[wyuenho]

The aircraft would also have had to fly through Cambodian, Laotian and Vietnamese airspaces, twice in Vietnamese's case, before getting into Chinese airspace.

I'm also not sure inertial guidance will direct the aircraft off course enough to sink in the East China Sea.

This article also doesn't explain why a Vietnamese military radar had detected it to be U-turning just before it had to enter its airspace. This article is bunk.

[will_asouka]

Yes, inertial is good for worst case 5nm accuracy for 5 hours after an update from GNSS or ground based nav aids.