Date: 201210
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Weather elements / visibility: Rain
Light: Night
Aircraft: B757-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
ATC / advisory: Ramp ZZZ
Aircraft component: APU
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion; Training / Qualification
Second reporter function: First Officer; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Ground Personnel
When detected: Aircraft In Service At Gate
Result: Aircraft Equipment Problem Dissipated; General Maintenance Action; General Declared Emergency
Contributing factors: Aircraft; Human Factors; Procedure
Primary problem: Aircraft

Narrative: After landing; the APU failed three consecutive start attempts; and we parked at the gate and shut down one engine. The ground crew was gesturing wildly toward the airplane; and I kept giving the hand signal to plug in external power; thinking they were referring to the still-running engine. After a minute or so of this confusion; a ground crewmember plugged in a headset and told us that 'the tail of the airplane is on fire!' When asked to for more information he kept replying that there was a fire in the tail; or that the tail was on fire. This could have meant anything from some flame at the APU exhaust; up to the tail being completely engulfed in flames; and spreading. With the recently failed APU start attempts; and lack of more specific information; it was logical to conclude that there was a fire in the area of the APU. A call to the aft cabin interphone went unanswered. We pulled the APU fire handle and fired the extinguisher bottle; and began the evacuation checklist. The First Officer established radio contact with Ground Control to request emergency equipment; but they had already been called and arrived about that time. They reported no smoke or fire; and there was never any indication of an APU fire in the cockpit. At this point we terminated the evacuation checklist; established external power; and began to deplane the passengers normally. Flight attendants in the rear of the plane later said they did smell some smoke at one point; but that it went away quickly. The aviation mechanic who boarded immediately said that what he observed was simply a tailpipe fire; likely due to a 'wet start'; which went out fairly quickly. He remarked that the ground personnel didn't have the training to make that determination; and thus couldn't provide any information other than that the tail of the airplane was on fire. I do not recall seeing the 'engine fire' hand signal at any time from ground personnel. There is no specific hand signal for an APU fire anyway. Torching; wet starts; and tailpipe fires are not unheard of; and ground personnel should be able to recognize them so as to provide accurate information to flight crews in such an event. The ground crew is to be commended for calling for Airfield Rescue and Fire Fighter equipment right away. Their quick response in the absence of other accurate information on the fire prevented an unnecessary ground evacuation; and had there been a serious fire; would have saved precious time in fighting it.


Second narrative: 'Narrative #2 contained no additional information'


Synopsis: A B757 APU did not start during three attempts after landing; then gate ramp personnel used non standard hand signals to indicate an APU fire but verbally indicated the problem which allowed the crew to call emergency assistance.