B767 Undifferentiated or Other Model
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
General None Reported / Taken
Human Factors; Procedure
I was doing my rounds of the aircraft here in ZZZ. As I drove by our pre-flighted Aircraft X; I could hear an APU running and stairs were up to the aircraft. As I walked up to the aircraft and entered; I noticed the aircraft was sealed from the pre-flight; I broke the seal and confirmed via EICAS indication that the APU was running. The pre-flight crew typically completes the pre-flight between XA-XA:30L. The aircraft was pre-flighted and sealed and left with the APU running for 2.75 hours with no one to monitor for fire events and EGT (Exhaust Gas Temperature) temps; this is a severe hazard and had there been a fire event there would have been no one to activate the fire bottle or follow proper procedures. [Recommend] following proper procedures and if no one is left in the cockpit to monitor the APU; please shut it down.
[I] was told that maintenance filed a report saying they found the APU running on Aircraft X after we performed a pre-flight on [date]. To the best of my recollection I completed a full shutdown checklist which includes turning off the battery switch.
Maintenance Supervisor and a Captain reported an aircraft was left unattended with the Auxiliary Power Unit running.