A pilot at Abu Dhabi's Etihad Airways passed out as the aircraft he was flying approached Abu Dhabi Airport, forcing an emergency landing.
The United Arab Emirates General Civil Aviation Authority is investigating the incident, which occurred on November 17 2012.
In a preliminary report, the authority said the pilot became incapacitated minutes before he was due to land the Airbus A320-232, which had flown from Kuwait with 70 passengers and six crew members on board.
The 44-year old Omani pilot was unable to speak properly and was having difficulty breathing before becoming unconscious.
The co-pilot declared an emergency and was forced to take over, successfully landing the plane without any injuries or damage, the report said.
Emergency services were on standby at the airport, while medical staff boarded the plane to assist the pilot, who regained consciousness soon after landing.
The pilot underwent a drug and alcohol test. The results will be included in the General Civil Aviation Authority’s final report.
Authorities will analyse the cockpit voice recorder and flight data recorder in their investigation.
A final report, including an assessment of how crew handled the incident and any safety recommendations, will be released later this year.