NTSB Identification: CHI08LA211
14 CFR Part 137: Agricultural
Accident occurred Thursday, July 24, 2008 in Mayville, WI
Probable Cause Approval Date: 09/30/2009
Aircraft: BELL 47G-4A, registration: N24HM
Injuries: 1 Fatal.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

A witness heard the engine running rough when the agricultural application helicopter took off, adjacent to the field that was going to be sprayed. The pilot then landed the helicopter in the field which had tall vegetation and uneven terrain. The left skid separated during landing resulting in the helicopter resting left side low. The pilot then exited and walked around the helicopter when he was struck by the rotating main rotor blades and was fatally injuried. Examination of the engine revealed an exhaust valve that displayed excessive wear which would result in the engine running rough due to the valve sticking. Logbook records show that the engine and parts manufacturer approval (PMA) manufacturer's recommended maintenance had not been performed.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot's failure to maintain clearance with the rotating rotor blades after he exited the helicopter after landing.

Full narrative available

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