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ASN Wikibase Occurrence # 223535
Last updated: 9 September 2021
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Time:c. 05:00 UTC
Type:Silhouette image of generic A320 model; specific model in this crash may look slightly different
Airbus A320-232
Registration: 9V-TAU
MSN: 4561
Fatalities:Fatalities: 0 / Occupants: 184
Other fatalities:0
Aircraft damage: None
Location:near Taiwan Taoyuan International Airport (RCTP) -   Taiwan
Phase: Approach
Nature:Passenger - Scheduled
Departure airport:Singapore-Changi International Airport (SIN/WSSS)
Destination airport:Taipei-Taiwan Taoyuan International Airport (TPE/RCTP)
Investigating agency: ASC
Scoot flight TR996, an A320-232 aircraft, took off from Singapore Changi International Airport (WSSS) for Taiwan Taoyuan International Airport (RCTP). During approach to RCTP, at an altitude of about 14,000 ft, the excessive cabin altitude waring was shown in the cockpit.
The pilots immediately donned oxygen masks and manually deployed cabin oxygen masks. The aircraft continued the approach to RCTP and landed safely.

Findings related to probable causes
1. The two automatic cabin pressurization systems had failed one after another during descent. This resulted in the aircraft losing the
automatic cabin pressurization function.
2. After the failure of both automatic cabin pressurization systems, the flight crew controlled the cabin pressure manually, as required by the ECAM checklist. The captain misunderstood the direction of operation for the MAN V/S CTL toggle switch and the corresponding effect on the position of outflow valve, and provided the wrong instruction to the first officer. The first officer did not recognize the incorrect
instruction to operate the outflow valve in the direction of opening, causing the cabin altitude to rise rapidly and eventually exceeding the cabin altitude limitation.


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


Photo of 9V-TAU courtesy

Hong Kong - International (VHHH / HKG)
27 January 2019; (c) Anton Homma

Revision history:

26-Mar-2019 18:40 harro Added
23-Jul-2020 15:51 harro Updated [Source, Narrative, Accident report, ]

Corrections or additions? ... Edit this accident description