My experience was with air traffic control rather than design and mechanics.
I donno......
But why in the world would there be a cover-up?
If it is proved to be a terrorist act it will just further inflame Americans and make it easier for the Administration to pursue its goal of killing OBN et al.
I cannot explain this inconsistency: The FBI is known to be investigating the otherwise unremarkable disappearance of a Harvard biologist, and they are swabbing down every inch of a 94 year old woman's house, the hair salon she went to, etc. while there is no criminal invetisgation in an airplane crash that happened almost within sight of the WTC ruins when Bush was standing right there, there was a specific threat of more plane disasters, and a probable saboteur had been caught in a shipping container on his way to Canada with fake airline maintenence IDs. Nope, can't be terrorism!
"Coverup" is too strong a word. It implies some kind of criminal intent. I think the downplaying of terrorism in this case is just part of general propoganda and ass-covering. Who would want to admit they could still reach out and touch us that way? Why risk an unpredictable public reaction? So those of us who fly a lot are left to our own to figure out what probably happened.