GoAir A320 at Delhi on Jun 21st 2017, bird strike, wrong engine shut down and restarted

Last Update: February 4, 2019 / 18:07:41 GMT/Zulu time

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Incident Facts

Date of incident
Jun 21, 2017

Classification
Incident

Cause
Bird strike

Airline
GoAir

Flight number
G8-338

Departure
Delhi, India

Destination
Mumbai, India

Aircraft Registration
VT-GOS

Aircraft Type
Airbus A320

ICAO Type Designator
A320

A GoAir Airbus A320-200, registration VT-GOS performing flight G8-338 from Delhi to Mumbai (India) with 158 passengers and 6 crew, was in the takeoff roll at about 115 KIAS out of Delhi's runway 09 when a bird struck the right hand engine (CFM56) causing vibrations and abnormal sounds. The crew continued takeoff, stopped the climb at 3000 feet, shut the left hand engine down and decided to return to Delhi. The crew subsequently recognized they had shut the wrong engine down, restarted the left hand engine and reduced the right hand engine to idle. The aircraft landed safely on runway 10 about 20 minutes after departure.

A replacement Airbus A320-200 registration VT-WAF reached Mumbai with a delay of 2.5 hours.

India's media are reporting the crew allegedly continued the flight following the bird strike and only returned to Delhi after 45 minutes. India's DGCA rated the occurrence a serious incident, opened an investigation against both pilots and de-rostered them.

On Jun 23rd 2017 India's media changed their coverage now reporting quoting "a source" (raising the impression that the source might have been inside the DGCA), that the crew "allegedly" shut down the good, unaffected engine (CFM56) after a bird had been ingested by the other engine during takeoff. The crew soon recognized their mistake while maintaining 2000 feet, restarted the shut down engine and were lucky that the bird stricken engine had not lost thrust.

Radar data show the aircraft became airborne at 11:11L (05:41Z), climbed to 3000 feet, briefly reached a maximum speed of 228 knots over ground and touched down at 11:31L (06:01Z). The aircraft was scheduled to depart at 10:45L, 45 minutes prior to the actual landing back.

The occurrence aircraft resumed service about 11.5 hours after landing back.

On Feb 4th 2019 India's DGCA released their final report concluding the probable cause of the incident (!!) was:

Incident was caused by incorrect identification of engine affected with high vibration followed by non-adherence to recommended procedures, lack of situational awareness, poor Cockpit Resource Management and poor handling of aircraft during emergency subsequent to bird strike.

The captain (64, ATPL, 23,507 hours total, 13,187 hours on type) was pilot flying, the first officer (30, CPL, 936 hours total, 730 hours on type) was pilot monitoring.

The DGCA described the sequence of events:

During take-off roll, crew experienced abnormal sound & vibrations. Being unsure of the reason for vibrations, First Officer enquired PIC for rejecting take-off but PIC decided to continue for take-off as he was not sure that the aircraft would stop within the available runway, if executed rejected take-off, and probably wanting to investigate the problem after getting airborne. ECAM advisory for high N1 vibration of Engine # 2 came at 05:40:32 hrs as value of N1 vibration of Engine # 2 reached above specified limit, i.e. ¡Ý 6. The vibration advisory was not called out by First Officer. Aircraft IAS was 129 knots at this stage. Values of V1, VR & V2 were calculated to be 146 knots, 146 knots and 147 knots respectively.

After getting airborne, cockpit crew noticed the problem of high engine vibration but assessed the situation incorrectly. As a result, they shut down the Engine # 1 (unaffected engine) by putting its MASTER- OFF at 05:41:48 hrs and increased power to TO/GA on the Engine # 2 (affected engine).

Crew declared emergency due to engine problem to ATC, Delhi at 05:41:50 hrs and requested immediate turn back to Delhi for landing, which was granted by ATC.

During subsequent conversations while climbing, wherein PIC inquired about the engine vibrations, First Officer repeatedly prompted PIC about Engine # 1 vibration out of limits.

The aircraft was climbing on affected engine¡¯s power varying from TO/GA to CLIMB while the unaffected engine was shutdown. On directions from ATC, aircraft stopped climbing at 05:43:13 hrs at around 3330 ft altitude. Subsequently, PIC recognized that the Engine # 2 is affected with high vibrations. Crew realized their mistake at 05:43:42 hrs about shutting down the wrong engine and decided to switch on the unaffected engine.

Crew put MASTER-ON of the unaffected engine at 05:43:49 hrs and attempted to start the engine. While attempting the start of Engine # 1, the Engine # 2 power was put on IDLE at 05:44:15 hrs. At this stage, aircraft was flying at an altitude of around 3332 ft with only affected engine running on IDLE. The attempt to start Engine # 1 resulted in ¡®Start Valve Fault¡¯ at 05:44:57 hrs. Crew took appropriate action to rectify the same. Engine # 2 power was put on CLIMB again from 05:45:42 hrs up to 05:45:59 hrs.

First Officer confirmed at 05:45:58 hrs that Engine # 1 is available. Engine # 2 was put to IDLE at 05:46:00 hrs and Engine # 1 put to CLIMB on 05:46:01 hrs. Aircraft was at 3024 ft altitude at this stage.

As per the occurrence report, the weather, after take-off, was very turbulent and the autopilot was not holding. Autopilot was disengaged at 05:41:50 hrs and several times from 05:45:43 hrs to 05:46:44 hrs.

In the process of starting Engine # 1, aircraft lost considerable amount of energy which probably combined with manual handling of aircraft, immediately resulted in activation of protective ALPHA FLOOR at 05:46:01 hrs which lasted for 28 seconds. Crew carried out appropriate action and ALPHA FLOOR got deactivated at 05:46:29 hrs at 2600 ft altitude. ECAM advisory for high N1 vibration of Engine # 2 went off at 05:46:37 hrs.

Value of N1 vibration of Engine # 2 was above the specified limits (¡Ý 6) for approximately six minutes. The maximum value of N1 vibration of Engine # 2 recorded was 9.9.

While in approach for the landing at 05:50:57 hrs, crew requested ATC for Go-around as they were too high on a glide. The same was granted by ATC immediately. Crew initiated Go-around at approximately 05:51:07 hrs with Engine # 1 on FLX-MCT and Engine # 2 on IDLE.

In the second approach, aircraft landed uneventfully on Runway 10 at Delhi at 05:58:36 hrs with Engine # 2 on IDLE. No injury to any person was reported in the incident.

While taxiing to the allocated stand for parking, not realizing their position with respect to parking stand, crew took wrong turn. Crew of Follow Me # 8 realized the same and communicated to Surface Movement Control (Ground) to ask aircraft to hold the position and switch off the engines. Aircraft held its position and switched off both the engines at 06:01:40 hrs. Subsequently, aircraft was towed to reposition it correctly on the allotted parking stand.

On arrival, during physical inspection, the blood stains were observed spread on the acoustic panel of Engine # 2 & damage was observed on the tips of the leading edge of two fan blades i.e. blade # 21 & # 22.

As crew were unaware about the Bird Strike, no information was given to ATC, Delhi for the same during the incident flight. Identification of species of struck bird could not be carried out as only blood stains were observed on acoustic panel of Engine # 2.

Following the return the crew operated the flight on the replacement aircraft.

The DGCA analysed:

Operational aspects:

- Both the crew members were medically fit, had adequate rest and found to be within FDTL limits before they operated flight on June 21st 2017. Medical fitness & FDTL is not considered as a factor to this incident.

- Crew had completed ¡®Before Take-off checks¡¯.

- Aircraft suffered with bird strike on engine # 2 while take-off roll at 5:40:29 hrs at around 115 knots IAS. V1, VR & V2 were calculated to be 146 knots, 146 knots & 147 knots respectively. Both crew observed abnormal sound & vibrations in cockpit. At 5:40:32 hrs at 129 knots IAS, ECAM Advisory with regard to N1 vibrations of Engine # 2 was displayed, which was not called out by First Officer. However, First Officer enquired PIC for rejecting take off.

- PIC could have rejected take-off as speed was well below V1, but as the aircraft was in high speed range he was not sure that the aircraft would stop within the available runway, if executed rejected take-off. Having no input with regard to engine # 2 vibrations, and probable intention to investigate the problem after getting airborne, PIC continued for take-off.

- During take-off roll, there was no input from First Officer regarding high engine vibrations and further there was no red ECAM warning and amber ECAM caution. PIC¡¯s decision to continue for take-off, in absence of any abnormal input from First Officer, was in line with FCTM guidelines.

- Crew did not complete Take-off checks & After Take-off checks.

The DGCA analysed that the left engine was relighted with the assistance of the starter, the "starter assisted relight" procedure was carried out.

The DGCA analysed: "In the process of starting of Engine # 1, crew did not monitor the decreasing speed of the aircraft; resulting into considerable loss of energy under the deficiency of the power for a brief period combined with the handling the aircraft without autopilot, probably lead to activation of ALPHA FLOOR at 3024 ft and 139 knots IAS. Due to activation of ALPHA FLOOR aircraft got TO/GA thrust from both the engines as the autothrust was already engaged. ¡®TO/GA LOCK¡¯ appeared after 24 seconds of activation of ALPHA FLOOR."
Incident Facts

Date of incident
Jun 21, 2017

Classification
Incident

Cause
Bird strike

Airline
GoAir

Flight number
G8-338

Departure
Delhi, India

Destination
Mumbai, India

Aircraft Registration
VT-GOS

Aircraft Type
Airbus A320

ICAO Type Designator
A320

This article is published under license from Avherald.com. © of text by Avherald.com.
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