voice recorder sounded like a possible explosion. could that be possible? panam flight 103 was brought down by a bomb placed in the hug gauge hold. the bomb exploded as the jet was at 31,000 feet. the final moments captured on the cockpit voice recorder left little for investigators to work with. just 170 milliseconds. >> it's going to be loud enough to severely overload the input system to the cockpit voice recorder. >> reporter: in the final moment flight 103's voice recorder shows nothing on the pilot's mike and a recording of everything in the cockpit appears to capture a loud noise but investigators could never determine what it was. >> it is going to overload the microphone, the amplifier and recording system and cause