Flight International online news 09:00 GMT: Problems with the pressurisation system appear almost certainly to be behind the fatal loss yesterday of a Helios Airways Boeing 737-300 in Greece, but the possible sequence of events remains a puzzle.

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Two Greek air force F-16s inspected the aircraft from the air after air traffic control lost communication with it while it was en route from Larnaca, Cyprus to Athens.

A Greek Government spokesman says the fighter pilots, intercepting at 34,000ft, saw only the first officer in the cockpit and he was apparently unconscious.

As for the captain's condition, the only piece of information came from a text message purported to have been sent by a passenger.

However, police now believe the text message, containing the words: “The pilot has turned blue. Cousin farewell. We’re freezing,” to be a hoax.

Police in Greece now think the man who said he received the text message was lying because the name of the man he claimed sent the message did not appear on the list of official victims.

Greek rescue services say that passengers’ bodies recovered from the wreckage, in hills some 20nm north of Athens, were wearing oxygen masks.

There are unconfirmed reports that the crew reported a problem with the on-board air circulation systems at an earlier stage in the flight.

And Flight International’s sister publication Air Transport Intelligence reports that Turkish air traffic controllers observed the aircraft transmitting the 7700 international emergency code from its transponder.

A Greek government official yesterday told CNN that the fighter pilots later observed people in the cockpit before the aircraft crashed.

The circumstances of the final crash into the ground, at 12:20, are not known.

Numerous pilots who have commented on the accident confess to being perplexed over the possible on-board sequence.

The fact that the passengers’ oxygen masks deployed – an automatic process – appears to imply that the pilots should have received aural and visual warnings that there was a problem with the cabin altitude.

The pilots’ drill would call for them to don immediately their own oxygen equipment – which is entirely separate from the cabin system – before attempting to diagnose the problem and descending to around 10,000ft where the air would be breathable again.

The absence of the captain from the cockpit, has led to speculation that the captain entered the cabin to investigate what was happening and then lost consciousness. If the first officer had not put on his own mask then he too would have fallen unconscious.

But it remains unclear what fault or faults would have caused the lack of pressurisation in the first place. The fighter pilots are not reported to have mentioned any physical damage to the aircraft that would cause a loss of cabin air.

Separately, Athens chief coroner Phillippos Koutsaftis told a press conference that at least six of the 121 victims of the accident were alive at the time of the impact - although not necessarily conscious.


Source: Flight International