5 out of 11 PW engines in IndiGo fleet removed: DGCA

New Delhi: Following three incidents of a commanded In-flight Shut Down (IFSD) of IndiGo aircraft recently, the aviation watchdog, DGCA said that a total of 11 Pratt & Whitney (P&W) engines of the airline's fleet were impacted, however out of these, only five operating engines have been removed till date.

IndiGo's A321 neo aircraft with registration VT-IUJ, operating a flight from Madurai to Mumbai, encountered a critical incident on August 29. During the flight, the crew detected high vibration and low oil pressure in one engine, followed by an engine stall. Upon landing at Mumbai airport, metallic chips were discovered on the oil chip detector.

On the same day, a similar incident unfolded involving IndiGo's A321 neo aircraft with registration VT-IUF, which was en route from Kolkata to Bangalore. The crew reported identical issues with engine 2, leading to a commanded IFSD. The aircraft safely returned to Kolkata, where metallic chips were also found on the oil chip detector of this engine.

On September 3, yet another incident occurred with IndiGo's A320 neo aircraft bearing registration VT-IVI, flying from Amritsar to Delhi. In this case, the crew observed low oil pressure in engine 2, prompting the aircraft to return to Amritsar. An external oil leak was noticed on the affected engine, although there were no reports of vibration or oil chip detection.

Subsequent Boroscopic Inspections (BSI) conducted by IndiGo on the engines involved in these IFSD incidents revealed damage to the Stage 1 blades of the High-Pressure Turbine (HPT) in the engines implicated in the August 29 events. However, no anomalies were detected during the BSI of the engine involved in the September 3 incident at Amritsar.

It's noteworthy that all three engines involved in these incidents had accumulated more than 3,000 hours since their last shop visit (TSLSV).

In response to the blade damage observed in the August 29 incidents, the DGCA took proactive measures, instructing IndiGo to conduct BSI on engines installed on A321 aircraft with more than 3,000 hours TSLSV. Three engines were identified and inspected, but no irregularities were found.

“DGCA took up the matter with Pratt & Whitney (P&W) on September 1 regarding the three incidents of engine failure in quick succession leading to IFSD, demanding OEM’s urgent intervention of the highest level for suitable mitigation,” said the official.

As an added precaution, DGCA also directed IndiGo to perform BSI on engines installed on A321 aircraft with more than 2,500 hours TSLSV. Five engines were identified for inspection, and once again, no abnormalities were detected in any of them

A senior Directorate General of Civil Aviation (DGCA) said that P&W was also advised to identify the probable cause of the HPT blade damage along with the additional inspection(s)/ task(s), recommended by P&W, if any, to detect the deterioration at an early stage to be intimated along with the data of such failures globally and the mitigation measures recommended by P&W to be shared with DGCA.

PW had indicated in July, a recall of 200 engines worldwide, due to HPT hub issues because of an anomaly noted in the hub which could only be detected with an Angular Ultra Sonic Inspection (AUSI) at shop level. In the first phase, the impacted engines were required to be removed before September 15 for the AUSI in a shop.

“A total of 11 engines of the IndiGo fleet were impacted because of this, however out of these, six were a part of the current PW AOG and only five were operating engines which were removed before September 15,” said the DGCA official.

“On September 11, PW indicated that the phase 2 recall is being reviewed by PW which will require removal of up to 600 engines between 2023 and 2026, with most of the removals in Q1 of 2024. PW will issue an SB in the next 60 days with the fleet management action plan,” the official added.