Investigations into an engine fire on a Jet Airways ATR 72-500 have been traced back to undetected corrosion of a power turbine blade in the aircraft's right-side Pratt & Whitney PW127M engine.
The aircraft, registered VT-JCL (MSN 791), was operating flight 9W-2839 on 15 June 2016 from Bangalore to Mangalore, when shortly after take-off at 09:59 local time the master caution warning light flashed for about one second when at 4,500 feet.
The cabin crew noticed smoke in the passenger cabin as the aircraft climbed to 6,000 feet, and the flight crew decided to return to Bangalore. Shortly before landing, fire was seen in the right-hand engine. The engine was shutdown and a May-Day call given. The aircraft landed at 10:23 local time. Emergency evacuation was carried out on the runway.
Of the 67 passengers and four crew on board, only three passengers suffered injuries.
In its final investigation report, India's Aircraft Accident Investigation Bureau has classified the incident as 'serious'.
The AAIB says that failure of a power turbine blade likely resulted in heavy vibration of the engine. This damaged the air and oil seals of the turbine shaft bearings and impeller bearings, allowing engine oil to contaminate the bleed air of the right-hand engine, which led to the smoke in the cabin.
The original power turbine blade failure was likely due to corrosion. This would probably have been spotted if specific inspection protocols - that were not required for the engine in question prior to the incident - had been in in place.
Following the incident, the AAIB has recommended that Jet Airways update its routine inspection regimen for its ATR fleet.
Flight Fleets Analyzer shows that VT-JCL is currently in service. It is of 2008-vintage and managed by Aergo Capital.