Robinson Helicopter R44 accident near Fort Glenn, Alaska, September 19, 2015
On September 19, 2015 at about 1:00 am local time, a 1999 Robinson Helicopter R44, registered N7162R, was substantially damaged in an accident during maneuvering (hover) near Fort Glenn, Alaska. It was an other work-use flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The separation of the tail rotor gearbox from the tailboom attachment point due to overstress loads imposed by a tail rotor blade imbalance as the result of impact with an undetermined object during low-level flight operations.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 19, 2015 · about 1:00 am local time
- Place
- Fort Glenn, Alaska · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson Helicopter R44, built 1999 · all R44s on the register
- Registration
- N7162R · registry record · serial 0670
- Damage
- Substantial damage
- Flight
- Other work-use flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The commercial helicopter pilot was conducting an aerial mustering flight with cattle on a remote island. The pilot reported that, while in a hover, he heard "metallic grinding noises" from behind his position in the front right seat; however, the helicopter was "stable with engine power," the rotor rpm was within normal limitations, and the had "normal responding controls and tail rotor authority." The pilot immediately landed the helicopter on a sandbar, completed the shutdown process, and exited from the helicopter without further incident. While conducting a postflight inspection, the pilot observed that the tail rotor gearbox had separated from the tailboom mounting assembly and was lying on the ground. An examination of the tail rotor gearbox mounting flange bolts and the tail rotor blades revealed signatures consistent with overstress. No signatures of pre-existing damage were observed during the examination. During the low-level profile flown during the aerial mustering operation, it is likely that the tail rotor blades impacted an object which resulted in a severe imbalance of the blades and subsequent separation of the tail rotor gearbox. During the impact and separation sequence, the tail rotor blades likely impacted the vertical stabilizer where the red tail rotor blade "danger" decal is mounted. An examination of the components could not determine what object was impacted. No evidence of impact with foreign objects such as birds, vegetation, or cattle was observed, although such an impact could not entirely be ruled out since neither of the tail rotor blade tips was recovered.
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
- Low altitude operation/event during maneuvering (low-alt flying)
- Collision with terrain or object (not controlled flight into terrain) during maneuvering (hover)
- Unknown or undetermined during maneuvering (hover)
- Part(s) separation from AC during maneuvering (hover) defining event
- Off-field or emergency landing during maneuvering (hover)
The NTSB's findings
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
- cause Environmental issues › Physical environment › Object/animal/substance › (general) › Effect on equipment
- cause Aircraft › Aircraft propeller/rotor › Tail rotor › Tail rotor blade › Damaged/degraded
- cause Aircraft › Aircraft propeller/rotor › Tail rotor drive system › Tail rotor gearbox › Damaged/degraded
Pilot
- Certificate: commercial pilot
- Ratings: instructor: helicopter; rotorcraft: helicopter
- Flight time: 3,278 hours in all; 3,278 in this make and model; 3,150 as pilot in command
- Last flight review: February 12, 2015
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 2,490.5 hours
- Last inspection: 100-hour inspection, July 21, 2015
- Maximum gross weight: 2,400 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-540-F1B5 (piston); 1,098 hours total
- Operator: Bering Pacific Ranches, Ltd.
The flight
- Departed from: Fort Glenn AK
- Destination: Fort Glenn AK
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 310° at 16 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 3,600 ft; scat at 2,600 ft
- Temperature: 48°F (9°C), dew point 37°F (3°C)
- Altimeter: 29.94 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N7162R the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.