Enstrom F-28F accident near Palmer, Alaska, May 9, 2021
On May 9, 2021 at about 10:40 pm local time, a 1989 Enstrom F-28F (helicopter), registered N8627J, was substantially damaged in an accident during enroute near Palmer, Alaska. It was an other work-use flight under general aviation rules (Part 91). No one was hurt; 3 people were on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
A loss of drive to the rotor system due to the disengagement of the main belt drive tensioning system, which resulted in a forced landing. The disengagement was due to inadequate clearance between the clutch handle and the roll pin in the handle bellcrank when the handle was in the stowed position.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 9, 2021 · about 10:40 pm local time
- Place
- Palmer, Alaska · map
- Type
- Accident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Enstrom F-28F, built 1989 · all F-28Fs on the register
- Registration
- N8627J · no longer on the register · serial 760
- Damage
- Substantial damage
- Flight
- Other work-use flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
During a helicopter tour flight, the clutch disengage light dimly illuminated, flickered, then fully illuminated. As the pilot began to descend for landing, he felt the belt clutch disengage, and the engine rpm separated from the transmission rpm indicating the helicopter had lost engine power to the rotor system. The pilot entered an autorotation and made a forced landing in a nearby open field. The helicopter touched down with a tailwind of about 13 mph, slid forward and nosed down. 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, which resulted in substantial damage to the fuselage. A postaccident examination of the helicopter revealed that the main belt drive tensioning system (belt clutch) inadvertently disengaged in flight. Testing found that the disengagement occurred due to inadequate clearance between the clutch handle and the roll pin in the handle bellcrank when the handle was in the stowed position. As a result of this accident, the helicopter manufacturer issued a service bulletin that clarified the rigging requirements for the clutch handle and allowed for a minor modification to the handle to increase clearance between the handle and the roll pin in the bellcrank.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Powerplant sys/comp malf/fail during enroute defining event
The NTSB's findings
- Aircraft › Aircraft propeller/rotor › Main rotor drive › Engine/transmission coupling › Unintentional use/operation
Pilot
- Certificate: flight instructor, commercial pilot, private
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane single-engine; instructor: helicopter; instrument: airplane; rotorcraft: helicopter
- Flight time: 8,450 hours in all; 5,500 in this make and model; 40 in the last 90 days; 6 in the last 30 days; 8,400 as pilot in command; 1,345 on instruments
- Last flight review: November 5, 2020
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 4,650.7 hours
- Last inspection: annual inspection, September 1, 2020
- Maximum gross weight: 2,600 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming HIO-360-F1AD (piston); 0 hours total
- Operator: Talaheim Air Service LLC
The flight
- Departed from: Palmer AK at 10:45 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 140° at 13 knots, gusting 18
- Visibility: 10 statute miles
- Sky: overcast at 9,000 ft
- Temperature: 57°F (14°C), dew point 34°F (1°C)
- Altimeter: 30.10 inHg
- Observation at 2:53 pm from PAAQ, 2 miles away
Weather report (METAR): PAAQ 092253Z 14013G18KT 10SM OVC090 14/01 A3010 RMK AO2 SLP193 T01440006
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flig | 1 | |||
| Passengers | 2 |
Other NTSB records under N8627J the same tail number, which may have belonged to a different aircraft at the time
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number ANC21LA038.