The auxiliary power unit (APU) of an Air India Airbus A321 (TV-TVG), located in the tail section, caught fire at Delhi's Indira Gandhi Inte.

An Auxiliary Power Unit, commonly referred to as APU, is a small turbine engine usually located in the tail section of an aircraft. Unlike the main engines that provide thrust for flight, the APU is designed to provide energy for functions other than propulsion.

An Air India flight was grounded shortly after landing in New Delhi after a fire broke out in its auxiliary power unit on Tuesday. Passengers were disembarking flight AI315 from Hong Kong when the fire was detected,