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ASN Wikibase Occurrence # 247162
Last updated: 15 October 2021
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Date:27-DEC-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
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
Narrative:
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.

PROBABLE CAUSE:
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.

Sources:

JTSB

Accident investigation:
cover
  
Investigating agency: ARAIC
Status: Investigation completed
Duration: 9 months
Download report: Final report
Other occurrences involving this aircraft

2 Oct 2015 JA8947 All Nippon Airways ANA 0 Osaka International Airport/Itami (ITM/RJOO) sub


Images:

Photo of JA8947 courtesy AirHistory.net


San Bernardino - International (KSBD / SBD)
11 October 2019; (c) Dan Stijovich

Revision history:

Date/timeContributorUpdates
27-Jan-2021 18:43 harro Added

Corrections or additions? ... Edit this accident description