What happened
On 3 May 2018, an MBB-BK 117 D-2 EC145, registration G-RMAA, was operating as a Helicopter Emergency Medical Service (HEMS) in Wolverhampton, West Midlands. The aircraft had landed in a car park near Molineux Stadium to pick up a patient following a road traffic collision. After the patient was loaded and the engines were started, the pilot prepared for departure.
As the pilot increased the collective to transition into a low hover, the helicopter began to yaw toward the left. The pilot attempted to correct this movement by applying opposite anti-torque pedal, but the rotation continued. To prevent further loss of control, the pilot rapidly lowered the collective to land the aircraft. During this descent, the helicopter's fenestron protector struck a low perimeter wall, and the landing gear cross tube was deformed due to the force of the landing. There were no injuries to the crew or the three passengers on board.
The investigation
The AAIB examined the aircraft and reviewed flight data alongside bystander video footage. The investigation established that the aircraft's left anti-torque pedal was slightly depressed before liftoff and remained in that position while the skids were still in contact with the ground. As the aircraft became airborne, the yawing motion commenced.
Technical inspections by the operator's maintenance organization revealed no mechanical or technical failures that could have caused the loss of directional control. The investigation also looked into the pilot's experience, noting that while the commander had significant total flying hours, only 54 of those were on this specific aircraft type, with most previous experience being on the EC135 model.
Findings
- The pilot applied anti-torque pedal inputs that were appropriate for an EC135 but insufficient for the EC145.
- The helicopter's rotation was exacerbated by the pilot's pedal inputs being applied while the aircraft was still light on its skids.
- The landing site was found to be compliant with EASA regulations and the operator's procedures, though the investigation noted that the operator's internal guidance regarding aircraft dimensions needed updating.
Safety action
- The operator has re-briefed all pilots regarding the risks of remaining light on the skids during takeoff.
- The operator's Operations Department Communication has been updated to include the most recent EASA compliance references and to specify the dimensions for both the EC135 and EC145.