Tuesday, September 8, 1998 Published at 01:07 GMT 02:07 UK
Flight 111's black hole
Crucial information missing
The "black box" flight-data recorder, which investigators hoped would reveal vital information about the crash of Swissair Flight 111 last week, contains no information from the plane's final crucial minutes.
However, a signal from the plane's other "black box" - the cockpit-voice recorder - has been detected by a Canadian navy submarine.
But he said there was no data for at least the last six minutes before the plane crashed last Thursday into the Atlantic Ocean off Canada, killing all 229 people aboard.
Mr Gerden said the data recording stopped once the plane dipped below 3,000 metres.
He said there was a strong possibility that the plane lost electrical power at that stage.
Investigators previously released details of the final conversations between the pilot and the control tower, which show that the plane hit the sea six minutes after losing its course.
If retrieved intact, the voice recorder would reveal other noises in the cockpit besides the pilots' conversation with controllers.
The first that air traffic controllers heard of the problem was 16 minutes before the crash.
The pilot announced: "Swissair 111 is declaring pan pan pan - we have smoke in the cockpit."
"Pan pan pan" is the expression used when an emergency is less acute than a mayday signal, which indicates imminent disaster. But the situation rapidly deteriorated.
The pilot suggested landing at Boston, but was told Halifax was closer, so he began heading in that direction.
However, the plane was at an altitude of around 10,000 metres and needed to lose height.
Air traffic controllers also gave the pilot permission to dump at least 30 tons of fuel to land safely to help it land safely.
"We have to land immediately," the pilot said, the last words the controller heard from the plane.
Radar signals showed that the airliner began flying off course in a rapidly descending loop over the sea.
Six minutes later, it hit the water.