What happened
On 27 May 2008, an Airbus A319-132, registration D-AGWK, was performing a scheduled flight from Dublin to Cologne. During the climb, the aircraft passed 10,000 feet when the Purser notified the cockpit that several passengers appeared to have fallen asleep and a cabin crew member seemed unresponsive. The Captain, experiencing a tingling sensation in his arm, and the flight crew subsequently decided to don oxygen masks.
After declaring an emergency, the crew initiated an immediate descent and returned to Dublin. Upon landing, the aircraft was held at a remote stand, and emergency services were deployed. While some passengers reported feeling drowsy, no injuries were sustained by the 119 passengers or the 6 crew members on board.
The investigation
The AAIU conducted a thorough investigation, which included air composition checks at Dublin Airport and extensive technical testing at the manufacturer's facility in Toulouse. Investigators examined the aircraft's air conditioning systems, engine and APU oil, and cabin air recirculation filters.
Testing in Toulouse revealed trace amounts of substances such as Toluene, Ethybenzene, and Styrene. These were found in concentrations far below any hazardous exposure limits. The investigation also noted that the presence of these substances was likely due to the induction of exhaust gases while the aircraft was on the ground.
Findings
- The flight crew and passengers experienced symptoms of malaise and drowsiness, which resolved once oxygen masks were donned.
- Extensive technical inspections of the Airbus A319-132 revealed no mechanical defects or failures in the pressurization or air supply systems.
- The induction of exhaust gases while the aircraft was on the ground was identified as the probable cause for the presence of trace volatile organic compounds.
- Air quality tests showed carbon monoxide and carbon dioxide levels were well within safe, permissible limits.