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Events from Jun 19th 1999 to Sep 19th 2020 www.avherald.com Incidents and News in Aviation List by: Filter: Accident: Emirates B773 at Dubai on Aug 3rd 2016, long landing, go around without thrust results in runway impact, aircraft on fire, TOGA switches inhibited

By Simon Hradecky, created Wednesday, Aug 3rd 2016 09:32Z, last updated Thursday, Feb 6th 2020 16:37Z An Emirates Airlines Boeing 777-300, registration A6-EMW performing flight EK-521 from Thiruvananthapuram (India) to Dubai (United Arab Emirates) with 282 passengers and 18 crew, was on final approach to Dubai's runway 12L at 12:41L (08:41Z) but attempted to go around after first ground contact. The aircraft however did not climb, but after retracting the gear touched down on the runway and burst into flames. All occupants evacuated via slides, 13 passengers received minor injuries, 10 were taken to hospitals, 3 treated at the airport. The aircraft burned down completely. A firefighter attending to the aircraft lost his life.



The airline reported: "Emirates can confirm that an incident happened at Dubai International Airport on 3rd August 2016 at about 12.45pm local time."



United Arab Emirates Government confirmed an Emirates aircraft arriving from India suffered a crash landing at Dubai Airport, all passengers have been evacuated, there are no reports of injuries.



United Arab Emirates General Civil Aviation Authority (GCAA) reported a firefighter attending to the fire, while saving lives, lost his own life. The director of the GCAA said: "I salute his ultimate sacrifice that kept many from harms way. Our thoughts and prayers are with his family."



Emirates Airlines' chairman reported 13 passengers received minor injuries during the incident and were treated by medical teams.



On Aug 4th 2016 the airline reported that both captain and first officer had accumulated more than 7000 flying hours. The aircraft involved in the "operational incident" was equipped with Trent 800 engines and had been delivered to the airline in March 2003.



A passenger in the aft cabin reported, that the approach was normal, there had been no announcements or indications of anything abnormal. Then there was a heavy impact, oxygen masks came down, the aircraft skidded shaking violently and immediately filling with smoke and came to a stop. All doors were opened, it appeared however not all of them were used for evacuation. After sliding down the chute the passenger began to run, about 100 meters from the aircraft an explosion was heard (editorial note: watch video "The aircraft erupting into flames", the right wing caught fire and including right hand engine separated from the aircraft).



Another passenger reported that the captain made an announcement they would land at Dubai and the weather was fine, nothing appeared to be amiss. Suddenly the aircraft hit the ground tail/belly first, at the same time the right hand engine caught fire, and the aircraft skidded to a halt, smoke filled the cabin, only at this time the passengers realised the seriousness of the situation. The accident came entirely out of the blue.



A ground observer reported EK-521 made a normal approach with the landing gear extended, touched down hard and went around, the gear was retracted, however the aircraft appeared to lack power and sank back onto the runway. (Editorial note: The Aviation Herald noticed the lack of a significant detail in the narration of passengers mentioned above, there was no mention of sounds of engines spooling up).



On Aug 8th 2016 a passenger reported in the reader comments on AVH below, that the approach was normal, the landing gear was down. The aircraft touched down, however, the nose was not lowered onto the runway and the aircraft appeared to climb away again, the gear was retracted, however, the engines did not spool up. The aircraft made ground contact again, skidded along the runway with the right hand engine separating from the aircraft but still being dragged along with the aircraft until the aircraft came to a full stop.



According to ATC recordings the aircraft performed a normal approach and landing, there was no priority or emergency declared. Upon contacting tower tower advised the crew to plan to vacate the runway at taxiway M9 and cleared the aircraft to land. Another approach reported on tower frequency. About 2 minutes after EK-521 reported on tower, the crew reported going around, tower instructed the aircraft to climb to 4000 feet, the crew acknowledged climbing to 4000 feet, a few seconds later tower instructs the next arrival to go around and alerts emergency services. The position of the aircraft is described near the end of the runway.



On Sep 6th 2016 United Arab Emirates' GCAA released their preliminary report reporting, that the aircraft landed long, both main gear struts touched down, the crew initiated a go-around, retracted the landing gear and climbed to 85 feet radar altitude with the speed decaying to 134 KIAS, the aircraft descended again with the landing gear in transit into the UP position, 3 seconds prior to impact with the runway the thrust levers were moved from IDLE to full forward and the authothrottle system transitioned from IDLE to THRUST mode, a second later a GPWS warning "DON'T SINK! DON'T SINK!" activated, another second later the engines began to respond, another second later the aircraft impacted the runway abeam N7 taxiway at 125 KIAS, 9.5 degrees nose up and a rate of descent of 900 fpm following by both engines contacting the runway surface, the landing gear still in transit towards the up position. The right hand engine pylon assembly separated from the wing, an intense fuel fed fire developed in the area of the separated engine pylon. The aircraft slid along the runway on its belly, left hand engine and outboard right hand wing, an incipient fire started at the underside of the left hand engine, and the aircraft came to a stop adjacent to the intersection with taxiway M13. A fire emanated from underneath the right hand engine, engine pylon area and fuselage. About a minute later the commander transmitted a Mayday Call and advised they were evacuating.



Fire fighters arrived about one minute after the aircraft came to a stop and began to immediately apply foam. All but two occupants evacuated the aircraft via inflated escape slides, the captain and a senior cabin crew member vacated the aircraft through the L1 door with a detached escape slide.



One cabin crew received serious, 21 passengers, another cabin crew and the first officer received minor injuries.



The aircraft was destroyed.



The GCAA reported the captain (34, ATPL, 7,456 hours total, 5,128 hours on type) was pilot flying, the first officer (37, ATPL, 7,957 hours total, 1,296 hours on type) was pilot monitoring. While descending towards Dubai the crew received ATIS reporting windshear on all runways. The aircraft was configured for a landing with flaps at 30 degrees, the Vapp was computed to 152 KIAS (Vref+5 knots). The aircraft performed an RNAV approach to runway 12L. Tower cleared the aircraft to land and reported the winds from 340 degrees at 11 knots and instructed the crew to vacate the runway via taxiway M9.



The aircraft descended through 1100 feet AGL with autothrottle engaged in SPEED mode at 152 KIAS, the wind began to change from a headwind of 8 knots to a tailwind of 8 knots. The autopilot was disconnected at 920 feet AGL, the approach continued with autothrottle engaged. Descending through 700 feet AGL at 154 KIAS the tailwind had gradually increased to 16 knots.



Descending through 35 feet AGL, at 159 KIAS, the captain initiated the flare, the autothrottle transitioned to IDLE and both thrust levers moved to the IDLE position. Descending through 5 feet AGL, at 160 KIAS, the tailwind changed to a head wind. About 5 seconds later the right main gear's weight on wheel sensors triggered about 1100 meters past the runway threshold followed by the left main gear's weight on wheel sensor 3 seconds after the right hand main gear, the nose landing gear remained airborne. The Runway Awareness Advisory System (RAAS) annunciated aurally "LONG LANDING, LONG LANDING".



4 seconds after the RAAS advisory the aircraft became airborne again in an attempt to go around in head wind, the flap lever was moved to 20 degrees and two seconds later the landing gear lever was moved to the UP position, the landing gear unlocked and began to retract.



5 seconds after the aircraft became airborne again tower instructed the flight crew to continue straight ahead and climb to 4000 feet. The instruction was correctly read back. Both flight crew members noticed the decaying speed, the first officer called "CHECK SPEED". The thrust levers were moved from IDLE to full forward, the autothrottle system transitioned from IDLE to THRUST mode.



The GCAA reported that the aircraft slid on the ground over 800 meters with the landing gear not yet in the fully up position.



Initially two fire tenders reached the aircraft and immediately began to foam the aircraft. After perceiving they had contained the fire the firemen assisted with the evacuation, two fire fighters laid out sideline hoses to cool the #2 engine. Other fire tenders arrived on scene without difficulties. After the initial two tenders ran out of water and all of the aircraft occupants had left the aircraft, the fire tenders moved to hydrants to refill. The two fire fighters, who had laid out the sidelines, were wrapping up the sidelines, when the aircraft's fuel center tank exploded killing one of the fire fighters.



Editorial notes: The preliminary report does not mention whether the TO/GA switches were pressed at the time of initiating the go around. However, the appendices of the preliminary report show a page out of the Flight Crew Operating Manual (see below) describing the go around procedure and stating: "The TO/GA switches are inhibited when on the ground and enabled again when in the air for a go around or touch and go."



On Aug 5th 2017 the GCAA released an interim statement reporting the investigation is ongoing. The GCAA stated: "Regarding the operation of the flight the Investigation is working to determine and analyze the human performance factors that influenced flight crew actions during the landing and attempted go-around. In addition, the Investigation has reviewed and has identified safety enhancements related to the validity of weather information that was passed to the flight crew, and communication between air traffic control and the flight crew. A detailed examination was performed of the Aircraft evacuation systems, including the operation of emergency escape slides in a non-normal aircraft resting position, and the effects of wind on the escape slides. A large number of aircraft systems were tested with the assistance of the manufacturers and analysis of the data downloaded indicates that there were no Aircraft systems or engine abnormalities up to the time of the Accident."



On Aug 9th 2018 the GCAA released a second interim statement stating: "An Annex 13 format draft final report has been issued which documents the details of findings, and cause and contributory factors to the Accident. Improvements identified in the areas of interest will be addressed to the concerned organizations as safety recommendations. Currently, the UAE GCAA Air Accident Investigation Sector, has started the draft final report review process in accordance with the AAIS internal procedures. A consultation review, as per Annex 13, will also involve the concerned State authorities, Emirates Airline and other organizations. Feedback to the draft final report will include comments and safety actions taken. The Final Report will be published after the AAIS has addressed the comments received by either amending the Report and/or appending disagreed comments."



Related NOTAM:

A1156/16 - AD CLSD. 03 AUG 11:20 2016 UNTIL 03 AUG 14:00 2016. CREATED: 03 AUG 11:18 2016



A1155/16 - AD CLSD. 03 AUG 10:00 2016 UNTIL 03 AUG 12:00 2016. CREATED: 03 AUG 10:07 2016



Metars:

OMDB 030900Z 11021KT 3000 BLDU NSC 49/07 Q0993 WS ALL RWY TEMPO 35015KT 1500

OMDB 030800Z 14012KT 100V180 6000 NSC 48/09 Q0994 WS ALL RWY TEMPO 35015KT 4000 DU

OMDB 030749Z 14012KT 110V180 6000 NSC 47/09 Q0994 WS ALL RWY TEMPO 35015KT 4000DU

OMDB 030700Z 06007KT 360V100 8000 NSC 44/10 Q0995 NOSIG

OMDB 030600Z 06005KT 350V100 8000 NSC 42/12 Q0995 NOSIG



Scenes inside the cabin during evacuation (Video: Keith Walker):

https://www.youtube.com/watch?v=nUg7zOBB3Ig



The last seconds of slide out after failed go-around:

https://www.youtube.com/watch?v=tl2qmZTQ9Mk



The aircraft erupting into flames (Video: Kazim Abbas):

https://www.youtube.com/watch?v=AyeqybkuW2A



Aerial overview of accident site:





The wreckage of A6-EMW after fire was extinguished (Photo: dotEmirates):





A6-EMW on fire at Dubai (Photo: Airport WebCams):





Page from FCOM describing go-around procedure (Graphics: GCAA):





Map (Graphics: AVH/Google Earth):









By Simon Hradecky, created Thursday, Feb 6th 2020 16:33Z, last updated Thursday, Feb 6th 2020 16:38Z



Causes



The Air Accident Investigation Sector determines that the causes of the Accident are:



(a) During the attempted go-around, except for the last three seconds prior to impact, both engine thrust levers, and therefore engine thrust, remained at idle. Consequently, the Aircrafts energy state was insufficient to sustain flight.



(b) The flight crew did not effectively scan and monitor the primary flight instrumentation parameters during the landing and the attempted go-around.



(c) The flight crew were unaware that the autothrottle (A/T) had not responded to move the engine thrust levers to the TO/GA position after the Commander pushed the TO/GA switch at the initiation of the FCOM ̶ Go-around and Missed Approach Procedure.



(d) The flight crew did not take corrective action to increase engine thrust because they omitted the engine thrust verification steps of the FCOM ̶ Go-around and Missed Approach Procedure.



Contributing Factors



The Investigation determines that the following were contributory factors to the Accident:



(a) The flight crew were unable to land the Aircraft within the touchdown zone during the attempted tailwind landing because of an early flare initiation, and increased airspeed due to a shift in wind direction, which took place approximately 650 m beyond the runway threshold.



(b) When the Commander decided to fly a go-around, his perception was that the Aircraft was still airborne. In pushing the TO/GA switch, he expected that the autothrottle (A/T) would respond and automatically manage the engine thrust during the go-around.



(c) Based on the flight crews inaccurate situation awareness of the Aircraft state, and situational stress related to the increased workload involved in flying the go-around maneuver, they were unaware that the Aircrafts main gear had touched down which caused the TO/GA switches to become inhibited. Additionally, the flight crew were unaware that the A/T mode had remained at IDLE after the TO/GA switch was pushed.



(d) The flight crew reliance on automation and lack of training in flying go-arounds from close to the runway surface and with the TO/GA switches inhibited, significantly affected the flight crew performance in a critical flight situation which was different to that experienced by them during their simulated training flights.



(e) The flight crew did not monitor the flight mode annunciations (FMA) changes after the TO/GA switch was pushed because:



1. According to the Operators procedure, as per FCOM ̶ Flight Mode Annunciations (FMA), FMA changes are not required to be announced for landing when the aircraft is below 200 ft;

2. Callouts of FMA changes were not included in the Operators FCOM ̶ Go-Around and Missed Approach Procedures.

3. Callouts of FMA changes were not included in the Operators FCTM Go-Around and Missed Approach training.



(f) The Operators OM-A policy required the use of the A/T for engine thrust management for all phases of flight. This policy did not consider pilot actions that would be necessary during a go-around initiated while the A/T was armed and active and the TO/GA switches were inhibited.



(g) The FCOM ̶ Go-Around and Missed Approach Procedure did not contain steps for verbal verification callouts of engine thrust state.



(h) The Aircraft systems, as designed, did not alert the flight crew that the TO/GA switches were inhibited at the time when the Commander pushed the TO/GA switch with the A/T armed and active.



(i) The Aircraft systems, as designed, did not alert the flight crew to the inconsistency between the Aircraft configuration and the thrust setting necessary to perform a successful go-around.



(j) Air traffic control did not pass essential information about windshear reported by a preceding landing flight crew and that two flights performed go-arounds after passing over the runway threshold. The flight crew decision-making process, during the approach and landing, was deprived of this critical information.



(k) The modification of the go-around procedure by air traffic control four seconds after the Aircraft became airborne coincided with the landing gear selection to the up position. This added to the flight crew workload as they attentively listened and the Copilot responded to the air traffic control instruction which required a change of missed approach altitude from 3,000 ft to 4,000 ft to be set. The flight crews concentration on their primary task of flying the Aircraft and monitoring was momentarily affected as both the FMA verification and the flight director status were missed.



The GCAA analysed the sequence of events:



The Aircraft was correctly configured for the area navigation (RNAV) approach to Dubai International Airport (OMDB). From 1,000 ft radio altitude and until the flare, the approach had been flown according to the stabilized approach criteria established by the Operator. The autopilot was disconnected at 930 ft radio altitude, the flight directors remained on, and the autothrottle (A/T) was armed and active as per the Operators policy for a manual landing.



The flight crew were prepared for a tailwind landing as per the wind information provided by the Tower as the Aircraft was descending through 1,000 ft radio altitude, approximately one minute before it passed over the runway threshold. ATC did not provide information to the UAE521 flight crew about windshear experienced by an aircraft that had landed prior to UAE521or about two previous go-arounds.



Elevated temperatures are common at OMDB during the month of August and the flight crew were familiar with these conditions as this was their home base. Over the Commanders flying experience on the B777 of approximately seven years, he had performed landings at OMDB in conditions of similar elevated temperatures. The runway surface temperature was recorded at 68 degrees centigrade.



Four seconds before the Aircraft passed over the runway 12L threshold, the flight crew were aware that the magnitude of the tailwind component decreased from 16 kt to 13 kt.



The Aircraft passed over the runway threshold (see figure 1 and Appendix E of this Report) at approximately 54 ft radio altitude, and 159 kt IAS, which was 7 kt above the approach speed (VREF30 + 5 kt). The airspeed was within the Operators stabilized approach criteria.



At approximately 40 ft radio altitude, 159 kt IAS, approximately 100 m beyond the threshold, a pull on the control column was recorded on the FDR. This was an indication of the Commanders intention to flare the Aircraft. Over the next 5 seconds, until 7 ft radio altitude, there was a steady increase in the Aircraft pitch angle from 0.4 to 2.6 degrees, with a corresponding decrease in the sink rate from approximately 700 ft per minute towards 350 ft per minute The flight crew were trained to refer to the automated radio altitude callouts during the approach as a prompt to commence the flare, which is normally initiated close to the THIRTY callout. As the initiation of the flare started earlier than recommended, this action most likely contributed to an increase in the landing distance. The flight crew training manual FCTM ̶ Flare and Touchdown, stated that the initiation of the flare occurs when the main gear is approximately 20 to 30 ft above the runway. The Commander had stated to the Investigation that he could not recall at what height the flare was initiated.



After the A/T had changed from SPEED to IDLE mode at 25 ft radio altitude, the airspeed decreased by 6 kt and was 153 kt at 10 ft radio altitude. As the Aircraft passed the runway aiming point and approximately 480 m beyond the threshold, the airspeed started increasing and at 2 ft radio altitude, it reached 165 kt IAS with the Aircraft approximately 840 m beyond the threshold. There was a 12 kt airspeed increase over approximately four seconds, during which time the groundspeed decreased by 5 kt, and the descent rate decreased from 432 ft per minute to 80 ft per minute. The airspeed increase was 18 kt above the landing reference speed of 147 kt VREF.



The flight crew did not notice the increase in airspeed as their attention was focused outside the Aircraft after the runway threshold was passed. This practice was in accordance with the FCTM ̶ Flare and Touchdown recommendation for the pilots to change their visual sighting point to the far end of the runway in order to control the pitch attitude during the flare.



The Investigation concludes that the 12 kt airspeed increase was due to a horizontal windshear as the wind shifted from a tail wind to a head wind component. The wind shift most likely occurred as the Aircraft was descending below 7 ft radio altitude as this was when the Commander first felt the Aircraft being affected by the environmental conditions of hot air raising from the runway surface and the wind shift. During this period, the Commander first exclaimed Oops followed by Thermals. The Commander made several inputs on the control column, control wheel and rudder in order to maintain wings level and keep the aircraft aligned with the runway centerline.



...



The additional lift created because of the increasing performance of the Aircraft contributed to the prolonged floating of the Aircraft over the runway. Even though the Commander was not aware of the increasing airspeed, he had responded to the increasing performance and in an attempt to land, three times made small pitch attitude corrections to lower the nose of the Aircraft. During this time, the Aircraft pitch angle decreased from 2.6 degrees to an average of 1.2 degrees between 5 ft and just prior to the touchdown.



The action taken by the Commander was in line with the recommendation of the FCTM ̶ Landing Flare Profile as it was stated that the touchdown body attitude (pitch angle), should be reduced by 1 degree for each 5 kt above the touchdown speed. For UAE521, the touchdown speed was calculated by the flight crew to be 147 kt (VREF30 + 0).



The FCTM ̶ Landing Flare Profile stated that the estimated time from the moment the flare is initiated until touchdown is between four to eight seconds depending on the approach speed. The Aircraft manufacturer training recommended that the flare should not be prolonged and the aircraft should be flown onto the runway in the normal touchdown range.



For UAE521 flight crew, they did not consider flare duration during the attempted landing. as it was not a requirement of the Operator.



As the Aircraft continued to float over the runway, it rolled to the left due to the wind effect and the Commander corrected with right control wheel input. This action caused the right main landing gear to contact the runway and untilt approximately 1,090 m beyond the threshold, approximately 10 seconds after the flare was commenced.



Approximately 2.5 seconds after the right main landing gear contacted the runway, the Commander had decided to go around and called Go-around. He stated that he felt that the Aircraft would not land even though he tried to lower the nose and that the Aircraft was towards the end of the touchdown zone.



He then initiated the flight crew operations manual (FCOM) Go-around and Missed Approach Procedure by pushing the left takeoff/go-around (TO/GA) switch a fraction of a second before an EGPWS long landing automatic cockpit annunciation occurred. The Commander and the Copilot stated that they were not aware that the right main landing gear had contacted the runway.



With the TO/GA switches inhibited because of the right main gear weight-on-wheels (WOW) [ground mode], pushing the TO/GA switch had no effect on the A/T mode. As designed, when the Commander pushed the left TO/GA switch, the FMA A/T mode remained at IDLE. As neither pilot had observed the FMA, they were not aware that the A/T mode had not changed to THR.



The Aircraft CVR analysis indicated that the first long landing annunciation occurred just after the Commander called Go-around, approximately 1,280 m beyond the threshold (380 m beyond the touchdown zone). This was 92 m further along the runway than the Operators programed long landing alert distance. The runway landing distance available after the first long landing annunciation was 2,320 m.



The FDR indicated a 1.4 degree movement of the No.1 engine thrust lever, which returned to the idle position in a fraction of a second. This movement of the thrust lever occurred just after both main landing gear untilted and the Aircraft transitioned to ground mode for the first time, approximately 1.5 seconds after the go-around command. The forward movement of the thrust lever was most likely caused when the Commander pushed the left thrust lever TO/GA switch. The Operator confirmed that this slight forward movement of the thrust lever can occur when the TO/GA switch is pushed. As the palm of the hand pivots on the thrust lever, the downward push of the TO/GA switch can cause the thrust lever to move forward slightly. Because the A/T mode was in IDLE this would have returned the thrust lever back to the idle thrust lever position.



After the go-around was initiated, both the left and right main landing gear completed two cycles of the air and ground modes, causing the speedbrake lever to partially deploy twice, each deployment lasting less than one second. On each occasion that the speedbrake lever deployed, it returned to the arm position. The Aircraft manufacturers post-Accident Performance Evaluation confirmed the two movements of the speed brake lever and stated that the speedbrake lever takes approximately 1.5 seconds to fully deploy from the arm to the up position. As the flight crews attention was focused outside the cockpit, they were unaware of the speedbrake lever movements.



When the Commander called for flaps 20, 2.5 seconds after the go-around command, both main landing gear were in ground mode, with the Aircraft pitch angle increasing towards 7.4 degrees. Although the flight crew stated that they were not aware that the Aircraft had touched down, the Commander was aware that the Aircraft was close to the runway and therefore he limited the pitch angle in order to avoid a tail strike.



From the initial contact of the right main landing gear with the runway until the Aircraft started to gain height for the go around, a distance of approximately 500 m was travelled in six seconds, with either one or both main landing gear in contact with the runway. The nose gear remained airborne throughout this period. As the Aircraft travelled along the runway, the airspeed decreased by 8 kt to 153 kt IAS.



The Aircraft continued into a headwind component of 8 kt, almost aligned with the runway centerline. With the headwind benefit, stowed speedbrake and the flaps still at the flaps 30 position, the Aircraft became airborne approximately 1,590 m beyond the runway threshold. Both main gear moved to the tilt position 3.7 seconds after the go-around initiation at an airspeed of approximately 153 kt IAS, 6 kt above VREF30. The Copilot confirmed flaps 20 as the Aircraft was climbing through 22 ft radio altitude.



According to the FCTM ̶ Rotation and Liftoff ̶ All Engines ̶ after rotation, with a normal take-off pitch (7 to 9 degrees) and take-off thrust, the aircraft will reach a height of 35 ft radio altitude in 2.5 seconds. A similar performance was attained by the Aircraft as it reached a height of 35 ft in two seconds at a vertical speed of 512 ft per minute, even though the engine thrust levers and EPR remained at idle.



The Operators Go-around and Missed Approach Procedure required both pilots to verify rotation to go-around attitude and that engine thrust was increasing, after the pilot monitoring selected flaps 20. The pilot monitoring was then required to verify that thrust was sufficient for the go-around and adjust as necessary.



As the procedure did not require a verbal announcement of these two verifications, it was not possible for either crewmember to identify that the other crewmember had omitted these actions. Thus, the opportunity to identify an omitted action by a crewmember was lost and the need to take immediate recovery action and rapidly increase engine thrust was not identified.



The Copilot called Positive climb 1.5 seconds after confirming flaps 20, when the Aircraft vertical speed was approximately 592 ft per minute, and the airspeed was decreasing towards 147 kt IAS. The Copilots call was followed by the Commanders call for gear-up,

four seconds after the Aircraft became airborne. The airspeed continued to decrease and was 145 kt IAS at 58 ft radio altitude with the pitch angle increasing towards 8.4 degrees.



During the time between the Commanders gear up call and the Copilots landing gear lever selection to up, the Tower contacted UAE521 and issued, over a period of about three seconds, a modified missed approach altitude and heading instruction. Just after the Copilot read back the Tower instruction correctly, the Aircraft reached its maximum height above the runway of 85 ft radio altitude with the airspeed at 131 kt IAS. The Copilot selected the new altitude of 4,000 ft in the MCP as the Aircraft started to sink. The Copilot did not check that the flight director was on after selecting the landing gear lever to up as required by the Go-Around and Missed Approach Procedure.



Less than 12.5 seconds from the time that the TO/GA switch was pushed, the Aircraft had insufficient energy remaining to gain further height. The energy loss was aggravated by the landing gear doors opening.



The Aircraft loss of airspeed was perceived by the Commander as a windshear effect, which prompted him to call Windshear TOGA. The sink rate was increasing towards 500 ft per minute as the Aircraft sank below 67 ft radio altitude with the airspeed decreasing below 130 kt IAS. Soon after, the Commander pushed the TO/GA switch and manually advanced both thrust levers fully forward, as per the Operators windshear escape maneuver procedure. Only at this time did the Commander realize that the engines were not producing sufficient thrust.



Eighteen seconds after the initiation of the go-around the Aircraft impacted runway 12L approximately 2,530 m beyond the runway threshold. The Aircraft was controllable until impact, but the height available was insufficient to prevent impact with the runway.



The Aircraft manufacturers post-Accident Performance Evaluation calculated that, as the Aircraft gained height, at approximately 58 ft radio altitude when the landing gear lever was selected to the up position, a successful go-around could have been flown had the thrust levers been advanced to go-around thrust by the A/T, or immediately by manual advancement of the thrust levers, and had the pitch been maintained at go-around pitch. The performance analysis indicated that as the engines accelerated, the Aircraft would lose some height but would clear the runway at a minimum height of 17 ft radio altitude before safely climbing away. This hypothetical recovery scenario was possible, had the UAE521 flight crew been auh of the Aircraft state, which was not the case.



The Investigation concludes that the Commander maintained the stabilized approach criteria established by the Operator during the attempted tailwind landing. However, the landing distance was increased due to the early flare, the updraft created by the thermals rising from the runway surface and flight in ground effect which caused the Aircraft to remain airborne beyond the FCTM recommended touchdown of between 305 m to 610 m. Beyond this point, the Aircraft entered a performance increasing windshear as the wind shifted to a headwind. The Copilot, as the pilot monitoring, did not observe that the Aircraft airspeed was increasing as it descended below 7 ft radio altitude and that it had reached 165 kt at 2 ft radio altitude.



The Investigation concludes that the Commanders decision to go-around was because he was unable to land the Aircraft within the touchdown zone. His decision was in line with the Operators policy and was based on his perception that the Aircraft would not land due to thermals and was not due to a windshear encounter. For this reason, the Commander elected to fly a normal go-around and not to fly the windshear escape maneuver.



Because the Commander was not aware that the Aircraft had touched down and that the TO/GA switches were inhibited, he relied on the Aircraft automation when he pushed the TO/GA switch based on his training for the initiation of a normal go-around. His perception, as well as that of the Copilot, was that the Aircraft was airborne when he pushed the TO/GA switch. However, neither pilot had monitored the engine thrust and Aircraft performance as required by the Go-Around and Missed Approach Procedure. By the time the loss of airspeed was recognized, the actions taken in executing the windshear escape maneuver were too late to avoid impact with the runway.



The GCAA continued analysis:



As designed, the B777 crew alerting system provides cockpit alerts to warn the flight crew of an aircraft configuration inconsistency during the takeoff, landing and go-around after touchdown phases. However, for a go-around aircraft configuration that is inconsistent with the maneuver, no alert is provided to the flight crew.



When the UAE521 Commander pushed the TO/GA switch, the Aircraft pitch angle started to increase towards 7 degrees. The air/ground system transitioned to air mode, and the Aircraft started to climb. The speedbrake lever automatically returned to the arm position and the flaps retracted from flaps 30 to flaps 20 as commanded by the Copilots movement of the flap lever. The vertical speed changed from descent to climb and the landing gear was transitioning to the up position. During this time, the airspeed continued to have a decreasing trend. As identified in the post-Accident Aircraft manufacturers Performance Evaluation, the Aircraft could have safely performed a go-around up to and including the time when the landing gear was selected to up had the TO/GA switch been pushed and/or the engine thrust levers been manually advanced to achieve go-around thrust.



Analysis of the EEC data by the engine manufacturer indicated that the EEC was responding to the Aircraft status during the go-around. Both engine idle speeds had stabilized at low idle and as the Aircraft started to climb above 5 ft radio altitude, the EEC changed from ground to flight status and commanded the engines to high idle. The EEC continued to adjust the idle speed as flaps 20 was selected and when the landing gear lever was selected to up.



The Investigation concludes that the Aircraft configuration changes that were occurring after the Aircraft became airborne, together with the decreasing airspeed trend, was sufficient for the Aircraft systems to identify that the Aircraft was in an incorrect configuration for the attempted go-around maneuver. However, the crew alerting system was not designed to give a configuration warning for a go-around with the engine thrust levers not advancing towards the TO/GA position.



The GCAA analysed:



TO/GA switch inhibit information



The Operators training program for the B777 was based on the Aircraft manufacturer and FAA-approved training program, which did not include the TO/GA inhibit logic.



The Operators OM-A policy, as well as the Aircraft manufacturers recommendation, is for pilots to use the A/T for all phases of flight, including all normal go-arounds. However, when the A/T is controlling engine thrust, the TO/GA switch inhibit logic characteristics were not clearly demonstrated to the pilots. The exceptions to this policy are when there is a procedural action that requires the A/T to be disconnected, or when the A/T is unserviceable. Under either situation, pilots are made aware that manual intervention is required for any thrust changes.



Both the Commander and the Copilot had attended the initial computer-based training (CBT) for the B777. However, the CBT did not cover TO/GA switch inhibiting or FMA changes caused by a go-around initiated after the TO/GA switches became inhibited.



Neither the Commander nor the Copilot had a complete understanding of the TO/GA switches and they were not made aware during their training that the TO/GA switches become inhibited when the radio altitude is less than 2 ft for a time greater than three seconds prior to touchdown. The Operators crew resource management manual stated:



The major problem that has been identified with automation is due to a lack of understanding. If we do not fully understand the system, we are not able to anticipate the system response or evaluate its performance.



Therefore, based on his incorrect perception that the Aircraft had not yet touched down, the UAE521 Commander would have expected the A/T to be available when the TO/GA switch was pushed. In fact, the Aircraft had touched down and the TO/GA switch was pushed 2.5 seconds after touchdown.



The FCTM stated that if a go-around is initiated by pushing either TO/GA switch before the aircraft touches down, the A/T applies go-around thrust and the go-around would continue. It is then required to observe that the A/T provides go-around thrust, or to manually apply go-around thrust when the aircraft rotates to the go-around attitude.



The GCAA analysed that fatigue and cockpit authority gradient did not play any role in the accident.



The GCAA analysed passenger behaviour with respect to evacuation:



Before the seat belt sign was turned off, passengers started to stand up. The cabin crew, who had been instructed to attend to their stations, were prevented by passengers in the aisles from moving into the cabin and addressing passengers directly. Instead, the passenger address system was used in an attempt to have the passengers remain seated.



By the time the Commander ordered the evacuation, one minute had elapsed since the Aircraft had come to a stop. During this one minute, time was spent by the flight crew in locating the emergency checklist which had been scattered with other loose items in the cockpit as a result of the impact. Before the evacuation command, some passengers left their seats to retrieve their belongings from the overhead bins. These passengers blocked the aisles and passages to the exits. It was difficult for the cabin crewmembers to keep the passengers seated before the evacuation was commanded and by that time the cabin had started to fill with smoke, the Aircraft was visibly damaged, and the external fire had started and was visible to some passengers.



Expediting the evacuation command could have attracted the attention of passengers at an early stage and reduced the opportunity for passengers to gather their belongings. A readily accessible evacuation checklist is a key factor in facilitating an expeditious evacuation command.



Graphics of flight data (Graphics: GCAA):



On Feb 6th 2020 the GCAA released their final report concluding the probable causes of the accident were:The GCAA analysed the sequence of events:The GCAA continued analysis:The GCAA analysed:The GCAA analysed that fatigue and cockpit authority gradient did not play any role in the accident.The GCAA analysed passenger behaviour with respect to evacuation:Graphics of flight data (Graphics: GCAA):

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