A Swiss International Air Lines Boeing 777-300ER, registered HB-JNF, declared a mayday while flying over the Atlantic Ocean on 24 August 2026. The aircraft was operating flight LX9 from Chicago O’Hare to Zurich with 222 passengers on board.
About halfway across the Atlantic, the crew detected a pungent odour in the economy class cabin but were unable to identify its source. As a precaution, the pilots elected to divert to Lajes Airport on the Azores island of Terceira and declared an in-flight emergency.
The Boeing 777-300ER landed safely at approximately 06:30 local time. Lajes Airport, which serves both military and civilian operations, remained fully operational as the aircraft exited the runway under its own power and taxied to the apron.
All passengers disembarked safely. Following the landing, five passengers and one crew member underwent precautionary medical evaluations after briefly experiencing symptoms including eye irritation, nausea and headaches. Swiss confirmed that no further medical treatment was required, while the cause of the odour remains under investigation
