Published May 2012 BEA

Published May 2012 Bea-Free PDF

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This report expresses the conclusions of the BEA on the circumstances and causes. of this serious incident, In accordance with Annex 13 to the Convention on International Civil Aviation and. with European Regulation n 996 2010 the investigation was not conducted so as to. apportion blame or to assess individual or collective responsibility The sole objective is. to draw lessons from this occurrence which may help to prevent future accidents. Consequently the use of this report for any purpose other than for the prevention. of future accidents could lead to erroneous interpretations. SPECIAL FOREWORD TO ENGLISH EDITION, This report has been translated and published by the BEA to make its reading. easier for English speaking people As accurate as the translation may be the. original text in French is the work of reference,F GLZU 22 July 2011. Table of Contents,FOREWORD 1,SYNOPSIS 3,1 HISTORY OF FLIGHT 3. 2 ADDITIONAL INFORMATION 6,2 1 Meteorological Conditions 6.
2 2 Weather Radar 6,2 3 High Angle of Attack 8, 2 4 Behaviour of the Aeroplane in the Longitudinal Plane 9. 2 5 Messages and Warnings 9,2 6 Personnel Information 11. 2 6 1 Captain 11,2 6 2 Copilot on duty at the time of the event 11. 3 LESSONS LEARNED AND CONCLUSION 12,3 1 Use of weather radar 12. 3 2 Aural Warnings 12,3 3 Monitoring of Flight Parameters and CRM 13.
3 4 Conclusion 15,4 RECOMMENDATIONS 16, 4 1 Training in Parameter Monitoring during Turbulence or Overspeed 16. 4 2 AP Disengagement Warning 16,4 3 Training in the Use of Weather Radar 17. 4 4 Absence of CVR Data for Incidents 17,APPENDIX 18. F GLZU 22 July 2011,f zu110722en,Date Aircraft, 22 July 2011 at 1 h 00 UTC 1 Airbus A340 313 registered F GLZU Except where. otherwise stated,Place Operator the times shown, In cruise at FL350 North Atlantic ocean Air France in this report.
near position 18N 060W are expressed in,Persons on board Universal Time. Type of flight Captain PF Coordinated, Public transport 2 co pilots PNF 11 cabin crew UTC. Scheduled international passenger flight 270 passengers. 1 HISTORY OF FLIGHT, Note The following elements are based on recorded data in the FDR and the direct access recorder. DAR as well as statements The event was not available on the cockpit voice recorder CVR. The crew took off from Caracas Maiquet a Sim n Bol var airport at 23 h 38 for Paris. Charles de Gaulle The captain was PF, At 23 h 52 climbing through FL180 the PF and the PNF both set the range of their. Navigation Display ND to 320 NM, Between 0 h 28 and 0 h 47 the PNF modified the range of his ND several times.
between 20 and 320 NM and then kept the latter adjustment The crew indicated. that the weather radar set to maximum gain and a tilt between 0 5 and 1 did not. detect any precipitation 2 The aeroplane was stable at FL350 in clear air and at a The gain and tilt. are not recorded, cruise Mach of 0 83 Autopilot AP n 1 and the auto thrust A THR were engaged. parameters The, The weather radar mode was set to WX crew remembered. without being able, At 1 h 00 min 24 point n 1 on Figure 1 about 2 NM after passing coordinates 18N to confirm with. 60W the aeroplane entered a zone of moderate turbulence The overspeed warning certainty that the. tilt was alternately, OVERSPEED was triggered 3 and the Master Warning warning light came on The. set between, crew stated that they were very surprised by this warning Mach reached 0 87 0 5 and 1.
operating Mach,MMO was 0 86,The OVERSPEED,warning was. triggered at,MMO 0 006 that is,Mach 0 866 During,the event the high. speed protection,was not activated,Figure 1 Vertical flight path. F GLZU 22 July 2011, At 1 h 00 min 27 point n 2 the PNF manually disengaged the AP by pressing the. takeover pushbutton on the side stick A pitch up input on the PNF s side stick going. as far as to stop was recorded for 6 seconds This input was accompanied by an input. to bank to the right then left The PNF stated that he did not remember these inputs. From the start of the pitch up input until point n 9 the high angle of attack protection. was activated several times see the detail of the activation periods in the appendix. At 1 h 00 min 28 Mach was 0 84 and the OVERSPEED warning ceased for 2 seconds. It reappeared again for one second and then disappeared again The aeroplane. climbed at a vertical speed of 1 950 ft min, At 1 h 00 min 30 the Master Warning warning light went off The crew selected a.
Mach of 0 76 for 3 seconds then 0 85, At 1 h 00 min 31 point n 3 the PF extended the speedbrakes Mach was 0 84 and. started to decrease 2 seconds later, The PF indicated that in the seconds that followed he switched on the lights and. noticed being in IMC and that there was precipitation He also indicated that he. turned round to put his meal tray on the seat behind him and to take the Public. Address handset to make a passenger and cabin crew announcement The handset. slipped from his hands The PNF recovered it and used it to make the announcement. At 1 h 00 min 32 the altitude went above 35 200 ft The crew stated that they did. not remember hearing the Altitude alert warning which is triggered if the current. altitude is 200 ft above the selected altitude Pitch attitude increased moving from. 3 to 9 in 5 seconds, At 1 h 00 min 37 point n 4 the speedbrakes started to retract automatically Pitch. attitude then varied between 8 and 10, At 1 h 00 min 44 point n 5 the aeroplane was at FL360 The speedbrakes were. retracted Pitch attitude increased to about 12 in 2 seconds The aeroplane continued. to climb and Mach decreased, The PF stated that he had noticed that the speed was low Shortly afterwards at.
1 h 00 min 47 the crew selected Mach 0 93 The aeroplane was still climbing with a. vertical speed which reached a maximum of 5 700 ft min The crew was not aware of. this The N1 s were at 100, At 1 h 00 min 48 the PF switched the range of his ND to 160 NM. At 1 h 00 min 53 the PNF pressed the Master Warning light Altitude was 36 900 ft. At 1 h 01 min 08 point n 6 while the aeroplane was at 37 950 ft in climb the PF. disengaged the A THR and moved thrust levers forward to the TO GA detent. At 1 h 01 min 17 point n 7 altitude reached maximum 38 150 ft Mach was 0 66. The PF stated that he noted with surprise that altitude was 38 000 ft and asked the. PNF if they were cleared for FL350,F GLZU 22 July 2011. At 1 h 01 min 42 while the aeroplane descended past 37 000 ft and the selected. altitude was 35 000 ft the PF pulled the altitude selection knob ALT knob which. engaged the OPEN DES longitudinal mode The PF stated that he wanted to order. the AP to re descend to FL350 but that nothing was displayed on the PFD 4 The The AP was still. indicated airspeed was 226 kt or 19 kt below VLS 5 The 2 flight directors FD then disengaged at. that moment, disappeared 6 point n 8 At the same time the PNF carried out transmissions for one. minute on HF1 with the New York en route control centre in order to inform them of selectable speed. the level bust and the turbulence encountered,When the flight. At 1 h 02 min 06 point n 9 the aeroplane descended past 36 520 ft The PF then directors FD are. engaged in OPEN, became aware of the disengagement of the AP and made a pitch down input on his DES mode with.
sidestick Pitch attitude began to decrease 2 seconds later the AP disengaged. and speed is, From 35 400 ft point n 10 the PF re engaged AP1 altitude stabilised at FL350 below VLS 2 kt the. point n 11 and A THR was re engaged automatic descent. speed protection is, At 1 h 25 min 38 an ACARS message received from the Air France OCC indicated that triggered The FD. then disengages, there was nothing visible 10 NM north of the 18N 60W position on the satellite photo and the cross. at 1 h 00 and that no clear air turbulence was forecast at that point either bars disappear. on the PFD An, The flight continued without further incident to Paris Charles de Gaulle airport aural triple. where the crew landed at 8 h 33 click warning,is triggered.
F GLZU 22 July 2011,2 ADDITIONAL INFORMATION,2 1 Meteorological Conditions. The data available to the crew did not show any significant phenomenon on the. route roughly as far as the middle of the Atlantic. However infra red satellite images obtained by the BEA from M t o France showed. the presence of isolated cumulonimbus of moderate intensity between 0 h 30 and. 1 h 30 in the area around point 18N 60W with the top situated at FL380 7 The According to. the M t o France, recorded trajectory showed that the aeroplane flew close by these clouds during the. Arp ge model,event valid on 22 July,Figure 2 Trajectory on IR image at 1 h 00. It should be noted that this type of isolated cloud in an inter tropical zone is beyond. forecasting abilities other than immediate or very short term forecasts. The crew of another Air France flight about 40 minutes behind F GLZU at the same. level FL350 and on a virtually parallel route was able to look for then observe a. series of echoes in this zone,2 2 Weather Radar, F GLZU was equipped with Rockwell Collins weather radar The radar image obtained. depends on 3 parameters the gain the tilt angle between the horizontal and the. middle of the radar beam and the ND range The radar aperture is 1 7 above and. below the selected tilt, Weather radar is designed to detect water in liquid form rain or wet hail by.
measuring the rate of precipitation According to the rate detected and the selected. gain echoes of different colours are presented on the ND It hardly detects water in. solid form such as ice crystals or dry snow, The tilt adjustment determines the zone scanned by the radar beam and consequently. the echoes that are detected and displayed on the ND Adjustment of the gain then. enables the reflectivity of the precipitation encountered to be adapted It should be. noted that clouds situated in front of the aeroplane but not swept by the beam are. not visible on the radar,F GLZU 22 July 2011,Figure 3 Example of radar image. In addition the structure of cumulonimbus requires an adjustment of the tilt and. range as the aeroplane approaches a convective cell Indeed the reflectivity of. precipitation inside a cumulonimbus depends on the temperature. Figure 4 Cumulonimbus radar reflectivity, The most reflective zones liquid precipitation are located under ISO 0 C. The reflectivity is higher there, Between ISO 0 and ISO 40 C called radar top reflectivity is average and depends. on the liquid water ice crystals ratio, When the temperature is below 40 C the reflectivity is very low ice crystals.
On the day of the event the M t o France data indicated that the visible top of the. clouds corresponded to FL380 ISO 40 C at FL 330 and ISO 0 C at FL160. The tilt is adapted to the range of the ND The manufacturer s Flight Crew Training. Manual and the Air France FCOM A330 A340 manual recommend setting the range. in cruise to 160 NM or 80 NM, The FCTM indicates that in cruise the tilt must be set so that the ground returns only. appear within the most distant circles The same setting principle is covered in the Air. France FCOM manual for cruise above 20 000 ft, Neither of these 2 documents indicates explicitly the numerical values of tilt according Reference FOBN. FLT OPS ADV WX, to the range However an Airbus Flight Operations Briefing Note 8 indicates a range SEQ 07 REV. of magnitude of tilt values to use in cruise according to the range 02 FEB 2007. F GLZU 22 July 2011,Range of ND Tilt,320 NM 1 0,160 NM 1 5. The recorded data indicated that no return could have appeared on the PNF s ND. between 00 h 29 and 00 h 46 as the convective zone was beyond the ND range. After that calculations showed that a tilt set to 1 enabled in theory the appearance. of a return on the 2 ND until about 0 h 48 as the beam scanned the zone of increased. reflectivity Afterwards even with an adequate range the beam went further and. further from the zone of high reflectivity With a tilt set at 0 5 the possibility of a. return on the ND was low as the beam never crossed the zone of high reflectivity. 2 3 High Angle of Attack, In manual flying and normal operation conditions longitudinal control is performed.
according to the normal flight control law The pitch inputs on the sidestick. command the elevators and the THS to maintain a load factor according to the. sidestick travel With the sidestick in neutral wings horizontal the system maintains. a vertical load factor of 1 g in such a way that the trajectory is maintained constant. Adjustment of the THS is automatic, In normal law when the angle of attack exceeds a threshold called Alpha Prot the. elevator and THS control change to a protection mode where the angle of attack is. proportional to the position of the side stick The ordered angle of attack cannot. exceed a limit called Alpha MAX even if the sidestick is put into pitch up stop. position If the sidestick is released the angle of attack decreases and is maintained. at Alpha Prot, If the angle of attack becomes greater than Alpha MAX while the speedbrakes are. extended they then retract automatically, Furthermore the value of Alpha Prot depends on the Mach and the position of the. speedbrakes when the Mach increases as far as MMO 0 86 the value of Alpha Prot. The high angle of attack protection has priority over all other protections. the AP to re descend to FL350 but that nothing was displayed on the PFD 4 The indicated airspeed was 226 kt or 19 kt below VLS 5 The 2 flight directors FD then disappeared 6 point n 8 At the same time the PNF carried out transmissions for one minute on HF1 with the New York en route control centre in order to inform them of

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