CNN Anderson Cooper 360 November 3, 2015 01:09:00
The number of flashes are the key. if there was a muffle launch youd get an infrared flash for the launch itself and a second flash, a second infrared signature for the impact itself, and possibly even a third when the structure struck the floor of the desert as further fuel might have exploded, so the number of heat signatures is crucial. if in fact only one was detected, that in some respects might steer one away from a missile launch and on to some idea of an explosion on board the aircraft. ...
Second Flash Muffle Launch Second Infrared Signature Missile Launch Heat Signatures Surface To Air Missile
Source: archive.org