Incident Overview
A helicopter pilot reported that after landing and dropping off the crew chief, he planned to reposition to another company landing zone. He opened the engine cowling to allow the engine to cool before restart. However, the pilot did not perform a thorough preflight walk-around and subsequently climbed into the cockpit and departed.
Sequence of Events
Approximately sixty seconds after takeoff, the pilot felt a large thump throughout the airframe and landed as soon as practicable. Upon shutdown and inspection, he discovered that the engine cowling had separated from the helicopter. The cowling struck the right two main rotor blades and the vertical stabilizer, resulting in substantial damage to both components.
Pilot Report
The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
Company Policy Recommendation
In the recommendations section of the National Transportation Safety Board Pilot Aircraft Accident Report, the pilot specified that the company has since issued a policy that prohibits opening the engine cowling for the sole purpose of allowing the engine to cool. Additionally, the policy now requires a pre-takeoff helicopter inspection to be completed by a qualified technician.