A British Airways Airbus A320-200, registration G-GATL performing flight BA-2676 from London Gatwick,EN (UK) to Paphos (Cyprus), was descending through 8000 feet to 6000 feet towards Paphos when the first officer noticed an unusual odour in the cockpit and queried the captain whether he would also smell onion bahjis, the captain indicated he did not. About 30 seconds later the first officer felt his arms and legs were tingling and he had the impression he was about to faint. He donned his oxygen masks and made sure oxygen was set to 100%. He then turned to the captain telling him, he didn't feel good, but there was no response, the first officer then indicated he was incapacitated, still no response from the captain. After a couple of seconds the captain finally reacted stating very slowly he didn't feel good, too, and donned his oxygen mask. Both pilots verified the captain's oxygen was set to 100%. During that time several calls by ATC to descend to 4000 feet went unnoticed. The pilots recovered a bit, however, could not establish two way communication between them with the oxygen masks on, they figured the captain could hear the first officer but the first officer could not hear the captain. The captain was pilot flying and began to point to the checklist to be executed (smoke, fire, fumes), then throughout the approach pointed to the relevant levers to be operated for flaps and gear extension while the first officer continued to communicate with ATC and read the checklists. The aircraft landed safely on Paphos' runway 29 about 13 minutes after the onset of trouble, the crew opened the cockpit windows immediately after roll out before taxiing to the stand.
Following shut down at the stand the captain went to the lavatory almost immediately, while the first officer checked with the cabin whether there was everything okay. The cabin had not noticed anything untoward, however, the flight attendant was shocked by the view of the first officer being completely pale. She stated there was a strong smell of fuel from the cockpit when the cockpit door opened. The tingling, confusion and difficulties to concentrate continued past the landing despite the oxygen mask. Both pilots went to a hospital where they were both diagnosed with very low blood oxygen saturation and feaver. The doctors recommended the flight crew to stay in hospital overnight for monitoring, however, the pilots preferred to go to the hotel and returned to London the next day as passengers, refusing to fly on the occurrence aircraft.
The occurrence aircraft remained on the ground for about 27 hours, then returned to London Gatwick as flight BA-2675 and continued service.