What happened
On 17 November 2017, a Vueling Airlines Airbus A320-214, registration EC-HQJ, was operating a commercial flight from Geneva-Cointrin to Barcelona. During taxiing and while holding at runway 05, the aircraft was positioned behind a Cessna Citation Excel. The flight crew reported a strong, acrid, and acidic odor of exhaust gases entering the cockpit.
Shortly after takeoff and during the initial climb, the flight crew began experiencing physical symptoms. The captain reported feeling nauseous and dizzy, while the first officer also felt unwell and intoxicated. To mitigate the effects, the crew increased the air intake and eventually deployed oxygen masks. The captain requested the purser to monitor the cockpit and instructed the crew to keep the cockpit door open.
As the symptoms persisted, the crew decided to divert to Marseille-Provence airport. The flight was conducted using autopilot, and the crew continued to wear oxygen masks throughout the descent. The aircraft landed safely at 0-9:36 UTC. Upon arrival, the crew were transported to a hospital for evaluation. While blood tests showed no signs of carbon monoxide poisoning, the pilots continued to suffer from intermittent nausea and dizziness for several days.
The investigation
The BEA examined several hypotheses regarding the source of the contamination. Investigators reviewed maintenance records for both the Airbus A320-214 and the preceding Cessna Citation. No technical anomalies or leaks were found in the engines, APU, or hydraulic systems of the Vueling aircraft.
To investigate potential chemical exposure, the BEA analyzed various aircraft components, including avionic and air conditioning filters, as well as cockpit seat parts, searching for traces of organophosphates (TCP/ToCP). Additionally, the BEA performed advanced toxicological analysis on hair samples taken from the flight and cabin crew to detect lipophilic substances that might have been absorbed during the flight. The results of these analyses were negative for significant levels of known contaminants.
Findings
- The flight crew experienced partial incapacitation due to physical symptoms including nausea and dizziness.
- The presence of the Cessna Citation at the holding point for several minutes created conditions conducive to the concentration of exhaust gases in front of the Airbus.
- The ingestion of exhaust gases from the preceding aircraft is the most likely cause, as the timing of the odors coincided with the onset of symptoms.
- While the acrid smell was consistent with nitrogen and sulfur oxides, the specific toxic agent remains unidentified, as the symptoms disappeared or the substance was not captured in subsequent testing.