SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 777 airplanes. This proposed AD was prompted by a report of cracking in the fuselage skin underneath the satellite communication (SATCOM) antenna adapter. This proposed AD would require repetitive inspections of the visible fuselage skin and doubler if installed, for cracking, corrosion, and any indication of contact of a certain fastener to a bonding jumper, and repair if necessary. We are proposing this AD to detect and correct cracking and corrosion in the fuselage skin, which could lead to rapid decompression and loss of structural integrity of the airplane.





Update 3/12, 16:43:

[Here was an earlier anonymous tip I received saying that the AD did not apply to MH370].

Update 3/13 0:00:

I got an email from a reporter suggesting that the AD did, in fact apply to MH370.

Update 3/13 2:36: Latest statement, straight from a Boeing spokesperson: The antenna covered by the pending AD was not installed on MH370, so that airplane is not subject to the AD or the related Service Bulletin. So, it has been determined that the AD was not relevant to this plane. However, it served as the key inspiration for an alternative explanation.

New Summary:

There’s a chance that MH370 flew for hours on autopilot after we lost radar contact with it. The idea is that some kind of decompression event incapacitated the passengers and crew, while also somehow disabling Satellite and Radar communication systems.

If such a decompression were caused by a rupture in the skin of the fuselage, there’s a chance satellite and/or radar antennas would have suffered direct physical damage from the blowout.

Original Summary:

When I first wrote this, it seemed likely that a fuselage section near the SATCOM antenna adapter failed , disabling satellite based - GPS, ACARS, and ADS-B/C - communications, and leading to a slow decompression that left all occupants unconscious. If such decompression left the aircraft intact, then the autopilot would have flown the planned route or otherwise maintained its heading/altitude until fuel exhaustion.

A slow decompression (e.g. from a golfball-sized hole) would have gradually impaired and confused the pilots before cabin altitude (pressure) warnings sounded. There’s also the possibility of an extremely-rapid decompression, and it’s described toward the end of this post.