Ibex CRJ7 at enroute on Apr 17th 2016, loss of cabin pressure

Last Update: December 26, 2017 / 15:29:41 GMT/Zulu time

Bookmark this article

Photo of Ibex Airlines JA06RJ, Canadair CRJ-700 — Ibex Airlines JA06RJ, Canadair CRJ-700 (Photo credit: lasta29 / Flickr / License: CC by)

Incident Facts

Date of incident
Apr 17, 2016

Classification
Incident

Cause
Loss of cabin pressure

Airline
Ibex Airlines

Flight number
FW-84

Departure
Fukuoka, Japan

Destination
Komatsu, Japan

Aircraft Registration
JA06RJ

Aircraft Type
Canadair CRJ-700

ICAO Type Designator
CRJ7

An Ibex Airlines Canadair CRJ-700, registration JA06RJ performing flight FW-84 from Fukuoka to Komatsu (Japan) with 40 people on board, was on approach to Komatsu when the crew went around due to weather (high winds) and decided to return to Fukuoka. The aircraft climbed to FL400 and was enroute about 35nm north of Hiroshima (Japan) and about 140nm northeast of Fukuoka when the crew initiated an emergency descent due to the loss of cabin pressure as result of failure of both air conditioning systems on board. The aircraft landed safely back in Fukuoka about 2:15 hours after departure.

Japan's TSB reported the crew received a low cabin pressure indication after one of the engine (CF34) bleed air systems failed.

On Oct 19th 2016 the US NTSB reported, that they have assigned an accredited representative to join the investigation by the JTSB, the NTSB represents the state of design and manufacture of the bleed air temperature sensors. The NTSB reported the crew received an engine air bleed bulb failure message followed by a cabin low pressure indication, considered the weather at destination as unsuitable and returned to Fukuoka.

On Dec 26th 2017 Japan's Transport Safety Board (JTSB) released their final report concluding the probable causes of the serious incident were:

In this serious incident, it is highly probable that both bleed air systems stopped supplying the bleed air and the cabin altitude rose, because the Anti-Ice and Leak Detection Controller (AILC) had detected the air leaks on both bleed air systems.

It was not possible to determine why the AILC detected the bleed air leaks, although it was somewhat likely that there was any malfunction in the AILC, the bleed air leaked actually, or the sensing elements had any malfunction.

The JTSB reported the left hand bleed air system failed first, the crew performed the descent as required by the AOM, shortly after beginning to read the related checklist the right hand bleed air system indicated failed, too. The crew declared emergency, donned their oxygen masks and initiated an emergency descent. While descending through FL170 the cabin altitude climbed through 10,000 feet triggering the cabin altitude warning. The passenger oxygen masks did not deploy. The aircraft subsequently continued the return to Fukuoka.

The JTSB analysed:

According to the records of the MDC and the AILC, the respective bleed air leak on both systems was detected as an individual phenomenon. It is highly probable that because the AILC had detected the left bleed air leak first, the AILC closed the left PRSOV and stopped the left bleed air supply. It is highly probable that because the AILC had detected the right bleed air leak four minutes later, the AILC closed the right PRSOV and stopped the right bleed air supply. It is highly probable that because the bleed air supply of both systems had stopped for these reasons, the cabin altitude rose.

Since the area that the AILC detected the bleed air leak from the left system was in the same area, it is somewhat likely that the bleed air was actually leaked from the ducts or that the sensing elements caused malfunctions due to the heat radiation from the ducts. However, at the reproductive confirmation on the investigations regarding the ducts and the Aircraft, defects and abnormalities were not confirmed.

Since the common part to monitor the bleed air leaks is AILC, it is somewhat likely that AILC caused malfunctions, but defects and abnormalities were not confirmed on this investigation.

Since any defect and abnormality were not confirmed on the investigations of the Aircraft, the sensing elements and the AILC, it was not possible to determine why the AILC has detected the bleed air leak.

Since the area that the AILC detected the bleed air leak from the right system was in the different area on both channels, it is somewhat likely that the AILC had malfunctioned. However, any defect and any abnormality could not be confirmed on the investigations regarding the AILC. Furthermore, since on the investigations of the Aircraft and the sensing elements, any defect, any abnormality and the reproduction of the leak were not confirmed, it was not possible to determine why the AILC detected the bleed air leak.

Metars Komatsu:
RJNK 170200Z 19030G42KT 9999 FEW015 27/10 Q0994
RJNK 170100Z 17031G49KT 9999 FEW010 SCT050 24/11 Q0994
RJNK 170000Z 18033G53KT 9999 -RA FEW015 SCT030 BKN050 21/10 Q0995
RJNK 162300Z 18027G44KT 140V220 9999 -RA FEW030 SCT070 OVC100 20/10 Q0996
RJNK 162200Z 19027G45KT 160V220 9999 -RA FEW040 SCT070 OVC100 21/09 Q0997
RJNK 162100Z 18019G33KT 150V210 9999 -RA FEW040 SCT070 OVC100 18/10 Q0999
RJNK 162000Z 18020G33KT 9999 -RA FEW040 BKN100 OVC120 18/09 Q1002

Metars Fukuoka:
RJFF 170200Z 29016KT 9999 FEW025 SCT040 19/09 Q1009 RMK 1CU025 3CU040 A2981
RJFF 170130Z 30012KT 270V330 9999 FEW025 19/09 Q1008 RMK 1CU025 A2979
RJFF 170104Z VRB14KT 9999 FEW025 20/09 Q1008 RMK 1CU025 A2978
RJFF 170100Z VRB04KT 9999 FEW025 20/10 Q1008 RMK 1CU025 A2978
RJFF 170030Z 24007KT 210V280 9999 FEW025 19/09 Q1008 RMK 1CU025 A2977
RJFF 170000Z 28007KT 230V310 9999 FEW025 18/08 Q1008 RMK 1CU025 A2978
RJFF 162330Z 26009KT 210V300 9999 FEW030 18/08 Q1008 RMK 2CU030 A2977
RJFF 162300Z 25007KT 210V280 9999 FEW020 SCT035 17/08 Q1008 RMK 1CU020 4CU035 A2977