Missing Malaysian Flight 370: Selecting a Search Area
On June 26, 2014, the Australian Transport Safety Bureau (ATSB) released MH370 – Definition of Underwater Search Areas. Because an official explanation of what happened to Flight 370 has not been released, the ATSB needed a different way to prioritize areas for the underwater search. ATSB looked at how past airline crashes occurred and identified characteristic crew behaviors and flight paths. The “hypoxic crew” theory was declared the “best fit” for Flight 370’s course to the south.
Glide events, in-flight upsets, and hypoxic crew events emerged as the three most probable types of accident. Glide events were characterized by normal communication with the crew, normal plane maneuvers, and a pilot controlled glide after loss of engines. In-flight upsets were characterized by normal flight maneuvers with normal communications up to sudden loss of pilot control. Hypoxic events were characterized by long periods with no maneuvering of the plane and no communication, a steady altitude, and no pilot intervention. Flight 370 most resembled the hypoxic crew event. By comparing Flight 370 with different event characteristics, ATSB was able to limit an impossibly large search area to an area which can be searched.
FAA airworthiness directives for Boeing 777-200 series airplanes (the 777-200 and 777-200ER are almost identical planes; the 200ER is strengthened in certain areas to handle more weight and longer flight-times) may shed light on how this crew became hypoxic. For example, scribe lines for joints can become fatigue cracks. The cracks can lead to decompression of the airplane if allowed to expand. Also, latch pin bolts which secure the cargo door can fracture or fall out and lead to decompression of the airplane. New airworthiness directives are continually published as weaknesses are discovered, and any number of weaknesses could have caused a decompression event on Flight 370.