TORONTO – It’s the sixth day of the international search for missing Malaysia Airlines flight MH370—a plane that’s got more than 20 search vessels looking for it and as many conspiracy theories surrounding its disappearance.
Malaysian authorities, after initially denying a U.S. report, expanded their search Thursday after admitting the plane may have flown for several hours after its last contact with the ground.
We know there was no distress signal sent and that the plane’s transponders (which identify aircraft to radar systems and other planes by broadcasting its location) weren’t working. Experts say a massive electrical failure is one possibility, but the pilot or an informed passenger could’ve also switched them off in hopes of an undetected trip. When it emerged that two Iranian men boarded the plane with stolen passports, terrorism was also put forth as a possibility—though stolen passports don’t often mean hijacking, and in this case that was largely ruled out.
Past searches have shown that finding aircraft wreckage can take weeks or longer, but here are some of the theories put forward by experts, aviation chat rooms and the public so far.
Ryerson University associate professor in aerospace engineering David Greatrix said pilot disorientation is possible with “night-time flight at play” and if instrument flight data display went awry or the flight crew became distracted.
Former U.S. Airways pilot and CEO of Safety Operating Systems Capt. John M. Cox said Saturday the pilots may have taken the plane off autopilot and not realized if it went off course (for another five or six hours from last point of contact) until it was too late. This is unlikely given the plane would probably have been picked up by radar elsewhere.
Hypoxia is one of the theories presented in a Britain-based chat room with contributors identifying themselves as pilots and flight staff. It’s the sudden depressurization and resulting lack of oxygen that would leave a crew and passengers unconscious.
Another example of hypoxia was a Learjet carrying pro-golfer Payne Stewart and five others, which crashed in South Dakota in 1999 after flying for several hours on autopilot before running out of fuel. Reports cited investigators saying the plane lost cabin pressure and all on board died after losing consciousness for lack of oxygen.
Greatrix said the cause of the cabin pressure dropping in the 1999 incident was “not definitively identified in the follow-on investigation, but the maintenance records for that plane had identified fuselage sealing problems being looked at.”
“Whether a gradual or rapid depressurization might have occurred, one would surmise that the likelihood of a larger aircraft like the 777 being affected such as that all aboard would become unconscious seems substantially less likely than a smaller aircraft like the Learjet,” Greatrix said.
Greatrix said bombs are a possibility, as they “have been placed on aircraft for a variety of reasons in the past; not necessarily a terrorist act.”
“Security procedures in that region of the world would be assumed to be reasonably effective, but the false passport issue raises flags,” he wrote in an email to Global News.
Pan Am Flight 103 between London and New York in December 1988, as well as an Air India flight in June 1985 between Montreal and London were brought down by bombs, and a plane in September 1989 flown by French airline Union des Transports Aeriens blew up over the Sahara Desert.
Failure of the airframe or an engine
Greatrix said airframe structural failure, perhaps due to a “conventional” cause “like fatigue causing rupture of a critical component” was possible, but less likely since the Boeing 777 in question was a younger airplane with a good track record.
“Structural failure due to a less conventional cause, say accidental/electrical fire/smoke breakout, possible but low likelihood,” he added.
Failure of both engines
Greatrix believes it’s more likely (but still rare) that one engine would fail versus both.
In January 2008, a British Airways 777 crashed about 1,000 feet short of the runway at London’s Heathrow Airport because the engines lost thrust due to ice buildup in the fuel system.
Such a scenario is possible, but the typical 20-minutes of gliding should give pilots plenty of time to make an emergency call.
When a US Airways A320 lost both of its engines in January 2009 after taking off from LaGuardia Airport in New York, it was at a much lower elevation and Capt. Chesley B. “Sully” Sullenberger still had plenty of communications with air traffic controllers before ending the six-minute flight in the Hudson River.
While all indications show there were clear skies, Greatrix said high-altitude turbulence, hail or a lightning strike are possible, but with a “very low probability of leading to crash” at the cruise altitude of more than 35, 000 feet.
An Air France flight from Rio de Janeiro to Paris crashed during a bad storm over the Atlantic Ocean in June 2009. The airspeed indicators gave false readings, bad decisions were made by the pilots, and this led the plane into a stall, causing it to plummet into the sea. The pilots never radioed for help, and all 228 passengers and crew died.
Greatrix said after six days, it’s unlikely hijackers are holding passengers at an undisclosed location. Other experts agree a traditional hijacking seems unlikely since the captors typically land at an airport and have some type of demand.
“Hijacking leading to destruction of the aircraft, as in the 9/11 Pennsylvania crash or related scenario, less unlikely,” he wrote.
While Greatrix believed this to be unlikely, there were two large jet crashes in the late 1990s that investigators suspected were caused by pilots deliberately crashing the planes.
Secret U.S. strike or accidental shoot-down
Greatrix said there was no chance of a secret U.S. carrier strike, but in July 1988, the United States Navy missile cruiser USS Vincennes (above) accidentally shot down an Iran Air flight, killing all 290 passengers and crew. In September 1983, a Korean Air Lines flight was shot down by a Russian fighter jet.
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“No comment, considering the lives that have likely been lost,” he wrote.
With files from The Associated Press