What happened
On 23 November 2010, a private Robinson R44 II helicopter, registration EI-WWI, was attempting to lift off from a concrete surface near Baltinglass, Co Wicklow. During the initial ascent, the aircraft experienced a sudden and sharp yaw to the left. The pilot, unable to stabilize the rotation, attempted to land the aircraft immediately to regain control. During this emergency landing, the tail-rotor guard struck the ground with significant force, causing the tail-rotor blades to fracture and the entire empennage and tail-rotor gearbox to separate from the tail-boom. The aircraft came to rest on a grassy area, and the pilot was able to shut down the engine and exit the wreckage without injury.
The investigation
AAIU investigators examined the wreckage at the site and analyzed the tail-rotor gearbox, which was sent to the Robinson Helicopter Company in the USA for technical disassembly. The investigation confirmed that the aircraft had recently undergone an annual inspection and was airworthy at the time of the accident. Physical evidence at the scene, including rotational skid marks on the concrete and indentations in the grass, supported the sequence of a sudden rotation followed by a heavy impact. The examination of the tail-rotor blades revealed damage consistent with a strike against the tail-rotor guard, which was painted with red and white stripes.
Findings
- The aircraft was properly maintained with a valid Certificate of Airworthiness.
- Weather conditions were clear and sunny with light winds, posing no contribution to the event.
- Excessive application of left pedal at lift-off caused the initial uncontrolled yaw.
- The pilot's attempt to land the aircraft quickly resulted in the tail-rotor guard striking the ground.
- The resulting overload forces from the tail-rotor strike caused the separation of the gearbox and empennage from the tail-boom.
- A lack of recent flying currency was noted, as the pilot had only one flight in the five months preceding the accident.