Even as the country's aviation regulator, the Directorate General of Civil Aviation (DGCA), extended its deadline to replace or modify all problematic engines across the fleet of Airbus A-320 and A321 NEO aircraft to May 31, an IndiGo flight from Pune to Jaipur was diverted after the pilot observed an engine vibration message on Friday.
All passengers were landed safely. It was the latest in a series of engine related incidents in the low-cost carrier.
IndiGo was one of the first airlines to introduce Airbus A320 NEO to its fleet, taking in first deliveries of the model in 2016. Since the induction, A320 NEO aircraft has suffered several engine failures. Over 20 engine related incidents have happened since 2018.
The DGCA has decided to give more time to the airline as hundreds of passengers would be at the receiving end in case of aircraft getting grounded.
According to the DGCA, in October 2019 alone there were four incidents of IndiGo Airbus A320 NEO aircraft being forced to turn back due to engine shutdown during flight. The failure of third stage LPT (low pressure turbine) blades were found to be cause for these events, which the authority dubbed as a “serious concern”. In all four cases, the engines affected were unmodified Pratt & Whitney engines powering the A320 Neo.
The DGCA issued various orders containing directions to IndiGo to address the issues. Meanwhile, based on investigation of events related LPT damage, the manufacturer has identified that fracture of mild turbine frame (MTF) piston seal is contributing to 50 per cent of LPT events.
"To prevent the potential damage to the LPT third stage blades due to fracture of MTF pistol seal, M/s P&W issued service bulletin on 16 December 2019, to provide inspection criteria to perform a boroscopic inspection on the pistol seal for wear. This repeat inspection of pistol seal shiplap on engines having unmodified parts is considered to be effective in identifying engines before it fails on wing as a short term measure," the DGCA order said while adding that a number of engines have been removed based on these inspections.
