Event Description
While the aircraft was being pushed back from the gate, the crew initiated the start sequence for the #4 engine. During this process, the auxiliary power unit (APU), which supplies electrical power to the engine starter, tripped off the line. The loss of electrical power to the starter prevented the engine from being motored, leading to a hung start at approximately 25% N2 (fan speed). As a result, pooled fuel continued to burn within the engine compartment.
Crew Response
The crew was alerted to the fire condition and promptly discharged the #4 engine fire extinguisher. They also ordered an immediate evacuation of the aircraft.
Outcome
Shortly after the commencement of the evacuation, the fire terminated. No further information is available regarding the extent of damage or any injuries.