Incident Summary
On 21 January 2019, an IndiGo Airbus A320-271N (registration VT-ITQ) operating scheduled flight 6E-451 from Lucknow to Jaipur suffered an engine stall shortly after departure. The aircraft was at flight level 120 when the crew heard a loud bang, followed by an engine stall warning on the ECAM, along with exceedances of exhaust gas temperature and high vibration indications. The crew executed the ECAM procedures and decided to return to Lucknow, where the aircraft landed safely at 1158 UTC. There were no injuries to the 120 occupants, including four cabin crew.
Aircraft and Crew Information
The aircraft, an Airbus A320neo with Pratt & Whitney PW1127G-JM engines, was manufactured in 2017 and had accumulated 6,232 hours and 52 minutes of flight time. The pilot in command held an ATPL with 3,186 hours total experience (2,943 on type). The co-pilot also held an ATPL with 2,212 hours total (1,887 on type). Both crew members had undergone pre-flight medical and breathalyzer tests with negative results.
Sequence of Events
After an uneventful takeoff from Lucknow at approximately 1107 UTC, the aircraft climbed normally. At 1128 UTC, while at FL120, a loud bang was heard. The ECAM displayed ENG 2 STALL, followed by ENG 2 EGT OVERLIMIT and ENG 2 HGH VIB. Engine parameters showed N1 and N2 vibration readings of 7 and 10 respectively, and EGT exceeded 1000°C. The crew followed the QRH/FCOM checklists for engine stall and vibration, and decided to divert back to Lucknow. They informed ATC, obtained clearances, and landed at 1158 UTC without declaring an emergency. The aircraft taxied to the bay, and passengers disembarked normally.
Damage to Engine #2
Post-flight visual inspection of the right engine (Engine #2) revealed damage to all Low Pressure Turbine (LPT) third stage blades, which were fractured from the tip. Detailed borescope and tear-down examination identified additional damage: nicks on HPC stage 5 rotor blades, worn HPC stage 6 bore, cracked combustion chamber outer seal, dented HPT stage 1 hub air seal, unserviceable HPT stage 1 blades, impact damage to the LPT shaft, damaged LPT stage 1 and 3 outer air seal honeycomb segments, impact damage to LPT stage 2 and 3 vanes, severely damaged LPT case, impact damage to LPT stage 1 and 2 blades, and impact damage to the turbine exhaust case. No other aircraft systems were affected.
Investigation
The occurrence was classified as a serious incident under Rule 11(1) of the Aircraft (Investigation of Accidents and Incidents) Rules, 2017. Flight data recorder and cockpit voice recorder data were analyzed. The report noted that weather had no relevance to the incident. No probable cause has been stated in the source.