UAE Civil Aviation Authority releases preliminary report on Emirates EK521 accident

Emirates Boeing 777-300ER
Tis Meyer/

The Air Accident Investigation Sector (AAIS) of the General Civil Aviation Authority (GCAA) has issued a Preliminary Report on the accident involving Emirates flight EK521.

On 3 August 2016, an Emirates Boeing 777-300 Aircraft, registration A6-EMW, operating a scheduled passenger flight EK521, departed Trivandrum International Airport (VOTV), India at 0506 for Dubai International Airport (OMDB), the United Arab Emirates.

At approximately 0837, the Aircraft impacted the runway during an attempted go-around at Dubai.

There were a total of 300 people onboard the Aircraft, comprising 282 passengers, two flight crewmembers, and 16 cabin crewmembers.

The Commander, seated in the left hand seat, was the pilot flying, and the Copilot was the pilot monitoring.

As the flight neared Dubai, the crew received the automatic terminal information service (ATIS) Information Zulu, which included a windshear warning for all runways.

The Aircraft was configured for landing with the flaps set to 30, and approach speed selected of 152 knots (VREF + 5) indicated airspeed (IAS) The Aircraft was vectored for an area navigation (RNAV/GNSS) approach to runway 12L. Air traffic control cleared the flight to land, with the wind reported to be from 340 degrees at 11 knots, and to vacate the runway via taxiway Mike 9.

During the approach, at 0836:00, with the autothrottle system in SPEED mode, as the Aircraft descended through a radio altitude (RA) of 1,100 feet, at 152 knots IAS, the wind direction started to change from a headwind component of 8 knots to a tailwind component. The autopilot was disengaged at approximately 920 feet RA and the approach continued with the autothrottle connected. As the Aircraft descended through 700 feet RA at 0836:22, and at 154 knots IAS, it was subjected to a tailwind component which gradually increased to a maximum of 16 knots.

At 0837:07, 159 knots IAS, 35 feet RA, the PF started to flare the Aircraft. The autothrottle mode transitioned to IDLE and both thrust levers were moving towards the idle position. At 0837:12, 160 knots IAS, and 5 feet RA, five seconds before touchdown, the wind direction again started to change to a headwind.

As recorded by the Aircraft flight data recorder, the weight-on-wheels sensors indicated that the right main landing gear touched down at 0837:17, approximately 1,100 meters from the runway 12L threshold at 162 knots IAS, followed three seconds later by the left main landing gear. The nose landing gear remained in the air.

At 0837:19, the Aircraft runway awareness advisory system (RAAS) aural message “LONG LANDING, LONG LANDING” was annunciated.

At 0837:23, the Aircraft became airborne in an attempt to go-around and was subjected to a headwind component until impact. At 0837:27, the flap lever was moved to the 20 position. Two seconds later the landing gear lever was selected to the UP position. Subsequently, the landing gear unlocked and began to retract.

At 0837:28, the air traffic control tower issued a clearance to continue straight ahead and climb to 4,000 feet. The clearance was read back correctly.

The Aircraft reached a maximum height of approximately 85 feet RA at 134 knots IAS, with the landing gear in transit to the retracted position. The Aircraft then began to sink back onto the runway. Both crewmembers recalled seeing the IAS decreasing and the Copilot called out “Check speed.” At 0837:35, three seconds before impact with the runway, both thrust levers were moved from the idle position to full forward. The autothrottle transitioned from IDLE to THRUST mode. Approximately one second later, a ground proximity warning system (GPWS) aural warning of “DON’T SINK, DON’T SINK” was annunciated.

One second before impact, both engines started to respond to the thrust lever movement showing an increase in related parameters.

At 0837:38, the Aircraft aft fuselage impacted the runway abeam the November 7 intersection at 125 knots, with a nose-up pitch angle of 9.5 degrees, and at a rate of descent of 900 feet per minute. This was followed by the impact of the engines on the runway. The three landing gears were still in transit to the retracted position. As the Aircraft slid along the runway, the No.2 engine-pylon assembly separated from the right hand (RH) wing. From a runway camera recording, an intense fuel fed fire was observed to start in the area of the damaged No.2 engine-pylon wing attachment area. The Aircraft continued to slide along the runway on the lower fuselage, the outboard RH wing, and the No.1 engine. An incipient fire started on the underside of the No.1 engine.

The Aircraft came to rest adjacent to the Mike 13 taxiway at a magnetic heading of approximately 240 degrees. After the Aircraft came to rest, fire was emanating from the No. 2 engine, the damaged RH engine-pylon wing attachment area and from under the Aircraft fuselage. Approximately one minute after, the Commander transmitted a “MAYDAY” call and informed air traffic control that the Aircraft was being evacuated.

Together with the fire commander, the first vehicle of the airport rescue and firefighting service (ARFFS) arrived at the Accident site within one minute of the Aircraft coming to rest and immediately started to apply foam. Additional firefighting vehicles arrived shortly after.

Apart from the Commander and the senior cabin crewmember, who both jumped from the L1 door onto the detached slide, crewmembers and passengers evacuated the Aircraft using the escape slides.

Twenty-one passengers, one flight crewmember, and one cabin crewmember sustained minor injuries, and a second cabin crewmember sustained a serious injury. Approximately nine minutes after the Aircraft came to rest, a firefighter was fatally injured as a result of the explosion of the center fuel tank.

Detail of injuries

The Copilot suffered abrasions to his elbow. The senior cabin crewmember required medical treatment and was hospitalized for five days as a result of smoke inhalation. A cabin crewmember, who evacuated using the R2 door escape slide, sustained blisters to her feet that required medical treatment.

Out of the 282 passengers, 21 suffered minor injuries and were transported to different medical facilities.

A firefighter from the ARFFS sustained fatal injuries during firefighting activity, and eight firefighters required medical treatment for minor injuries.

Flight recorders

During the Aircraft recovery, both flight recorders were found in the rear galley area but still attached to the original mounting trays, with signs of prolonged exposure to elevated temperatures. The damaged flight recorders were sent to the AAIB facility for data retrieval in the presence of AAIS investigators.

Both memory modules were removed from the recorders. Optical microscope examinations were performed on the memory modules including the recovery of the memory unit information cables, prior to performing the download and readout. After the serviceability of the memory modules had been established, they were attached to a new chassis allocated for each recorder in order to download the data. Data from the DFDR and CVR was successfully downloaded and read out.

The examination of the DFDR and the CVR data showed that the recorders continued to record for a short period after the runway impact. The Investigation found that this portion of the recorded data was either invalid or missing information.

Impact information

The point of impact of the Aircraft with the runway was approimately 2,530 meters from runway 12L threshold, adjacent to the November 7 taxiway. Marks on the runway indicated that the Aircraft slid for approximately 800 meters along the runway with the three landing gears not fully up. The Aircraft came to rest adjacent to the Mike 13 taxiway, having turned to the right onto a heading of
approximately 240 degrees.

The Aircraft aft fuselage lower section impacted first, followed by the engines, the lower section of the aircraft belly fairing, and then the forward fuselage and nose landing gear doors. The No.2 engine separated, moved laterally on the right wing leading edge, and remained near the right wingtip until the Aircraft came to rest.

As it slid along the runway surface, various components detached from the Aircraft. These components included portions of the engine cowlings, secondary support structures and parts of the wing to body fairings, access panel doors, and systems components.

When the Aircraft came to rest, the primary structure was intact with the exception of the No.2 engine-pylon assembly which had separated from the RH wing attachment.

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