An off-duty pilot stepped in to help land a plane being diverted to Dublin Airport after a co-pilot fell ill.
The officer had been travelling as a passenger on a Lufthansa 747 flying from Newark to Frankfurt on Monday morning when it is understood the crew member suffered a severe migraine and was incapacitated.
Flight LH403 landed safely in Dublin at about 5.30am, Dublin Airport Authority (DAA) confirmed.
A Lufthansa spokeswoman said the man who stepped in was fully licensed to operate and fly the 747.
"In such circumstances it's absolutely normal procedure for the pilot, the flight captain, to continue to operate the aircraft," she said.
"Also, where necessary, the cabin crew are fully trained and can be called upon to read checklists back to the pilot. The procedures are in place for such an eventuality. But the effort of the off-duty pilot were certainly appreciated."
The Irish Aviation Authority () has been notified of the incident and has received a briefing report. The Air Accident Investigation Unit (AAIU) of Ireland's Department of Transport has been notified and is investigating.
Experts from the AAIU attended the plane after it touched down in Dublin.
"Whenever you have any sort of medical issue on board, whether it's a doctor or appropriately qualified person, that's always appreciated. The flight would have been operated as per procedures and safely even if the off-duty pilot had not been there," the Lufthansa spokeswoman added.
An announcement was made on the flight by crew members seeking medical assistance after the officer fell ill. It is understood there were several doctors or medically qualified people on board.