Laying to rest the controversy about whether there was engine fire GoAir flight from Delhi to Bengaluru on February 8, 2017, the Directorate General of Civil Aviation (DGCA) in its enquiry into the engine failure incident of the flight has said that there was no fire on the aircraft. In the report on the incident that was made public this week, the DGCA has said that incorrect installation of an engine part during maintenance and “misinterpretation” of minimum equipment list (MEL) hours by GoAir were the contributory factors to the incident.
The incident occurred on the Airbus A320neo aircraft equipped with Pratt & Whitney’s PW1100G-JM turbofan engines that have faced several performance issues for more than a year causing operational issues to its operators in India — IndiGo and GoAir. As of September 30, Airbus had delivered 22 A320neo aircraft to GoAir, while IndiGo had received 50. As per the DGCA report, as of July 31, 2017, the PW1100G-JM power plant had witnessed 26 premature removals due to combustion chamber distress, 77 premature removals due to the carbon seal bearing distress and two premature removals due to main gearbox failure, worldwide.
MEL hours is the time for which an engine is allowed to operate after a certain red-flag is raised with the equipment. As per the approved MEL by DGCA the flight hours are to be counted as the period of time that begins the moment at which an aircraft begins to move by its own means in preparation for takeoff and ends when the aircraft lands and comes to a complete stop in its parking area. However, as per the Airbus A320 maintenance planning document the flight hours are defined as elapsed time between wheel lift off and touchdown. The report said that the aircraft maintenance engineer, while evaluating the flight hours, had considered only the time period from takeoff to touch down and had not considered the overall engine run time as per the DGCA-approved MEL.
Further, during detailed examination it was identified that the permanent magnetic alternator (PMA) rotor was out-of-position axially and circumferentially on the PMA gear shaft which resulted in the fracture of the PMA bearing cage generating foreign object damage over the period of time which eventfully resulted in to the incident.
The DGCA in its analysis has taken on record that the cabin crew reported to the cockpit that tailpipe fire from left engine – which failed during the flight – was noticed by passengers. However, it added that upon strip examination of the engine, no fire marks were observed, thus ruling out the possibility of fire on the aircraft. It is pertinent to note that in its preliminary report filed to the Ministry of Civil Aviation two days after the incident, the Aircraft Accident Investigation Bureau (AAIB) had noted that there was a fire in the engine due to rubbing and excessive friction of the rotating parts.