Planning could hold key to disappearance of Flight MH370
A man stands in front of a board with messages of hope and support for the passengers of the missing Malaysia Airlines MH370 at the departure hall of the Kuala Lumpur International
By Siva Govindasamy and Tim Hepher
KUALA LUMPUR (Reuters) - Whether by accident or design, whoever reached across the dimly lit cockpit of a Malaysia Airlines jet and clicked off a transponder to make Flight MH370 vanish from controllers' radars flew into a navigational and technical black hole.
By choosing one place and time to vanish into radar darkness with 238 others on board, the person - presumed to be a pilot or a passenger with advanced knowledge - may have acted only after meticulous planning, according to aviation experts.
Understanding the sequence that led to the unprecedented plane hunt widening across two vast tracts of territory north and south of the Equator is key to grasping the motives of what Malaysian authorities suspect was hijacking or sabotage.
By signing off from Malaysian airspace at 1.19 a.m. on March 8 with a casual "all right, good night," rather than the crisp radio drill advocated in pilot training, a person now believed to be the co-pilot gave no hint of anything unusual.
Two minutes later, at 1.21 a.m. local time, the transponder - a device identifying jets to ground controllers - was turned off in a move that experts say could reveal a careful sequence.
"Every action taken by the person who was piloting the aircraft appears to be a deliberate one. It is almost like a pilot's checklist," said one senior captain from an Asian carrier with experience of jets including the Boeing 777.
There is so far no indication whether the co-pilot was at fault or had anything to do with turning off the transponder. Pilots say the usual industry convention is that the pilot not directly responsible for flying the plane talks on the radio.
Police have searched the premises of both the captain and co-pilot and are checking the backgrounds of all passengers.
Whoever turned the transponder to "off", whether or not the move was deliberate, did so at a vulnerable point between two airspace sectors when Malaysian and Vietnamese controllers could easily assume the airplane was each others' responsibility.
"The predictable effect was to delay the raising of the alarm by either party," David Learmount, operations and safety editor at Flight International, wrote in an industry blog.
That mirrors delays in noticing something was wrong when an Air France jet disappeared over the Atlantic in 2009 with 228 people on board, a gap blamed on confusion between controllers.
Yet whereas the Rio-Paris disaster was later traced to pilot error, the suspected kidnapping of MH370's passengers and crew was carried out with either skill or bizarre coincidences.
Whether or not pilots knew it, the jet was just then in a technically obscure sweet spot, according to a top radar expert.
Air traffic controllers use secondary radar which works by talking to the transponder. Some air traffic control systems also blend in some primary radar, which uses a simple echo.
But primary radar signals fade faster than secondary ones, meaning even a residual blip would have vanished for controllers and even military radar may have found it difficult to identify the 777 from other ghostly blips, said radar expert Hans Weber.
"Turning off the transponder indicates this person was highly trained," said Weber, of consultancy TECOP International.