One of the pilots of the missing Malaysia Airlines flight liked to entertain female passengers in the cockpit, it emerged yesterday (Tuesday), as a new theory suggested a fault with the plane could have rendered the crew unconscious.
The airline said it was "shocked" by pictures of First Officer Fariq Abdul Hamid posing with two South Africans who said he smoked on the flight deck and allowed them to stay during take-off and landing, against airline rules. The mystery surrounding the fate of Flight MH370 deepened after military sources said it may have flown 350 miles after it last transmitted its location.
Four days after the Boeing 777 disappeared on its journey from Kuala Lumpur in Malaysia to Beijing, with 239 passengers and crew, the search area was extended. Radar readings suggested the plane had turned and flown west with its transponder and other tracking systems switched off.
US transport officials warned four months ago of a weak spot in Boeing 777s that could lead to rapid decompression and even to the aircraft breaking up in mid-air.
One possibility is that such a fault rendered the crew unconscious, leaving the aircraft to fly on before crashing into the sea.
Meanwhile, Malaysia Airlines said it was "taking very seriously" an account from Jonti Roos, a former passenger who said that Mr Hamid invited her and a friend on to the flight deck of another Malaysia Airlines aircraft, flying from Phuket, Thailand, to Kuala Lumpur in 2011.
She said that he had spent much of the journey smoking and chatting to his guests.
Miss Roos said that she and Jaan Maree were picked out of the boarding queue to join the pilots for the one-hour flight, and sat in jump seats in the cockpit during take-off and landing.
She told Channel 9 television in Australia: "Throughout the whole flight they were talking to us, they were actually smoking throughout the flight, which I don't think they're allowed to be doing and they were taking photos with us in the cockpit while they were flying the plane."
She claimed that for much of the trip the pilots were not even facing the front of the plane.
Miss Roos said that while the pilots were "possibly a little bit sleazy" and invited the women to stay with them in Kuala Lumpur, she felt they were in control of the aircraft. After MH370 disappeared on Saturday, the authorities said it was lost about an hour after it took off from Kuala Lumpur.
But a senior military officer who has been briefed on the investigation said: "It changed course after Kota Bharu and took a lower altitude. It made it into the Malacca Strait."
Until now an enormous search operation has focused on ground controllers' last point of contact with the jet: a stretch of the Gulf of Thailand between Malaysia and Vietnam.
However, aircraft with sensors so sensitive they can spot objects as small as basketballs have failed to find any trace of MH370.
Now the focus has switched to the other side of the country following the reports that the aircraft had been detected at 30,000ft above the strait, one of the world's busiest shipping channels. That would mean that the aircraft had flown back over Malaysia and into the seas beyond.
It emerged yesterday that the Federal Aviation Administration in Washington drew up an airworthiness directive relating to Boeing 777s in November. It was prompted by reports of cracking in the fuselage skin under the aircraft's satellite antennae.
The FAA, which supervises the safety of American-made aircraft such as Boeings, told airlines to look out for corrosion under the fuselage skin. This, the FAA said, could lead to rapid decompression as well as the plane breaking up.
During a maintenance inspection, one 777 was found to have a 16in crack under its antenna. The report said: "Cracking and corrosion in the fuselage skin, if not corrected, could lead to rapid decompression and loss of structural integrity of the aeroplane."
According to a Malaysian Airlines spokesman the missing aircraft was serviced on February 23, with further maintenance scheduled for June 19. Despite both the Boeing 777 and Malaysia Airlines having good safety records, there have been other incidents which could prove relevant during the investigation of the crash.
In 2005 a 777 operated by the airline suffered problems with its autopilot on a flight between Perth and Kuala Lumpur. It led to the plain pitching up into a sudden 3,000ft climb, almost causing the plane to stall.
The problem led to another airworthiness directive to correct a fault that had been found on 500 Boeing 777s. Airworthiness directives are commonplace, similar to car recalls.
In the majority of cases airlines are told to watch out for and correct the fault during the plane's routine maintenance schedule.
While investigators from Malaysia and the National Transportation Safety Board in Washington search for the plane's black box, they will also be able to glean vital information from a live data stream broadcast during the flight.
Known as aircraft communications addressing and reporting system, it is the equivalent of an "online black box".
While air accident investigators were looking into possible mechanical failure, police said their own investigation was "focusing on four areas: hijacking, sabotage, psychological problems of the passengers and crew and personal problems among the passengers and crew".
They could not rule out the possibility that a pilot might have crashed deliberately.
While there is no indication that either Captain Zaharie Ahmad Shah or Mr Hamid would have done so, such incidents are not unheard of. In 1999, the pilot of an EgyptAir flight, Gameel Al-Batouti, crashed a Boeing 767 carrying 217 people into the Atlantic while chanting "I rely on God", according to an investigation by US officials. His precise motives remain a mystery.