A safety investigation has found that a Pratt & Whitney PW1127GA-JM engine powering an IndiGo Airbus A320neo suffered extensive internal damage following an in-flight failure in February 2023.
The serious incident occurred on 5 February 2023 while the aircraft (VT-ISE) was operating a scheduled flight from Amritsar to Kolkata, according to the Indian Aircraft Accident Investigation Bureau’s (AAIB) final report.
As the aircraft climbed through approximately 3,000ft, the flight crew heard a loud bang and received multiple indications that the no. 1 engine had failed. The crew followed standard procedures, shut down the affected engine, and returned safely to Amritsar.
“Post arrival, in the initial inspection at Amritsar airport, substantial damage in engine no. 1 was observed by IndiGo’s maintenance personnel and the damaged engine was replaced with a serviceable one,” the AAIB states.
Initial inspections identified damage to blades in the low-pressure turbine (LPT). Subsequent teardown examinations revealed extensive damage across the engine core, including the high-pressure compressor (HPC) stages 4–8, high-pressure turbine (HPT) stages 1–2, and LPT stages 1–3.
The investigation determined that the failure originated from the HPT 2nd stage air seal, where a wire seal was found displaced from its groove. The AAIB concluded that the wire seal was “likely mis-assembled during the last shop visit,” which took place in August 2022.
The report says the wire seal was installed incorrectly, causing the HPT air seal to bulge out of position. When normal thermal expansion further reduced the clearance, the air seal struck the turbine intermediate case.
“The engine examination confirmed that the clashing contact between the HPT 2nd stage air seal and the turbine intermediate case was an unprecedented event,” the AAIB says.
As a result, the bureau concluded that “the serviceability of the engine was the main contributory factor to this serious incident.”
During the incident flight there were 125 passengers and six crew aboard the aircraft.
