Accident Boeing 777-222 N796UA,
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Date:Wednesday 29 July 1998
Type:Silhouette image of generic B772 model; specific model in this crash may look slightly different    
Boeing 777-222
Owner/operator:United Airlines
Registration: N796UA
MSN: 26931/112
Year of manufacture:1998
Fatalities:Fatalities: 0 / Occupants: 289
Aircraft damage: Substantial
Location:London Heathrow Airport (LHR/EGLL) -   United Kingdom
Phase: Initial climb
Nature:Passenger - Scheduled
Departure airport:London Heathrow Airport (LHR/EGLL)
Destination airport:San Francisco, California (SFO/KSFO)
Investigating agency: AAIB
Confidence Rating: Accident investigation report completed and information captured
Made emergency landing back at London Heathrow Airport 29-7-1998 due to smoke in the cockpit and cabins following a suspected engine fire during the initial climb phase. No injuries sustained to the 289 persons on board (17 crew and 272 passengers). According to the following excerpt from the official AAIB report into the accident:

"The aircraft, with 17 crew and 272 passengers on board, was engaged on a scheduled service from London Heathrow to San Francisco. Engine start and the taxi out to the holding point for Runway 27L were normal.

The aircraft was cleared for take off at 14:32 hours, and became airborne one minute later, at 14:33 hours. At 14:34 hours, the Heathrow tower controller instructed the crew to change to the London Control frequency of 119.775 MHz. The commander, who was the pilot flying (PF), reported that the first sign of a malfunction was shortly after rotate when smoke was seen to emanate from the air vents on the flight deck.

The commander instructed the crew to don their oxygen masks and continued to fly the aircraft manually. The crew did not don their smoke goggles for although smoke was present their view of the instruments was not impeded. A few moments later the cabin attendants in both the 'first class' and 'coach class' cabins contacted the flight deck advising that their cabins were also filling with smoke. There were no associated messages on the electronic indication and crew alerting system (EICAS).

At 1,500 feet the auto throttle reduced engine thrust to climb power and at the same time the crew heard a 'bang' from the left engine and noticed that the left engine N1 and oil quantity had reduced to zero. When the crew checked in on the London Radar frequency they transmitted 'OKAY WE'VE GOT SMOKE IN THE COCKPIT WE'RE GONNA NEED TO COME BACK AROUND FOR A LAND BACK AT HEATHROW'.

The controller's response was '...SORRY SAY AGAIN'. The crew repeated their transmission by saying 'DECLARING AN EMERGENCY WE'RE GONNA NEED TO COME BACK TO LONDON HEATHROW'. The radar controller acknowledged this transmission and cleared the aircraft to climb to 6,000 feet.

The crew however stated that they wished to maintain 2,000 feet and that they were already in a turn onto a downwind heading. The controller cleared the aircraft to turn onto a heading of 090 degrees. By now the landing gear and flaps had been retracted and fuel dumping had been initiated. At or about this time the crew also carried out the emergency drills for 'Smoke in the Cockpit' followed by 'Engine Severe Damage/Separation'.

Air Traffic Control then asked the crew '...CAN YOU TELL ME WHAT THE PROBLEM IS'. The crew replied 'WE'VE
GOT AN ENGINE FIRE'. At 14:35:30 hours, they were transferred to the London Area and Terminal Control frequency of 120.400 MHz. After initial contact ATC advised the crew that they were downwind for Runway 27R.

The crew replied 'OKAY WE'RE VECTORS FOR 27 RIGHT WE'VE GOT AN ENGINE FAILURE SIR NEED TO GET BACK ON'. Moments later ATC advised the crew of the ILS frequency for Runway 27R and asked them if they were able to make an ILS approach. The crew did not reply but repeated the ILS frequency when it was transmitted again by ATC. They were then asked how many track miles they needed from their position which was 5 nautical miles south of Heathrow.

Their reply was to be positioned on finals at 10 nautical miles. The crew then asked to climb to 3,000 feet. At 14:37:30 hours, ATC transmitted that Runway 27L was available, gave the crew the ILS frequency, and stated that 27L would now be their landing runway. With 12 track miles to run ATC asked the crew if they intended to evacuate the passengers on landing.


The aircraft established on the centre line for Runway 27L at 9 nautical miles from touchdown. At 14:41:30 hours
the crew called 'HEATHROW IN SIGHT'. ATC cleared the aircraft to land on either 27L or 27R at the crew's discretion.

At 3.5 nautical miles from touchdown the crew were transferred to the Heathrow Tower frequency. The aircraft landed uneventfully at 14:43:30 hours, 85,000 lb above its maximum normal landing weight, having jettisoned approximately 25,000 lb of fuel.

Fire vehicles pre-positioned for the emergency followed the aircraft after landing. As the aircraft vacated the runway, the crew asked ATC if the fire crews could see anything. ATC advised the crew to contact the fire crews directly on frequency 121.6 MHZ. The fire crews advised the tower that all was well and followed the aircraft to stand where the passengers disembarked normally.

At no point was there an Engine Fire indication on the flight deck and thus the flight crew did not discharge any fire bottle into the engine."

Accident investigation:
Investigating agency: AAIB
Report number: DCA98WA074
Status: Investigation completed
Download report: Final report


1. AAIB:
2. FAA:


United Airlines Boeing 777-200 N796UA at Seattle-Tacoma International Airport 11-3-2012 N796UA (6833086234)

Revision history:

27-Jun-2016 13:49 Dr.John Smith Added
27-Jun-2016 13:51 Dr.John Smith Updated [Narrative]

Corrections or additions? ... Edit this accident description

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