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ASN Wikibase Occurrence # 186543
Last updated: 28 November 2021
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Time:16:49 CHST
Type:Silhouette image of generic B738 model; specific model in this crash may look slightly different
Boeing 737-809 (WL)
Owner/operator:China Airlines
Registration: B-18609
MSN: 28407/161
Fatalities:Fatalities: 0 / Occupants: 122
Other fatalities:0
Aircraft damage: None
Location:180nm northwest of Guam -   Guam
Phase: En route
Nature:Passenger - Scheduled
Departure airport:Guam International Airport (GUM/PGUM)
Destination airport:Taiwan Taoyuan International Airport (TPE/RCTP)
Investigating agency: ASC
China Airlines flight CI025 turned back to Guam International Airport after a cabin pressurisation issue.
After the aircraft, a Boeing 737-800, climbed up to an altitude of 37,000 feet, a caution message "Auto Fail/Unscheduled Pressurization Change" showed up on the instrument panel. The flight crew then performed manual control procedures according to the Quick Reference Handbook. The abnormal cabin altitude persited, forcing the flight crew to immediately perform an emergency descent and turn back to Guam. A safe landing was made on runway 06R about 40 minutes later.

Findings published by the ASC:
Findings related to probable causes: A gear pin of cabin pressure system outflow valve was broken so that the outflow valve could not be controlled which resulted in abnormal cabin pressure and air turned back to Guam.

Findings related to the risks: During the Operator's so-called "the contents of the Fault Isolation Manual is incomplete" event happene [sic: happening?], the Aircraft On Ground team did not contact the Boeing for professional and effective recommendations. After the end of rescue [sic: repair?], the team did not actively inquire about the cause of failure message during troubleshooting. This indicates that the China Airlines should implement the execution of maintenance management rules.

Four safety recommendations were raised.


Accident investigation:
Investigating agency: ASC
Status: Investigation completed
Download report: Final report
Safety recommendations:

Safety recommendation ASC-ASR-17-06-001 issued 4 June 2017 by ASC to China Airlines
Safety recommendation ASC-ASR-17-06-002 issued 4 June 2017 by ASC to China Airlines
Safety recommendation ASC-ASR-17-06-003 issued 4 June 2017 by ASC to CAA Taiwan
Safety recommendation ASC-ASR-17-06-004 issued 4 June 2017 by ASC to CAA Taiwan


Photo of B-18609 courtesy

Hong Kong - International (VHHH / HKG)
13 January 2003; (c) LRS747

Revision history:

18-Apr-2016 15:12 AF5541 Added
18-Apr-2016 15:14 harro Updated [Source, Narrative]
18-Apr-2016 15:15 harro Updated [Registration]
09-Jun-2016 04:14 AF5541 Updated [Destination airport]
04-Jun-2017 07:45 harro Updated [Narrative]
04-Jun-2017 07:50 harro Updated [Time]
04-Jun-2017 18:03 Aerossurance Updated [Source, Narrative]

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