Loss of pressurization Serious incident Airbus A320-211 JA8947, Thursday 27 December 2001
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Date:Thursday 27 December 2001
Time:11:45 LT
Type:Silhouette image of generic A320 model; specific model in this crash may look slightly different    
Airbus A320-211
Owner/operator:All Nippon Airways - ANA
Registration: JA8947
MSN: 685
Year of manufacture:1997
Engine model:CFMI CFM56-5A1
Fatalities:Fatalities: 0 / Occupants: 55
Other fatalities:0
Aircraft damage: None
Category:Serious incident
Location:75 km NW of Toyama City -   Japan
Phase: En route
Nature:Passenger - Scheduled
Departure airport:Niigata Airport
Destination airport:Okinawa-Naha Airport
Investigating agency: ARAIC
Confidence Rating: Accident investigation report completed and information captured
ANA flight 465 experienced a drop in cabin air pressure while en route at FL350. The flight crew carried out an emergency descent and diverted to Osaka.

In this serious incident, it is estimated that while the aircraft was operating at an altitude of 35,000ft for the first time since the replacement of the safety valves, the gate of a safety valve opened at a differential pressure lower than the specified limit and this open condition persisted. As a result there was a decrease in cabin pressure. It is estimated that the opening of the gate of the safety valve below the specified pressure limit and the persistence of its open condition was caused mutually by the existence of anomalies in the stem assembly and an inappropriate shim adjustment, both at the time of manufacture of the said valve.

Accident investigation:
Investigating agency: ARAIC
Report number: 
Status: Investigation completed
Duration: 9 months
Download report: Final report



History of this aircraft

Other occurrences involving this aircraft

2 October 2015 JA8947 All Nippon Airways - ANA 0 Osaka International Airport/Itami (ITM/RJOO) min
Engine failure

Revision history:

27-Jan-2021 18:43 harro Added

Corrections or additions? ... Edit this accident description

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