On 17 November 2017, an Airbus A320 flight crew were both partially incapacitated by the effect of fumes described as acrid and stinging which they detected when following another smaller aircraft to the holding point at Geneva and then waiting in line behind it before taking off, the effect of which rapidly worsened en-route and necessitated a precautionary diversion to Marseilles. The very thorough subsequent Investigation was unable to determine the origin or nature of the fumes encountered but circumstantial evidence pointed tentatively towards ingestion of engine exhaust from the aircraft ahead in one or both A320 engines.