Clutch Disengage Light Dimly Illuminated, Flickered, And Then Fully Illuminated

Location: Palmer, AK Accident Number: ANC21LA038
Date & Time: May 9, 2021, 14:40 Local Registration: N8627J
Aircraft: Enstrom F-28F Injuries: 3 None
Flight Conducted Under: Part 91: General aviation – Other work use

On May 9, 2021, about 1440 Alaska daylight time, an Enstrom F-28F, N8627J, sustained substantial damage when it was involved in an accident near Palmer, Alaska. The pilot and two passengers were not injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 sightseeing tour flight.

The pilot reported that at about 1330 he took over as the pilot for Talahiem Air Service, who was providing helicopter tour flights for the Great Alaska Aviation Gathering that was taking place at the fairgrounds in Palmer. The pilot had fueled the helicopter with 25 gallons of fuel, performed a normal start-up, and he then engaged the belt clutch before the passengers for the flights were escorted to the helicopter. The tour flight was conducted around the local area, for about 15 minutes, terminating back at the fairgrounds. The pilot added that, during the accident flight, while returning to the fairgrounds, the clutch disengage light dimly illuminated, flickered, and then fully illuminated. He reported that there was “no vibration and nothing to indicate that there was any problem”, but he prepared for a sudden belt clutch release. As the pilot started to descend for the approach into the fairgrounds, he felt the belt clutch disengage and the engine RPM separated from the transmission RPM, and the helicopter lost engine power to the main rotor system.

The pilot estimated that the helicopter was at about 200 feet AGL and an airspeed of about 80 MPH when he reduced the throttle, bottomed the collective, and entered an autorotation. The approach and flair were normal as he lined up for an open field with about a 13 MPH tailwind. The helicopter touched down with about 15 MPH of ground speed, and the pilot believed the main rotor RPM was low. During the emergency off-airport landing, the helicopter landed on unstable terrain and slid. Subsequently, the nose of the helicopter descended onto the ground, a main rotor blade impacted the ground in front of the helicopter followed by a main rotor blade impacting the tail section just forward of the stabilizers. The tail boom became partially displaced from the fuselage, and the fuselage, main rotor blades, and tail rotor blades sustained substantial damage. The pilot and two passengers were able to exit the helicopter with no further incident.

The pilot added that at the beginning of the flight, the belt engagement felt normal, the clutch snapped into over-center, and the clutch engagement light went out.

The helicopter was equipped with a Lycoming HIO-360 engine. The helicopter has been recovered and a detailed examination is pending.

FMI: www.ntsb.gov