A passenger was knocked unconscious and a pilot inadvertently set off an emergency warning when an aircraft hit severe turbulence approaching Donegal Airport, according to an air accident report published yesterday.
The incident happened last December as the Aer Arann aircraft, with 32 passengers and three crew on board, completed the flight from Dublin in bright, clear weather.
Several passengers and a crew member were injured. Both pilots struck their heads off the cockpit ceiling. All the passengers were "traumatised" by the incident, which happened because of the flight path taken on approach to the airport, according to the report of the Air Accident Investigation Unit (AAIU) of the Department of Transport.
In an interview with the AAIU, the captain of the ATR 42-300 aircraft said the turbulence struck without warning as the aircraft descended in benign weather at 1p.m. on December 2nd.
During the turbulence, which lasted for up to 10 seconds, the first officer's hand inadvertently hit switches in an overhead panel, causing all the cockpit lights to illuminate.
This indicated a "catastrophic failure", which was not the case, but "such an indication could have led to actions which could have had very serious consequences", the captain told investigators.
The cabin attendant said she was about to reverse from the cockpit area with glasses in her hand when she was suddenly thrown backwards. She struck the top of the cockpit doorframe with her legs and fell to the floor.
She was then in the small baggage area between the cockpit and the cabin, and used the baggage netting to haul herself to her feet. She then opened the cabin door to check on the passengers, and reported to the captain that one required medical attention.
This passenger, who was later hospitalised with arm, shoulder and back injuries and a suspected fracture of the humerus, said the aircraft suddenly dipped to port and then banked to starboard. There was a terrible noise coming from up front and he lost consciousness. When he regained consciousness his left leg hurt. Other passengers received minor injuries.
The AAIU said the aircraft was flown through an area in the lee of Mount Errigal where the transverse wind generated a condition of severe turbulence.
"The flight crew failed to appreciate the possible effect of a transverse wind when flying in the lee area of a significant conical-shaped mountain," its report said.
It recommended that the Irish Aviation Authority should review the procedure in the instrument approach chart taking aircraft over Mount Errigal and the adjacent mountain range. It said the IAA should consider a turbulence warning for Donegal Airport in its aeronautical information publication.
The investigation team contacted the aircraft manufacturer about the possibility of mounting a guard over the switch inadvertently struck by the first officer. The manufacturer said, however, that the switch had enough protection from unintentional selection.
