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ASN Wikibase Occurrence # 72061
Last updated: 18 June 2020
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Date:21-SEP-2008
Time:12:38
Type:Silhouette image of generic B743 model; specific model in this crash may look slightly different
Boeing 747-337
Owner/operator:Air-India
Registration: VT-EPW
C/n / msn: 24159/711
Fatalities:Fatalities: 0 / Occupants: 182
Other fatalities:0
Aircraft damage: Minor
Category:Serious incident
Location:10 km S of Tokyo-Narita Airport (NRT/RJAA) -   Japan
Phase: En route
Nature:International Scheduled Passenger
Departure airport:Tokyo-Narita Airport (NRT/RJAA)
Destination airport:Delhi-Indira Gandhi International Airport (DEL/VIDP)
Investigating agency: JTSB
Narrative:
On September 21, 2008, at 12:29 Japan Standard Time, a Boeing 747-337, registered VT-EPW, operated by Air India, took off from Narita International Airport on Flight AI307. At about 12:38, while the aircraft was climbing in airspace about 10 km south of Narita International Airport bound for Indira Gandhi International Airport (India), an abnormal noise emanated from the No. 3 engine at an altitude of 15,700 ft, together with an instrument indication showing an abnormality with the engine. The engine in question was then shut down and fuel was jettisoned before the aircraft turned back to Narita International Airport and landed at 13:50.
There were 182 people on board, consisting of the Pilot in Command, 13 other crewmembers and 168 passengers. No one was injured.

PROBABLE CAUSE
It is considered highly probable that this serious incident occurred through the following process. While the Aircraft was climbing after takeoff, nozzle guide vanes of the No. 3 engine LPT STG-2 separated and scattered after fracturing due to intergranular corrosion, and this caused the breakage of the nozzle guide vanes and turbine blades of the downstream stages and eventually damaged the engine.
With regard to the fracture of the nozzle guide vanes due to intergranular corrosion, it is considered highly probable that the inner wall surfaces of the nozzle guide vanes that, unlike the outer surfaces, had no oxidation resistant coating were susceptible to oxidation and corrosion in the grain boundaries, and this led to progressive material degradation and decrease in strength, ultimately resulting in fracture of the vanes starting from the inside walls.

Sources:

http://www.mlit.go.jp/jtsb/eng-air_report/VT-EPW.pdf

Accident investigation:
cover
  
Investigating agency: JTSB
Status: Investigation completed
Duration:
Download report: Final report


Images:

Photo of VT-EPW courtesy AirHistory.net


Tokyo - Narita International (RJAA / NRT)
16 October 2003; (c) Alastair T. Gardiner

Revision history:

Date/timeContributorUpdates
30-Jan-2010 11:02 harro Added

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