Date & Time: Jul 15, 1979 at 0600 LT
Type of aircraft:
Crew on board:
Pax on board:
The aircraft was loaded with two rubber cargo bladders, filled with 1600 Imp gallons of aviation gasoline. The aircraft was parked overnight, until at 05:40 the 2 crew members arrived to perform the pre-departure checks. A smell of Avgas fumes was detectable, but not stronger than on similar trips. The engines were started, and when the no. 1 engine reached idle rpm, the crew proceeded with after-start checks. When both alternators and the left generator were turned on, a violent explosion occurred in the cabin. The nose gear collapsed and the rear airstair was blown off. Both pilots managed to escape before a fierce fire consumed the aircraft.
The reason for the accumulation and ignition of the vapours could no longer be definitely determined because of the complete destruction of the aircraft. However, the fact that the explosion occurred during the after-start check as electrical equipment was being turned on suggests equipment in the underfloor electrical bay as a probable source of ignition. Although such equipment is designed to be flameproof, the aircraft had an extensive repair history during which this protection may have been lost.