My friends are emailing me with the latest theories about Malaysia Airlines 370. There are many articles and blog postings (example) that posit that an electrical fire on board the airplane caused the crew to try to divert to a nearby airport. The original posting from Chris Goodfellow suggests the following:
- an electrical fire caused smoke in the cockpit
- the pilots pulled lots of breakers
- the breakers that they pulled disabled everything that sends signals out of the airplane, e.g., the transponders and the ACARS
- the breakers that they pulled had no effect on the air data computers, attitude reference systems, or autopilots, thus enabling the plane to continue to fly on autopilot for 6 more hours
- the pilots tried to divert to a nearby airport
This does not match up very well with another bit of information we have about Flight 370, i.e., that the airplane was diverted (via the FMS (like the GPS in your car)) to an IFR intersection, which is an arbitrary point defined by a five-character code. If the pilots wanted to go to an airport they would presumably have typed in the four-letter airport ID instead of a five-letter IFR intersection in the middle of nowhere. (e.g., one could go to BOSOX with an airplane GPS and land on top of an exurban dentist’s McMansion and SUV collection or one could go to KBOS and find an assortment of two-mile-long runways; which would you prefer?).
The other problem is that autopilots just love to disconnect (I wrote about this in my first conjecture on Air France 447). So if one were to pull breakers at random one would be much more likely to cause autopilot disconnection (and a crash much sooner than 6 hours later unless the plane was being hand-flown) than to cause transponder and ACARS disconnection.
Finally you have to remember that, unlike in a crummy four-seat plane, all of that fancy stuff in front of the pilots in an airliner is not the real stuff that runs the airplane. It is mostly switches, knobs, and displays that connect through wires to the actual stuff, which is typically in “electronics bays” underneath the passenger seats (photos; don’t spill your Diet Coke if you want to get to Denver!). So even if a fire burned up the cockpit the transponders would continue to operate because the thing on the dashboard that says “transponder” is in fact just a control panel for a transponder located elsewhere. (I answered the question of Why is it possible to turn off the transponder? in a comment on an earlier posting.)
So I’m still as confused as anyone about what happened to this beautiful B777 and the passengers but based on the other information that we’ve received (many hours of pings, turn to an IFR waypoint, etc.) I am pretty sure that there was not an electrical fire on board that yet left the autopilot and associated systems untouched.