We’re still collecting data for this aircraft. Routes appear once we’ve seen it fly enough times.
The Board determines that the probable cause of this accident was the failure in the No. 4 engine of the exhaust valve of the No. 2 cylinder and the exhaust connection of the No. 1 cylinder which resulted in fire in flight. A contributing factor was the inadequacy of the seal between the firewall and nacelle skin and between individual cowl panels which permitted the fire eventually to reach Zone 3 and to become uncontrollable.
Douglas C-54