Brief Description of the Occurrence
On August 3, 2016, a Boeing 777-300 of the Emirates Airlines Flight EK521 had a scheduled flight from Trivandrum, India, to Dubai, United Arab Emirates.
The flight was uneventful until it reached the landing phase of the flight (about to touchdown) at the Dubai International Airport. The aircraft crashed while landing at the Dubai International Airport. There were 282 passengers on board and 18 crew members. During the emergency evacuation, all 300 personnel, including crew members, survived the crash. However, a firefighter lost his life while rescuing the evacuating passengers. Two of the police officers also sustained minor injuries.
Investigation Agency on Emirates EK521
The UAE General Civil Aviation Authority, GCAA, was overall in charge of the investigation. Under the GCCA, an international investigation team led by the Air Accident Investigation Sector, AAIS, of the GCAA, and accredited representatives of the states of manufacture of the aircraft (United States), and the engines (United Kingdom) probed the cause of the accident of the Emirates Airline Boeing 777-300 aircraft flight EK521 at Dubai International Airport. Moreover, representatives of the Boeing Company, Rolls Royce, and Emirates Airlines acted as advisors to the investigators participating in the investigation.
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Details of the Investigation on Emirates EK521
While approaching the landing on Runway 12L, the Captain attempted to perform a tailwind manual landing. The onboard automatic terminal information service (ATIS) had already forecasted moderate wind shear warning affecting all runways at OMDB (ICAO code for Dubai International Airport). As a result of wind shear, the tailwind was imminent. However, it was within the allowable operational limitations of the aircraft.
Wind shear is a known weather phenomenon for pilots. It can actually make aircraft overrun or dump on the ground, especially in the case of tailwind. Although aircraft can manage the minor ones, if the minor ones are not taken care of properly, the results are catastrophic!
The decision to Go Around
The Captain decided to take a go-around, as he could not land the aircraft within the runway touchdown zone. Still considering wind shear not a serious problem, the Captain opts for a normal go-around. The flight crew initiated the standard flight crew operations manual (FCOM) Go-around and Missed Approach Procedure. The procedure involves pressing the TO/GA (Take off / GO Around) switch. The aircrew did the same.
How does the Aircraft Go-Around mechanism works?
The system is designed to activate the Autothrottle (A/T) system as soon as the TO/GA switch is pressed. However, as soon as the aircraft’s weight comes on the wheels, the TO/GA switch does not work. Subsequently, the autothrottle system also does not work. As a design feature, the TO/GA switches became inactive and did not affect the autothrottle (A/T). The aircrew later stated that they were not aware of the touchdown that lasted for six seconds.
While during all this Situation….
The aircraft climbed to a height of 85 ft radio altitude above the runway surface after getting airborne during the go-around attempt. Now the aircrew was highly engaged in the cockpit. They failed to observe that both thrust levers had remained at the idle position during all this situation. As a result, the engine thrust remained idle. It was natural that aircraft could not sustain the airlift due to lack of requisite thrust. The aircraft drastically lost its speed and quickly sank towards the runway as the airspeed was insufficient to support the climb.
When the aircraft had actually lost height and speed, the Captain initiated the wind shear escape maneuver procedure and rapidly advanced both thrust levers. But it was too late to act and to avoid the impact of the aircraft with Runway 12L.
What Happened Next?
Eighteen seconds after the initiation of the go-around, the aircraft impacted the runway. They slid on its lower fuselage along the runway surface for approximately 32 seconds, covering a distance of approximately 800 meters (2625 feet) before coming to rest. The aircraft remained intact during its movement along the runway, which actually protected the occupants. However, several fuselage-mounted components and the No.2 Engine/pylon assembly got separated from the aircraft due to the heavy impact and dragging of its fuselage and wing along the runway surface.
The Aircraft Ultimately Caught Fire
When the aircraft came to rest, the center wing tank exploded with a blast and caused a large section of the right-wing upper skin to be liberated. As the panel fell to the ground, it struck and fatally injured a firefighter. The aircraft was eventually destroyed due to subsequent fire.
The prime cause of the occurrence is attributed to the loss of situational awareness of the aircrew to handle a normal situation in the right manner. The aircrew failed to monitor the flight parameters (engine thrust) on time to take the prescribed procedure in the operator’s publications. They also omitted the engine thrust verification steps of the FCOM ̶ Go-around and Missed Approach Procedure.
Grey Areas discovered during the Investigation
- A very prominent grey area discovered during the investigation was that the aircrew seemed too much reliant on automation. They also seemed to be lacking training in flying go-arounds from close to the runway surface, with the TO/GA switches inactive.
- The handling of the situation by the aircrew was not appropriate, which significantly affected the flight crew’s performance in this critical phase of flight. This was a real-time situation, far different than the ones experienced during simulated training flights.
- This angle of the investigation also shows that the aircrew failed to take the right decision during the approach and landing as they were deprived of the situation at hand.
- Some systems-related discrepancies were also discovered during the investigation.
- The aircraft systems did not alert the flight crew that the TO/GA switches were inoperative when the Captain pushed the TO/GA switch with the AUTO throttle (A/T) was armed and active.
- The aircraft systems did not alert the flight crew to the inconsistency between the Aircraft configuration and the thrust setting necessary to perform a successful go-around.
- The Air traffic control did not pass essential information about wind shear reported by a preceding landing flight crew as a contributing factor. Two flights performed go-arounds after passing over the runway threshold.
- Although aviation has moved on to automation for major parts of its operations, including flying, the aircrew cannot rely completely on the aircraft systems. However, they are told to do so the same during their training. At some point, they are required to intervene effectively to handle a particular emergency.
- They must undergo rigorous SIM training. This training must prepare them to handle all possible emergencies in real-life situations. The reason being that system deficiencies are also highlighted when systems are used thoroughly for their redundancies.
- Aviation is a serious job apart from the fun side. Any carelessness of an insignificant nature can actually take many precious lives. Emirates EK521 was fortunate that none of the souls on board experienced death.