Bell 47G N684PC accident near Gaston, Oregon

Probable cause

The pilot's inability to maintain control of the helicopter as a result of a hydraulic hose becoming entangled around the right skid.

NTSB analysis

The pilot stated that the purpose of the flight was to perform a mosquito abatement aerial application. With the helicopter parked adjacent to the pond where the application was to occur, the helicopter ground crew installed a bucket and related dispersement equipment. They attached the hydraulic lines and straps, which were designed to connect in such a manner that they could be disconnected by the pilot in an emergency situation. The ground crew and pilot verified that the emergency features functioned properly and adjusted the hydraulic pressure. The bucket, located about two feet in front of the helicopter, was filled and the ground crew cleared the pilot for takeoff.

The pilot raised the collective control and set his focus on a mirror affixed to the left skid in an effort to assess the bucket's height. As the helicopter lifted off, it lurched forward and, in response, the pilot applied aft cyclic. Despite the pilot's attempts, the helicopter continued to uncontrollably move forward and then assumed a nose-down attitude. The helicopter collided with terrain and rolled onto the left side substantially damaging the fuselage. Upon egressing the helicopter, the lead crew member showed the pilot that the hydraulic line was tangled around the right skid. The other crew members said that they observed the hose on the skid during taking off but, due to their vantage point, were unable to signal the pilot.

The pilot stated that the accident could have been prevented if he had raised the collective slower. He further added that there were no pre impact mechanical malfunctions or failures that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR14CA280 for the full record.