Robinson R22 N923SM accident near Panama City, Florida

Probable cause

The pilot's failure to properly remove and secure the tie-down ropes during the preflight inspection, which resulted in the ropes becoming entangled in the rotor head swashplate and pitch control rods during flight and the subsequent loss of pitch control.

NTSB analysis

The float-equipped helicopter was in cruise flight at an airspeed of 80 knots and an altitude of 800 ft mean sea level when it slowly started losing airspeed. The commercial pilot responded by pushing the cyclic control forward, but the airspeed continued to decrease, and the helicopter began to lose altitude. The pilot continued to push the cyclic forward until it contacted the control stop; he then realized that he had no cyclic control authority. The helicopter descended with no forward airspeed until it impacted the water. The helicopter floated briefly until waves struck its side and it rolled inverted. Postaccident examination of the helicopter revealed that the main rotor blades were deformed, the fuselage was substantially damaged, and the tail boom was partially separated. Further, the ropes used to tie down the helicopter’s main rotor blades were found wrapped around the rotor head swashplate and pitch control rods.

Before the flight, the pilot conducted a preflight inspection of the helicopter, which would have included removing the rotor blade tie-down ropes and associated socks that cover the rotor blade tips and storing them under the cockpit seat. However, because the ropes were found wrapped around the swashplate and pitch control rods, it is likely that the tie-down ropes were not properly removed and secured and, at some point during the flight, became entangled with the swashplate and pitch control rods, which prevented the pilot from being able to effectively control the pitch of the helicopter.

Text from the NTSB. Open the NTSB docket for ERA18LA140 for the full record.