Event Details

Title:Contaminated air, Incident onboard aircraft SE-DRE during flight between Stockholm and Malmö, M county, Sweden, on 12 November 1999
Micro summary:Contaminated air causes distinct physiological symptoms for the crew of this BAE-146.
Event Time:1999-11-12 at 1800 UTC
File Name:1999-11-12-SE.pdf
Publishing Agency:Swedish Accident Investigation Board (AIB)
Publishing Country:Sweden
Report number:RL 2001:41e
Site of event:Muliple occurrences on multi-leg trip.
Departure:Stockholm-Arlanda Airport, Marsta, Sweden
Destination:Malmö/Sturup Airport, Sweden
Airplane Type(s):BAe 146-200
Flight Phase:Cruise
Operator(s):Braathens Malmö Aviation AB
Type of flight:Revenue
Serious Injuries:0
Other Injuries:0
Executive Summary:The crew was to carry out three return flights between Stockholm and Malmö together. The flying time on the route is approximately one hour. During the first flight the purser experienced an unpleasant feeling of fainting. She told the other two cabin crewmembers about this and they stated that they had also experienced something similar. They did not recognize any special odour. The pilots had not noticed anything abnormal.

During the subsequent flight one of the cabin attendants who was placed in the forward part of the cabin, experienced an odd pressure in the head, nasal itching and ear pain. The other two colleagues in the cabin also felt discomfort and the feeling of “moon walk” while working. The pilots, who did not notice anything abnormal during the second flight either, discussed whether the problem could possibly be due to some fault within the cabin pressure system.

The third flight that same day was flown by the commander. During the flight, which took place at a cruising altitude of FL 280, all three members of the cabin crew experienced similar discomfort as during the preceding two flights, but more pronounced. During the first portion of the flight the pilots did not notice anything abnormal but shortly before they were to leave the cruising altitude the commander began to feel a mild dizziness.

During the approach towards Malmö/Sturup airport when the aircraft was descending through FL 150 the co-pilot suddenly became nauseous and donned his oxygen mask. Then, after an estimated period of ten seconds, the commander also became very nauseous and immediately donned his oxygen mask. After a few seconds of breathing in the oxygen mask the co-pilot felt better and thereafter had no difficulty in performing his duties.

However, the captain felt markedly dizzy and groggy for a couple of minutes. He had difficulty with physiological motor response, simultaneity and in focusing. Finally he handed over the controls to the co-pilot. After having breathed oxygen a few minutes even the captain began to feel better and thereafter the pilots were able to accomplish a normal approach and landing on runway 17 without problems. Subsequent to the incident, the airline performed a trouble-shooting of the aircraft, which ascertained a minor external oil leak on engine # 2. An extensive technical investigation has been performed on the aircraft and on engine # 2. During engine test in test cell and flight test airspecimens from the bleed air- and the air-condition system and have been taken and analyzed. The samples have not provided any indication of what/which chemical substances caused the symptoms and no technical fault that can explain the incident has been found.

The Board calls the attention to the fact that the location of the customer bleed port for the air-conditioning system is not optimal on the engine type and that knowledge is lacking concerning modern lubrication oils’ characteristics at very high pressure and temperatures and their effect on human health. In addition instructions were lacking concerning how crews shall act during flight when suspicion arises about contaminated cabin air.

The incident was caused by the pilots becoming temporarily affected by
probably polluted cabin air.
Learning Keywords:Operations - Cabin or Cockpit Smoke
Operations - Pilot incapacitation
Close match:Pilot incapacitation, BAe 146-300, G-JEBA, February 2, 2006
Noxious fumes, Boeing 757-236, G-CPET, March 10, 2006


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