If you wish to contribute or participate in the discussions about articles you are invited to join SKYbrary as a registered user

 Actions

B773, Dubai UAE, 2016

From SKYbrary Wiki

Summary
On 3 August 2016 the crew of a Boeing 777-300 rejected a landing at Dubai after a touchdown beyond the TDZ was followed by an automated 'LONG LANDING' Advisory Callout. Four seconds later, the aircraft became airborne again but with the thrust at Idle, it reached approximately 85 feet above the runway before sinking back onto it and impacting rear fuselage first at 900 fpm. The right engine-pylon assembly detached and an intense fuel-fed fire started as the aircraft came to a stop and it was quickly destroyed by impact and fire. All 300 occupants escaped, 23 with minor injuries.
Event Details
When August 2016
Actual or Potential
Event Type
Fire Smoke and Fumes, Loss of Control, Runway Incursion
Day/Night Day
Flight Conditions VMC
Flight Details
Aircraft BOEING 737-300
Operator Emirates
Domicile United Arab Emirates
Type of Flight Public Transport (Passenger)
Origin Trivandrum International Airport
Intended Destination Dubai International Airport
Take off Commenced Yes
Flight Airborne Yes
Flight Phase Missed Approach
APR
Location - Airport
Airport Dubai International Airport
General
Tag(s) Deficient Crew Knowledge-automation
FIRE
Tag(s) Post Crash Fire
HF
Tag(s) Inappropriate crew response (automatics),
Manual Handling,
AP/FD and/or ATHR status awareness
EPR
Tag(s) Emergency Evacuation,
Slide Malfunction
Safety Net Mitigations
TAWS Available but ineffective
TAWS with RAAS Available but ineffective
Outcome
Damage or injury Yes
Aircraft damage Hull loss
Non-aircraft damage Yes
Injuries Few occupants
Investigation Type
Type Independent

Description

On 3 August 2016, a Rolls Royce Trent 892-powered Boeing 777-300 (A6-EMW) being operated by Emirates on a scheduled international passenger flight from Trivandrum, India to Dubai as EK 521 attempted to commence a go around after touchdown on runway 12 at destination in day VMC but almost immediately sank back onto the runway and veered to the right before stopping. All 300 occupants escaped but one member of the cabin crew was seriously injured and 21 passengers, one of the pilots and another member of the 16-strong cabin crew sustained minor injuries. The aircraft was completely destroyed by impact damage and an intense fire which followed. One fire fighter was killed by an explosion which occurred after the evacuation to safety of all the passengers and most of the crew. Damage was caused to the runway surface and to manoeuvring area lighting and signage.

Investigation

An Investigation is being carried out by the UAE GCAA Air Accident Investigation Sector. Both the DFDR and the CVR were recovered from the wreckage in a heat-damaged condition but were successfully downloaded for the Investigation by the UK AAIB.

It was noted that the 34 year-old Captain had accumulated 7,457 total flying hours including 5,128 on type and had previously flown the Airbus A330/A340 as a First Officer. The 37 year-old First Officer had accumulated 7,957 total flying total hours of which 1,296 were on type.

It was established that the Captain had been PF and that the aircraft had been radar vectored for an RNAV/GNSS approach to runway 12L with flap 30 set. Landing Clearance was accompanied by a spot wind of 340° 11 knots. DFDR data showed that the AP had been disengaged at approximately 920 feet agl and that the A/T had remained engaged in SPEED mode until automatically transitioning to IDLE mode as the flare to land was commenced. The right MLG was recorded as touching down approximately 1100 metres into the available LDA of 3600 metres at 15 knots above the applicable Vref. The left MLG followed 3 seconds later, one second after the RAAS aural alert 'LONG LANDING' had been annunciated. Four seconds after that, the aircraft became airborne again "in an attempt to go around" and ATC cleared the aircraft to climb straight ahead to 4,000 feet which was correctly acknowledged. Four seconds after becoming airborne, Flaps 20 was selected followed 2 seconds late by selection of the Landing Gear Lever to 'UP'. With the landing gear in transit and the thrust still at IDLE, the aircraft reached a maximum height of approximately 85 feet agl before it began to sink back onto the runway. Three seconds before impact occurred, the thrust levers were advanced to full forward and the A/T changed from IDLE mode to THRUST mode. Two seconds before impact, an EGPWS Mode 3 DON'T SINK' Alert was annunciated.

DFDR data showed that rear fuselage impact occurred first at a recorded rate of descent of 900 fpm, a nose up pitch attitude of 9.5° and a forward speed of 125 KCAS some 2,530 metres from the beginning of the runway. For the next 32 seconds, the aircraft slid along the runway for approximately 800 metres before veering off the to the right, rotating through 120° and stopping with the No 2 engine/pylon assembly detached and near the right wingtip. Fire was already evident "on the detached No.2 engine, the damaged No 2 engine-pylon attachment area, the underside of No.1 engine and from under the aircraft fuselage".

The initial impact point (1) and the ground track to the final stopping position (2). [Reproduced from the Official Report]

Once the aircraft had stopped, the Captain made a PA "Attention Crew at Stations" followed shortly afterwards by a command to evacuate the aircraft. First Class was unoccupied, 13 of the 42 seats in Business Class and 269 of the 310 seats in Economy Class were occupied. The evacuation used only 5 of the 10 passenger cabin emergency exits. The two over wing exits remained closed due to smoke and fire outside, three other slides were not used - one detached from the aircraft when deployed and two others could not be used because the wind blew the slide up against the door.

Of the five exits which were used:

  • The slide at one was lifted off the ground by the wind but one of the RFFS personnel held it down and it was then used,
  • The slide at another was used initially but deflated after being used by "several passengers",
  • One exit could not be used until "the smoke cleared",
  • Another exit was initially used by "several passengers" but "they became stuck on the slide because it was filled with firefighting water",
  • A fifth exit was used by "some passengers" but "towards the end of the evacuation, the wind blew the slide up against the door preventing further evacuation”.

By the time the centre fuel tank explosion occurred, which killed an attending firefighter, 9 minutes after the aircraft had come to a stop, only the Captain and the Senior Cabin Crew Member were still on board searching the cabin for any remaining passengers. The explosion caused intense smoke to fill the whole aircraft and they both tried to evacuate from the flight deck emergency window exits but were unable to use those exits as they were unable to locate the evacuation ropes. They both left the aircraft by jumping from the L1 door onto the inflated slide which had detached when the door had opened and was laying on the ground below the door. Following the explosion, "the dynamics of the fire altered with the fire migrating into the interior of the Aircraft cabin, and at a later stage, into the cargo compartments" leading to the complete destruction of the aircraft.

The documented Flight Crew Procedures for a go around initiated after touchdown were examined and the following noted:

  • The FCTM was found to state that "an automatic go around cannot be initiated after touchdown". It also states that "As thrust levers are advanced auto speedbrakes retract and autobrakes disarm. The F/D go-around mode will not be available until go-around is selected after becoming airborne".
  • The FCOM description of a go around initiated after touchdown states that the TO/GA switches are inhibited when on the ground and enabled again when in the air for a go around. It then states that the first push of the TO/GA switches once airborne will command the A/T to change from IDLE mode to THRUST mode and set sufficient thrust to establish a minimum 2000 fpm rate of climb.
  • The FCOM Go-Around and Missed Approach Procedure requires that the PF pushes the TO/GA switch and calls 'FLAPS 20' then verifies that "rotation to go around attitude" and "thrust increase" occurs; the PM set the requested flap and then "verify that the thrust is sufficient for the go around". These actions must then be followed by a PM call of 'Positive Climb' after verification of this on the altimeter and a PF call of 'Gear Up' once they have checked positive climb on their own altimeter.

The remainder of the Investigation into the Accident "will carry out in-depth analysis of Contextual factors, Human factors and Organisational factors".

The Preliminary Report on which this summary is based was issued on 5 September 2016.

Related Articles