Incident
During taxi for departure, a Boeing 767 was observed by another aircraft crew to have smoke and flames emanating from its auxiliary power unit (APU) exhaust. In response, the crew of the Boeing 767 shut down the APU and began coordinating with dispatch to return to the gate.
Evacuation
The tower subsequently directed the crew to hold their position and shut down the engines. Shortly after, the tower advised that the Fire Marshall had called for evacuation of the aircraft due to continued smoke from the APU exhaust. The aircraft was evacuated using the evacuation slides at the door exits. During the evacuation, one passenger sustained serious injuries.
Inspection and Resolution
Inspection of the APU revealed that the fuel control unit and the gearbox shutoff valve required replacement. After these components were replaced, the APU was test-run with no further discrepancies noted.