The Boeing 767's penultimate journey began when it left Cairo for New York on Friday.

As it approached the US coast, air traffic controllers told the crew to divert from JFK airport to Newark airport, New Jersey, due to poor weather.

The plane landed without incident at 0802 Eastern Daylight Time and, at 1151 EDT, departed for Los Angeles.

Flight 990 landed at LAX airport at around 1409 EDT where all the passengers and crew left the plane.

The change-over team prepared the aircraft for the return journey, replenishing its stocks of food, pillows and blankets.

Ahmed el-Habashy, Captain of the Egyptair Flight 990

Los Angeles airport authorities have reported that during refuelling there was only one mechanical incident of note - the changing of a tyre.

The plane, now around four hours behind schedule, departed for the return leg to New York at around 1653 EDT with 33 passengers on board.

The five-hour eastbound flight was reported to be uneventful and Flight 990 landed safely at JFK airport, again without incident, at around 1am on Sunday, just before clocks went back an hour to Eastern Standard Time.

The only passenger to leave the plane in New York was Ed McLaughlin - a bereavement counsellor and consultant to EgyptAir.

The refuelling and reloading took just over an hour and at 0103 EST the airliner, now carrying 187 passengers and 18 crew, three off duty, taxied from its gate to the runway.

JFK control: No unusual reports

After a brief wait for clearance, Flight 990 departed JFK at 0119 EST.

Robert Kelly, aviation director for the New York Port Authority said on Sunday: "There were no delays, no disruptions, no events that were untoward in any way."

The flight plan would take the airliner on a standard route used for transatlantic crossings.

From Nantucket Island, the flight would have turned north towards Nova Scotia and Newfoundland, following a Great Circle over the north Atlantic towards Europe and Africa.

Minutes after take-off, air traffic controllers at JFK cleared the pilots to take the airliner to the standard cruising height of 33,000ft and at 0147 EDT the crew carried out a standard radio contact to JFK's satisfaction. Nothing was out of the ordinary.

Three minutes later, JFK controllers saw the airliner plummeting on their radar screens.

The provisional estimate of the descent suggests that the airliner lost 14,000ft in 30 seconds before finally hitting the ocean around 60 miles south/south-east of Nantucket Island some 90 seconds later.