The tinfoil says that it got zapped in a US naval artillery accident...
I've never heard that one before. But, I've heard that the high tech Government types believe the nose of the aircraft fell off, causing a zoom-climb of more than 3,000 feet making the people on the ground believe that the crashing 747 was a missile streaking skyward. Now, I can believe that one, can't you?
Some say it was Iran.