Bell 222 N222LL accident near Milliken, Colorado

Probable cause

The separation of the left engine cowling for undetermined reasons.

NTSB analysis

A witness on the ground was watching the helicopter when he saw several pieces fall off and subsequently land in his and a neighbor's yard. The commercial pilot said that he was en route cruising at approximately 1,500 feet above ground level when he felt a "bump on the controls" and heard a "bang" and thought that he had hit a bird. He returned to his departure airport 45 miles away for an otherwise uneventful landing. On postflight inspection, the pilot discovered that the lower portion of the left engine cowling was missing and that the cowling pieces had struck both main rotor blades and both tail rotor blades, but no evidence of bird remains were found. The impact caused substantial damage to the left engine cowling, both tail rotor blades, the tail rotor yoke, and the tail rotor gearbox. The pilot and his passenger were not injured. The pilot said that before departure he had conducted a preflight inspection; however, the Federal Aviation Administration inspector who examined the helicopter and the separated pieces of the left engine cowling found no evidence of bird remains and no damage to the cowling latches that would have prevented them from operating normally prior to the accident.

Text from the NTSB. Open the NTSB docket for CEN09CA218 for the full record.