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ASN Wikibase Occurrence # 152711
Last updated: 6 September 2021
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Date:05-MAR-2011
Time:06:50 UTC
Type:Silhouette image of generic A320 model; specific model in this crash may look slightly different
Airbus A320-214
Owner/operator:Finnair
Registration: OH-LXL
MSN: 2146
Fatalities:Fatalities: 0 / Occupants: 146
Other fatalities:0
Aircraft damage: None
Location:over Island of Öland -   Sweden
Phase: En route
Nature:Passenger - Scheduled
Departure airport:Helsinki-Vantaa Airport (HEL)
Destination airport:London-Heathrow Airport (LHR/EGLL)
Narrative:
A pressurisation failure led to a serious incident on Finnair flight AY831. An Airbus A320-214 airliner, registration OH-LXL, was on a scheduled flight from Helsinki to London. The aircraft departed with Bleed No.1 inoperative according to Minumum Equipment List (MEL).The aircraft was flying in Swedish airspace, north of the Island of Öland at Flight Level 360 with both air conditioning packs supplied by Bleed No.2 and cross bleed valve opened. Ten minutes after reaching cruise altitude, the remaining bleed (Bleed No.2) failed. As a result of this, the flight crew had to execute a rapid descent to a safe altitude.

This serious incident was caused by rising Cabin Pressure which, in turn, could have been the result of a failure of the Fan Air Valve (FAV) or Temperature Control Thermostate (TCT) grid filter clogging in the right engine's bleed air system (Bleed No.2).
With the other system being inoperative for flight, the cooling capacity of only one system proved insufficient. The pre-cooled air was too hot, therefore the temperature sensor of the system worked as per its design and shut off the overheated system.

The Safety Investigation Authority, Finland recommends that the EASA oblige Airbus to compile all engine bleed air failure-related emergency procedures that pilots use, and display the complete set of instructions on the ECAM.

The Safety Investigation Authority, Finland also recommends that the EASA oblige Airbus to amend the Operations Engineering Bulletin (OEB) in a manner that clearly segregates the procedures for prior to the flight and during the flight. Additionally Airbus needs to assure that all the appropriate actions included in the OEB are in line with Quick Reference Handbook (QRH).

Sources:

http://www.turvallisuustutkinta.fi/en/Etusivu/1347274036437


Images:

Photo of OH-LXL courtesy AirHistory.net


Helsinki - Vantaa (EFHK / HEL)
2 March 2020; (c) Juhani Sipilä

Revision history:

Date/timeContributorUpdates
23-Jan-2013 13:26 harro Added

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