GoAir A20N at Delhi on Feb 8th 2017, engine shut down in flight, engine fire confirmed by AIB, denied by DGCA

Last Update: October 16, 2018 / 14:48:34 GMT/Zulu time

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Incident Facts

Date of incident
Feb 8, 2017

Classification
Incident

Cause
Engine fire

Airline
GoAir

Flight number
G8-557

Departure
Delhi, India

Destination
Bangalore, India

Aircraft Registration
VT-WGB

Aircraft Type
Airbus A320-200N

ICAO Type Designator
A20N

A GoAir Airbus A320-200N, registration VT-WGB performing flight G8-557 from Delhi to Bangalore (India) with 187 passengers and 6 crew, was in the initial climb out of Delhi's runway 28 when the crew stopped the climb at 4000 feet due the left hand engine (PW1127) emitting bangs and streaks of flame. The crew shut the engine down and returned to Delhi for a safe landing on runway 28 about 15 minutes after departure.

Passengers reported the engine emitted bangs and streaks of flame for about 30 seconds, then the bangs and flames stopped.

Air Traffic Control reported the crew reported an engine failure during climb out and requested to return.

India's media are reporting that two boys observed flames from the tail of the aircraft as it climbed out, ran into the house and informed their aunt, who called police telling police about an aircraft in flames and emitting unusual noise.

India's Police reported they received calls from three residents of the area about an aircraft engulfed in flames and emitting unusual noise. They called the airport operations center, who in turn called Air Traffic Control, who confirmed the aircraft had already returned for a landing.

India's DGCA reported they are investigating the occurrence. On the previous day while flying from Mumbai to Delhi the crew had received a low oil pressure indication enroute about one hour into the flight, some time later a magnetic chip detector warning came up. Following safe landing the licensed aircraft maintenance engineers (LAME) should have checked the engine due to the magnetic chip detector indication, however, returned the aircraft to service under minimum equipment list requirements permitting it to continue for 10 hours. The aircraft subsequently flew to Leh, could not land there and returned to Delhi, then flew to Guwahati and back. The LAMEs checking the aircraft before departure to Bangalore did not realize that the aircraft had already done 9 hours and would be beyond the 10 hours under MEL upon arrival into Bangalore. The DGCA suspended the license of one of the LAMEs involved pending investigation.

The airline reported they strictly complied with the maintenance regulations by the manufacturer, which permitted up to 10 hours under MEL following a magnetic chip detector indication until the cause of the indication was to be determined.

On Feb 16th 2017 India's AIB reported that immediately after takeoff the crew received a #1 engine low pressure indication followed by an "engine #1 autoshutdown". The crew declared PAN and returned to Delhi for a safe landing on runway 28. There had been a fire inside the engine due to rubbing and excessive friction of the rotating parts (bearings). The occurrence was rated a serious incident and is being investigated by India's AIB.

On Nov 13th 2017 India's DGCA reported that India's AIB was not investigating the occurrence as there had been no fire inside the engine. A malfunction in the gear box led to chips in the engine oil and subsequent low engine oil pressure as well as a magnetic chip detector indication. GoAir, the US NTSB as well as PW examined the engine and found no evidence of any fire. The NTSB stated in their report that a wrong fitment in the main gear box caused a magnetic chip warning.

On Nov 13th 2017 the airline reported the crew had received a low engine oil pressure indication.

On Oct 16th 2018 the DGCA released their final report concluding the probable causes of the incident was:

The cause of the incident was an error during assembly stage as the PMA Rotor was incorrectly installed on gearshift which over the period of time generated FOD and eventfully resulted in to chip warning and subsequently engine shut down.

The misinterpretation of the MEL by the operator regarding flight hours for the release of aircraft with chip warning caused the engine to fail In-flight is a contributory factor.

The DGCA reported the crew operating the aircraft on an earlier sector had received a #1 engine oil chip warning as well as an air bleed maintenance message. The aircraft was returned to service under minimum equipment list requirements with the #1 engine oil chip warning active according to "MEL# 79-09-06A — Eng#1 Oil Chip Detected alert. As per this MEL, in case of an actual alert on one engine, the aircraft may be dispatched for 10 flight hours even with one warning displayed on the EWD."

The aircraft completed three more sectors under MEL before departing for the incident flight. Just when the main wheels became airborne the crew received a red low oil pressure indication for the left hand engine on the ECAM followed by the message engine #1 had failed and an engine #1 stall warning. The crew shut the engine down and returned to Delhi.

A post flight inspection revealed an oil leak from the engine exhaust, the chip detectors of bearings #1-#4 did not contain any chips, however, chips were found in the main gear box chip detector. When the detector was removed oil drained out.

The DGCA also stated: "Tailpipe Fire from Engine No 1 was noticed by passengers and Cabin Crew and the same was reported by Cabin crew to the Cockpit Crew. However during strip examination no fire marks were observed."

The DGCA analysed:

A320 neo aircraft with P & W 1100 G engines had series of failures with their operations after their induction worldwide. As of 31st July, 2017, details of premature removals of PW1100G engines worldwide are as follows:

- 26 Premature removals of engine due combustion chamber distress

- 77 Premature removals of engine due No.3 bearing distress

- Two Premature removals of engine due Main Gear Box failure

- The failed Engine S/N P770153 had logged 2403:06 hours and 1514 Cycles and the No. 2 Engine S/N P770148 had logged 2410:56 hours and 1518 Cycles.

- On further investigation, it was observed that during Boro-Scopic inspection on 11th October 2016 engine S/N P770153 with 1080 Hrs. had evidences of thermal barrier coating missing on bulkhead liner segment. Initially P&W gave disposition and permitted for an inspection interval of 1,350 hours on 12th October 2016. Later on 16th October 2016 they updated it and permitted as per EA 16CCE00 for an inspection interval of 1,500 hours.

- On 31st January 2017, Engine S/N P770153 had logged 2301:36 Hrs. During Boro-Scopic inspection it was observed OBL1/IBL1 Burn-back & Cracking in combustion chamber. P&W gave disposition and permitted for 750 Hour interval.

Subsequently on 8th February 2017, engine S/N P770153 experienced an in — flight shut down shortly after takeoff. It was sent to manufacturer facility for investigation. During detailed examination it was identified that the PMA rotor was not completely seated on its gear shaft which resulted in the fracture of the PMA bearing cage generating FOD over the period of time which eventfully resulted in to the incident.

During further investigation, it was known that the engine chip light warning came during flight while operating the sector (BOM — DEL). At DEL the aircraft was cleared under MEL 79-09-06A (CAT A) for 10 Flight Hours. As per the approved MEL by DGCA the Flight Hours (FHs) are to be counted based on the definition of a flight, i.e. the period of time that begins the moment at which an aircraft begins to move by its own means in preparation for takeoff and ends when the aircraft lands and comes to a complete stop in its parking area. However as per the manufacturer Airbus A320 maintenance planning document the Flight Hours are defined as elapsed time between wheel lift off and touchdown. The AME while evaluating the flight hours had considered only the time period from takeoff to touch down and had not considered the overall engine run time as per the approved MEL.

If the AME would have evaluated the flight hours as per MEL the aircraft would have logged 10:15 Hours by the end of sector DEL-BLR which was above the restriction of MEL. Since the AME had only considered the time in air the aircraft would have logged 08:55Hours only after DEL — BLR sector.

From the above it is inferred that incident occurred due to error at the assembly stage itself. Further, the misinterpretation by the operator regarding the MEL flight hours for the release of aircraft with chip warning caused the engine to fail inflight.