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ASN Wikibase Occurrence # 196006
Last updated: 20 November 2017
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Date:08-DEC-2016
Time:07:18 UTC
Type:Silhouette image of generic DH8D model; specific model in this crash may look slightly different
de Havilland Canada DHC-8-402Q Dash 8
Owner/operator:Flybe
Registration: G-FLBB
C/n / msn: 4255
Fatalities:Fatalities: 0 / Occupants: 27
Other fatalities:0
Airplane damage: None
Location:overhead Dudley, West Midlands, 12nm West of Birmingham -   United Kingdom
Phase: En route
Nature:Domestic Scheduled Passenger
Departure airport:Manchester International Airport (MAN/EGCC)
Destination airport:Jersey Airport, Jersey, Channel Islands (EGJJ)
Narrative:
The aircraft departed at 07:05 hrs UTC on a scheduled flight BE455 from Manchester (EGCC) to Jersey (EGJJ) with four crew and 23 passengers. The aircraft had climbed to FL250 and was on autopilot. Then, approximately two minutes into the cruise, there was a loss in cabin pressurisation indicated by a master warning with associated triple chime alert. The co-pilot noted the warning and immediately called for oxygen and donned his oxygen mask. The commander handed control to the co-pilot, directed him to initiate a descent and inform ATC. The co-pilot started the descent using the autopilot and then disengaged the autopilot to manually fly a descent at 3,500 fpm. By this time the commander had donned his oxygen mask and re-took control, reengaged the autopilot and declared a MAYDAY. The aircraft was stabilised at FL100. Satisfied there were no structural issues with the aircraft, the commander cancelled the MAYDAY and obtained clearance from ATC to continue to Jersey maintaining FL100. Whilst the crew were dealing with the situation the commander was having difficulties with his oxygen mask microphone so swapped masks. The crew completed the quick reference handbook (QRH) actions and removed their oxygen masks. They then informed and reassured the passengers about the situation over the PA. The flight continued at FL100 and landed at Jersey without further incident. A normal disembarkation was carried out and there were no injuries to the passengers or crew.

The cause of the pressurisation problem was the outflow valve, which the evidence suggests had a history of being causal or contributory to pressurisation problems in other aircraft. It also appears that the problem did not manifest itself during post installation functional checks as, shown by its fitment to G-KKEV and G-FLBB. In this situation it is sometimes difficult for engineering staff to reject an item which, when subjected to normal checks detailed in the AMM, meets the requirements for release to service.

It is probable that the loss of pressurisation was gradual but maintained just within system limits during the climb to FL250. When the aircraft was established in the cruise at FL250 the cabin pressure altitude continued to climb over a period of two minutes until the warning level was reached. Although by no means debilitating in this case, it shows how quickly the flight deck crew appeared to suffer the early signs of hypoxia.

Sources:

1. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/615527/AAIB_Bulletin_6-2017.pdf
2. http://avherald.com/h?article=4aa19de4&opt=0

Accident investigation:
cover
Investigating agency: AAIB
Status: Investigation completed
Duration: 183 days (6 months)
Accident number: EW/G2016/12/01
Download report: Summary report

Images:


Revision history:

Date/timeContributorUpdates
09-Jun-2017 07:51 harro Added
09-Jun-2017 08:14 harro Updated [Narrative]
15-Sep-2017 23:13 Dr. John Smith Updated [Location, Departure airport, Destination airport, Source]

Corrections or additions? ... Edit this accident description