Scoot A319 near Singapore on Jun 14th 2019, loss of cabin pressure

Last Update: April 2, 2020 / 20:59:45 GMT/Zulu time

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Photo of Scoot Airlines 9V-TRB, Airbus A319 — Scoot Airlines 9V-TRB, Airbus A319 (Photo credit: Alec BHX/KKC / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Jun 14, 2019

Classification
Incident

Cause
Loss of cabin pressure

Airline
Scoot Airlines

Flight number
TR-387

Departure
Angeles, Philippines

Destination
Singapore, Singapore

Aircraft Registration
9V-TRB

Aircraft Type
Airbus A319

ICAO Type Designator
A319

A Scoot Airbus A319-100, registration 9V-TRB performing flight TR-387 from Angeles (Philippines) to Singapore (Singapore) with 129 people on board, was descending towards Singapore when the flight crew donned their oxygen masks, declared PAN PAN reporting excessive cabin altitude and initiated an emergency descent to 9000 feet. The aircraft continued to Singapore for a safe landing on runway 20C about 23 minutes after declaring PAN PAN.

Singapore's AAIB rated the occurrence a serious incident and opened an investigation.

In late March 2020 Singapore's AAIB released their final report concluding the probable cause of the occurrence finally rated an incident were:

- The likely cause of the excessive cabin altitude was a corruption of LFE (landing field elevation) in the CPC. The CPC manufacturer believed that the corruption arose from a fatigue solder joint on the CPC circuit board.

- There had been past occurrences of excessive cabin altitude that were caused by a corruption of LFE value in the CPC, of which one was determined to have likely been caused by a fatigue solder joint, similar to this occurrence.

The AAIB reported the aircraft was descending through about FL320, when the captain (31, ATPL, 6,699 hours total, 6,467 hours on type), pilot flyin, felt a noticeable change of cabin pressure on her ears and queried the first officer (37, ATPL, 3,517 hours total, 924 hours on type). Descending through FL290 the crew observed a slow increase in cabin altitude, which was climbing at about 550fpm although the aircraft was descending at 2000 fpm. The crew increased the descent to 4000 fpm, as the climb of the cabin altitude was not normal. The crew requested further descent and was cleared to FL260 then FL200. Just when the first officer read back the clearance for FL200 the cabin altitude warning activated. The crew donned their oxygen masks and initiated an emergency descent to 9000 feet increasing the rate of descent to about 5300 fpm initially. The crew later reported they observed 13500 feet cabin altitude as the peak altitude, the passenger oxygen masks were not released.

The AAIB reported: "The examination revealed that a corrupted LFE value had triggered CPC 2 to activate the “landing at high altitude” procedure and was increasing the cabin altitude towards a higher LFE value than the correct one. The corrupted LFE value used by the CPC could not be determined."

The AAIB analysed: "CPC 2 was in control during the incident. The CPC processing logic was working as designed during the incident. The test by the CPC manufacturer conducted on the CPC 2 revealed that the incorrect increase of the cabin altitude arose from LFE value that was corrupted inside the CPC. The corruption of the LFE value was most likely caused by a fatigue solder joint on the CPC circuit board. "