Amateur-built 10 N396S accident near Morris, Illinois

Probable cause

The pilot’s failure obtain the proper rotor rpm before applying power for the takeoff roll which resulted in a loss of control.

NTSB analysis

The pilot taxied to the runway with the rotor still spinning from his previous landing, maintaining above a 100 rotor rpm on his gyroplane. As he taxied onto the runway, he noted his rotor rpm at 117 and he began to accelerate to build rotor speed, pitching back slightly. The pilot heard a loud pop and thinking he may have blown a tire on his right main landing gear, he glanced over to visually confirm it. He then checked his rotor rpm and found it had decreased to 80. At that same time, the gyroplane began to shake and then quickly turned over on its right side and came to rest on the left side of the runway, which resulted in substantial damage to the empennage and main rotor.

According to the manufacturer’s pilot operating handbook (POH), when taxiing the rotor is to be aligned with the gyroplane (stationary). The rotor pre-rotation procedure instructs the pilot to “increase engine power slowly until reaching 220 rotor rpm” and has a caution message that states, “CAUTION Start the take-off with the rotor between 150-200 rpm requires a high skill. It is forbidden to proceed with take-off operations if the rotor is under 150 rpm.”

It is likely that the pilot did not have sufficient rotor rpm to avoid rotor flap during the takeoff roll based on his statement. Whether the flat tire occurred during the takeoff or as a result of the gyroplane rolling over on its side was not determined.

Text from the NTSB. Open the NTSB docket for CEN26LA081 for the full record.