SAS B736 near Copenhagen on Feb 5th 2014, first officer incapacitated

A SAS Scandinavian Airlines Boeing 737-600, registration LN-RPY performing flight SK-579 from Stockholm (Sweden) to Paris Charles de Gaulle (France), was enroute at FL400 about 30nm north of Copenhagen (Denmark) when the first officer, pilot flying, indicated he felt unwell, dizzy, nauseous and about to vomit. The captain took control of the aircraft and relieved the first officer from duty. The first officer left the cockpit to visit the toilet, however, needed to sit down in a cabin crew seat at the forward galley. A flight attendant, trained nurse, assisted the first officer, whose dizziness increased. The first officer was instructed to lay down on the galley floor, the captain was informed the first officer would not be able to return to the cockpit. The captain therefore initiated the diversion to Copenhagen. Two medical doctors amongst the passengers came to the galley to assist the first officer, oxygen was provided. By instruction of the captain a member of the cabin crew took the first officer's seat in order to assist with radio communication. The aircraft landed safely in Copenhagen about 30 minutes after the first officer began to feel unwell, there was no improvement in the first officer's status until after landing. The first officer was taken to a hospital.

Denmark's Havarikommission (HCL) released their final report concluding the probable cause of the serious incident was:

A virus related infection was the most probable cause of the incapacitation of the first officer.

Additional findings:

- The risk of other crew members becoming incapacitated was almost non-existing since no indication of food poisoning was revealed.

- The crew’s adherence to the operator’s procedures mitigated potential negative safety effects.

- At no point during the sequence of events, did the incapacitation endanger the safety of the passengers and the aircraft.

The HCL reported this diversion occured on the third consecutive day of flihgt duties, the captain and first officer had been rostered to fly together during all of these 3 days. After feeling unwell the first officer did not throw up. He was examined in hospital, however without any diagnosis, and was released at about midnight (about 7:45 hours after landing). The first officer returned home and consulted a medical specialist who diagnosed the illness as virus related.

The HCL analysed: "This is the single most important issue in regard to the safety of the flight, as the remaining cockpit crew member, i.e. the commander, most likely would not be subjected to a similar incapacitation. It was not possible to determine when the first officer was exposed to source of the virus infection. However, the Danish AIB assumes that it might have happened before the start of the three day duty period."