One of the early theories about the disappearance of Malaysian Airlines Flight MH370 has been the prospect of a fire in the electronics bay, or elsewhere in the airplane, that led pilots to begin pulling circuit breakers to isolate the fire. This theory continues that the transponders and radio communications, including ACARS, systematically failed as a result of the fire.
This scenario, while it can’t be totally ruled out, is unlikely, in our view.
The best example of this scenario is Swissair Flight 111, a McDonnell Douglas MD-11, that crashed off Nova Scotia in 1998. Shortly after takeoff from New York for Geneva, Switzerland, the pilots smelled smoke and smoke eventually began to emerge in the cockpit. However, the pilots radioed Air Traffic Control of the situation and began to divert to Halifax. It is true they began to pull circuit breakers, per procedure, to isolate the problem. However, even as it got worse, the pilots radioed updates and the decision to dump fuel prior to an emergency landing. Thus, this fire scenario hypothesized for MH370 breaks down. Tragically, Swissair 111 crashed as the fire went out of control. This is an important point that will be addressed below.
Associated with the theory that a fire somehow led to hypoxia is another of which we’re skeptical. This would require a hull breach and the failure warning equipment to alert the crew.
Another theory that surfaced last week is the presence of lithium-ion batteries in the cargo manifest. At least one or two plane crashes occurred because lithium-ion batteries in cargo caught fire and went out of control. These are the UPS Boeing 747F crash in Dubai and the Asiana Airlines 747 crash in the Pacific. However, in both cases, the pilots radioed that a fire existed. As we know, there was no communication from MH370.
Another reason a fire is unlikely on MH370 is this: according to an Airbus study in 2012, it takes just eight minutes for a fire to go out of control and the airplane has to be on the ground within 15 minutes, with the implication being that the airplane would be lost beyond this time. We know from the satellite pings that MH370 was airborne for up to seven hours after contact was lost. If any fire occurred strong enough to cause the loss of all radios and transponders, it certainly would have resulted in the loss of the airplane well before seven hours.
Furthermore, any pilot knows that with a fire, you land at the nearest available airport. Additionally, flipping the transponder to 7700 is a mere flick of the wrist and alerting potential air traffic in the vicinity (so, among other things, you don’t collide with it) is also important.
The theory that a fire overcame the crew and passengers and the airplane flew on for hours on auto pilot or in a computerized stable state also seems unlikely. The fire would essentially had to have snuffed itself out to avoid destroying the airplane.
Finally, there is the airplane itself. We have consulted two 777 pilots, both of whom believe that a fire or electrical failure of such magnitude as to take out all five radios, two transponders and the ACARS system simultaneously is extremely unlikely.
“There is a big effort [by Boeing] to do separation of the electronics,” one of the pilots tells us. “It’s unlikely a fire would take them down.”
As for pilots being overcome by smoke, one of the 777 pilots we talked with points out that first, the pilots have a full-face smoke mask to protect them from smoke and second, “the airplane [design] does a god job of keeping smoke out of the cockpit.”
Finally, all cargo compartments and the electronics bay have smoke and fire detection systems that would provide ample warning to the pilots of something amiss–which in turn would allow the pilots time to radio Air Traffic Control.
For these reasons, we do not believe there was a fire on board.
Debunking the 45,000 ft hypoxia theory
An early area of speculation evolved around the report that MH370 had gone as high as 45,000 ft and descended to as low as some 25,000 ft. Theorists suggested this high-altitude report was to depressurize the cabin and kill all the passengers, cabin crew (and potentially the legitimate pilots), enabling the Bad Guys (whoever they might be) to steal the airplane without having more than 200 people to contend with.
Both of our 777 pilots we consulted pointed out the obvious: you don’t have to go to 45,000 ft, which is nearly 2,000 ft above the certificated service ceiling of the 777, to suffocate the people on board. This can be done at 25,000 ft.
Furthermore, 45,000 ft is probably achievable only with a “light” airplane (i.e., one where most fuel has been burned off). MH370 was less than an hour into a six hour flight (plus reserves) and probably wasn’t light enough (though our pilots did say actual calculations with the known payload and fuel on board would have to be undertaken to be sure).
Finally, 45,000 ft would be flirting with the “coffin corner,” the flight envelope in which engines and aerodynamics would be hard-pressed to remain stable. Any slip and the airplane could suffer a high altitude upset.
Such an upset could explain why the airplane descended from this reported 45,000 ft to 25,000 ft until the aircraft was recovered–but this suggests a pilot with a skill level.
Perhaps a more plausible theory–if the altitude reports are accurate–is a fight in the cockpit, according to our pilots, that caused the airplane to go out of control.