Helicopter Incident in Mannheim Involving an EC135 P2+

Incident Overview and Aircraft Details On August 23, 2007, a Eurocopter EC135 P2+ (manufactured in 2007, serial number 0572) was involved in a serious incident at the Mannheim-City airfield. The aircraft, powered by two Pratt & Whitney 206 B2 engines, was being prepared for a primary emergency medical response. The pilot, a 58-year-old with 7,736 total flight hours, was operating the helicopter from a mobile transport platform. ## Sequence of Events At 10:36 local time, the crew was alerted for a primary mission. The pilot and rescue assistant boarded the helicopter, which was connected to an external power supply. The emergency physician, standing outside, monitored the engine start and removed the external power plug upon the pilot's signal. He then placed the plug on the ground in front of the platform and boarded the aircraft. During the takeoff, the pilot brought the helicopter into a hover over the platform and pitched forward to gain speed. Suddenly, the helicopter entered a steep nose-down attitude, reaching up to 80 degrees, with the rotor tips approximately 1 meter from the ground. The mobile platform was dragged forward by the helicopter. The aircraft then rolled to the right and yawed 180 degrees. During this maneuver, the external power cable, which was caught between the cross traverse and the right skid, detached. The pilot subsequently landed the helicopter in a controlled manner. ## Contributing Factors and Investigation Findings The investigation determined that the serious incident was caused by a loop of the external power cable around the right skid tip. When the helicopter accelerated, the cable became taut, pulling the aircraft into an uncontrolled attitude. The mobile platform was dragged because the cable did not yield, and a designated break point near the voltage converter was ineffective due to the cable being jammed against the skid. The incident was exacerbated by the time pressure associated with emergency medical starts, which typically require a 120-second response time. The external power connection procedure was originally designed for the BK117 helicopter, which had a front-mounted power socket. The EC135, used as a temporary replacement since July 5, 2007, had a rear-right power socket, requiring the cable to be routed around the helicopter and over the right skid. The pilot could not see the right skid or the cable with the door closed. The black color of both the skid and the cable may have contributed to the loop going unnoticed. ## Safety Recommendations and Context The report noted that no specific regulations existed for the design or use of mobile helicopter transport platforms. Previous incidents involving such platforms were cited, including a 1996 collision with a hangar and a 2005 incident where a helicopter caught on a wheel. The report highlighted the need for updated procedures to accommodate different helicopter models and the importance of clear visual cues for external equipment.