Europe South Asia Asia Pacific Americas Middle East Africa BBC Homepage World Service Education



Front Page

World

UK

UK Politics

Business

Sci/Tech

Health

Education

Sport

Entertainment

Talking Point

In Depth

On Air

Archive
Feedback
Low Graphics
Help

Thursday, November 18, 1999 Published at 10:05 GMT


World: Americas

Flight 990: What happened and when?



It was all over in two minutes and 40 seconds.

The loss of flight 990
EgyptAir Flight 990 investigators are currently relying on three sources for evidence of what happened: Radar reports of the aircraft's flight in the last minutes and the airliner's two "black box" recorders - one for flight data and the other for the voices in the cockpit.


[ image:  ]

Some 40 minutes into the transatlantic flight and everything appeared normal.

Jim Hall, head of the US's National Transportation Safety Board, charged by the Egyptian government with carrying out the investigation, said: "The data show an uneventful flight, cruising in level flight at 33,000 feet.

By this point, the aircraft has reached its standard transatlantic altitude and the crew had activated the autopilot system for navigation across to Europe and North Africa.


[ image:  ]

According to the flight data recorder (FDR), the autopilot disconnected less than a minute later. While this is an unusual procedure, an autopilot can be easily overridden by a pilot at any moment if the crew wants to take control of the aircraft.

Ten seconds later, both radar returns and data from the FDR reveal that the engines appeared to throttle down and there was an overall reduction in the amount of thrust.

By 01:50 the plane had started its descent.


[ image:  ]

Flight 990's passengers experience complete weightlessness as the dive becomes steeper.

The airliner accelerates to around 0.86 the speed of sound.

The aircraft's master warning system activates and the engine monitors warn of low oil pressure. Records appear to show that the crew ignored the warnings.


[ image:  ]

It takes the aircraft less than 20 seconds to dive 12,000ft. Seconds later, as the aircraft descends below 20,000ft, the start levers on both engines switch from run to cut-off, shutting down the engines.

Boeing has said that the engines could only have been intentionally shut down.

At about 1:50.30, the aircraft appears to pull out of its nose dive.


[ image:  ]

Radar traces show that the aircraft then began to stabilise and gain height, reaching some 24,000ft over the next minute.

However, considering that the aircraft had entered the steep dive at extremely high speed, most of the height could have been gained by the aircraft's forward momentum.

There is no evidence that the engines were throttled up.

Despite the radar images showing this gain in height, the aircraft reaches a peak, rather like a ball having been thrown in the air, and re-enters a steep and final dive to the sea.

Jigsaw puzzle

Air accident experts are continuing to extract information from the flight data recorder and may even feed it into a Boeing cockpit simulator to try and re-enact the final moments in the cockpit.

But the most crucial job they have at the moment is synchronising the cockpit voice recordings with the FDR material.

The NTSB is continuing translation work, aided by Arabic speakers with knowledge of Egyptian idiom, but already there are several significant pieces of the jigsaw which have to be matched to events.

NTSB officials have yet to explain the sequence or timing of events on the voice recorder but they have released some of the key features to the media.

Investigators say that the opening and closing of a cockpit door can be heard, following by a voice believed to be reciting the Shahada, the Islamic affirmation of faith.

Another voice, believed to be that of the pilot is then heard saying; "What's going on", before being heard again saying: "Pull with me, pull with me".



Advanced options | Search tips




Back to top | BBC News Home | BBC Homepage | ©




Africa | Americas | Asia-Pacific | Europe | Middle East | South Asia



Relevant Stories

03 Nov 99 | Sci/Tech
Black box: Key to disaster investigations

02 Nov 99 | Americas
Experts debunk flight rumours

01 Nov 99 | World
Flight 990: The final hours





Internet Links


EgyptAir

National Transportation Safety Board

Professional Pilot's Rumour Network

Boeing


The BBC is not responsible for the content of external internet sites.




In this section

From Business
Microsoft trial mediator appointed

Safety chief deplores crash speculation

From Entertainment
Taxman scoops a million

Violence greets Clinton visit

Bush outlines foreign policy

Boy held after US school shooting

Memorial for bonfire dead

Senate passes US budget

New constitution for Venezuela

North Korea expels US 'spy'

Hurricane Lenny abates

UN welcomes US paying dues

Chavez praises 'advanced' constitution

In pictures: Castro strikes out Chavez

WTO: arbitration in EU-Ecuador banana dispute

Colombian army chief says rebels defeated

Colombian president lambasts rebels