. and for certain landings between the The only solution to cover this need is attitude without minima and the ground when auto- therefore the intensive use of training aggressiveness. matic landing is impossible. This simulators and this in perfect compli- means that the pilots of such an air- ance with the limits of their represent- line acquire or maintain almost no ativeness.

48 046 Safety First #20 | July 2015 ARTICLES PUBLISHED IN PREVIOUS SAFETY FIRST ISSUES Issue 19 Issue 18 Issue 17 January 2015 July 2014 January 2014 Tidy cockpit for safe flight Control your speed... at take-off Airbus Brake Testing Landing on contaminated Safe operations with composite Hard Landing, a Case Study runways aircraft for Crews and Maintenance Understanding weight Learning from the evidence Personnel & balance A320 Family cargo Containers/ Aircraft Protection during Washing Wind shear: an invisible enemy pallets movement and Painting to pilots? Parts Departing from Aircraft (PDA) Flight Data Analysis (FDA), a Predictive Tool for Safety Management System (SMS) Flying a Go-Around, Managing Energy Issue 16 Issue 15 Issue 14 July 2013 January 2013 July 2012 Performance Based The Golden Rules for Pilots Thrust Reverser Selection means Navigation: RNP and RNP AR moving from PNF to PM Full-Stop Approaches Airbus Crosswind Development Transient Loss of Communication Atlantic Airways: Introduction and Certification due to Jammed Push-To-Talk of RNP AR 0.1 Operations The SMOKE/FUMES/AVNCS A320 and A330/A340 Families Flight Crews and De-Icing SMOKE Procedure A380: Development of the Flight Personnel Working together Post-Maintenance Foreign Controls - Part 2 in Temporary Teamwork for Objects Damage (FOD) Prevention Preventing Fan Cowl Door Loss safe Skies Corrosion: Do not forget that you are not Low Speed Rejected Take-Off A Potential Safety Issue alone in Maintenance upon Engine Failure Late Changes before Departure

49 Safety First #19 | January 2015 047 Issue 13 Issue 12 Issue 11 January 2012 July 2011 January 2011 A320 Family / A330 Prevention Airbus New Operational What is Stall? and Handling of Dual Bleed Loss Landing Distances How a Pilot Should React in Front The Fuel Penalty Factor The Go Around Procedure of a Stall Situation The Airbus TCAS Alert Prevention The Circling Approach Minimum Control Speed Tests (TCAP) VMU Tests on A380 on A380 A380: Development of the Flight Automatic Landings Radio Altimeter Erroneous Values Controls - Part 1 in Daily Operation Automatic NAV Engagement at Facing the Reality of everyday Go Around Maintenance Operations Issue 10 Issue 9 Issue 8 August 2010 February 2010 July 2009 A380: Flutter Tests A320 Family: Evolution of Ground The Runway Overrun Prevention Operational Landing Spoiler Logic System Distances: A New Standard Incorrect Pitch Trim Setting at The Take-Off Securing Function for In-flight Landing Distance Take-Off Computer Mixability: Assessment Technical Flight Familiarization An Important Function Go Around Handling Oxygen Safety Fuel Spills During Refueling A320: Landing Gear Downlock Operations Situation Awareness and Decision Making

50 048 Safety First #20 | July 2015 ARTICLES PUBLISHED IN PREVIOUS SAFETY FIRST ISSUES Issue 7 Issue 6 Issue 5 February 2009 July 2008 December 2007 Airbus AP/FD TCAS Mode: A320: Runway Overrun New CFIT Event During Non A New Step Towards Safety FCTL Check after EFCS Reset on Precision Approach Improvement Ground A320: Tail Strike at Take-Off? Braking System Cross A320: Possible Consequence of Unreliable Speed Connections VMO/MMO Exceedance Compliance to Operational Upset Recovery Training Aid, A320: Prevention of Tailstrikes Procedures Revision 2 Low Fuel Situation Awareness The Future Air Navigation Fuel Pumps Left in OFF Position Rudder Pedal Jam System FANS B A320: Avoiding Dual Bleed Loss Why do Certain AMM Tasks Require Equipment Resets? Slide/raft Improvement Issue 2 Cabin Attendant Falling through the Avionics Bay Access Panel September 2005 in Cockpit Tailpipe or Engine Fire Issue 4 Issue 3 Managing Severe Turbulence Airbus Pilot Transition (ATP) June 2007 December 2006 Runway Excursions at Take-Off Operations Engineering Bulletin Dual Side Stick Inputs Issue 1 Reminder Function Trimmable Horizontal Stabilizer Avoiding High Speed Rejected Damage January 2005 Take-Offs Due to EGT Limit Pitot Probes Obstruction Exceedance on Ground Do you Know your ATC/TCAS A340: Thrust Reverser Unlocked Go Arounds in Addis-Ababa due Panel? Residual Cabin Pressure to VOR Reception Problems Managing Hailstorms Cabin Operations Briefing Notes The Importance of the Pre-flight Introducing the Maintenance Hypoxia: An Invisible Enemy Flight Control Check Briefing Notes A320: In-flight Thrust Reverser A320: Dual hydraulic Loss Deployment Terrain Awareness and Warning Airbus Flight Safety Manager Systems Operations Based on Handbook GPS Data Flight Operations Briefing Notes

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