What happened
On 24 October 2007, a Sud SE.313B Alouette II, registration N577AG, was performing a private flight near Newbridge, Co. Kildare. The flight, which involved two pilots sharing handling duties, was attempting to land at a specific site in Castlewarden. After two unsuccessful approach attempts due to misjudged height and wind conditions, a third approach was initiated from a north-easterly direction.
As the helicopter attempted to establish a hover, the occupant in the right-hand seat applied aft cyclic, causing the aircraft to yaw left. Despite attempts to correct this using anti-torque pedals, the helicopter began a rapid rotation around its yaw axis, accompanied by intense vibrations. The aircraft' and main rotor blades struck trees along the eastern boundary of the landing site before impacting the ground with significant force. The impact caused substantial damage to the airframe, including the separation of the tail boom and tail rotor assembly.
The investigation
The AAIU examined the wreckage and the flight history of the crew. Technical analysis of the N577AG airframe revealed no pre-existing mechanical defects or manufacturing flaws in the rotor head, gearbox, or control systems that could have caused the loss of control. The investigation focused heavily on the regulatory status of the crew and their experience levels.
Investigators found that the right-seat occupant, the aircraft owner, was flying without a valid license for the Irish airspace, as his US Student Pilot License and medical certificate did not meet local requirements. While the left-seat occupant held a valid US Private Pilot License, he was not a qualified instructor and therefore lacked the legal authority to supervise the student pilot in that capacity. Furthermore, the left-seat occupant had very limited experience with this specific aircraft type, having flown it only once prior to the accident.