What happened
On 9 July 2009, a Robinson R44 Clipper, registration G-DBUG, was performing a private flight at Welshpool Airport in Powys. After completing standard start-up procedures, which included a momentary test of the hydraulic system, the pilot lifted the aircraft into a hover. The intention was to taxi from the north apron toward the fuel bay, passing an air ambulance.
During the maneuver, the pilot experienced sudden heaviness in the cyclic control and felt the aircraft become laterally unstable, causing it to drift toward the parked air ambulance. In an attempt to avoid a collision, the pilot applied forward cyclic and raised the collective, ultimately deciding to execute a run-on landing. However, the pilot could not maintain a sufficient nose-up attitude, resulting in the helicopter striking the ground in a nose-down position and rolling onto its right side. There were no injuries to the pilot or the passenger.
The investigation
Investigators examined the aircraft's hydraulic system, including a visual inspection, an operational check of the hydraulic pump, and a test using a slave hydraulic pump driven by an electric motor. The inspection found no mechanical defects that would account for the reported control difficulties.
An instructor arriving at the scene noted that the hydraulic switch was in the 'off' position. The investigation focused on the pilot's recent transition from a Robinson R22, a smaller aircraft without hydraulic controls. It was noted that the hydraulic switch on the R44 is located on the front of the cyclic stick, in a nearly identical position to the Press-To-Talk (PTT) switch found on the R22.