Robinson Helicopter Company R44 II accident near Lake Sutherlin, Montana, July 25, 2017
On July 25, 2017 at about 1:30 am local time, a 2004 Robinson Helicopter Company R44 II, registered N233JD, was substantially damaged in an accident during maneuvering (low-alt flying) near Lake Sutherlin, Montana. It was a personal flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot’s transition into an out-of-ground-effect hover in high-density altitude conditions that exceeded the helicopter’s performance capabilities, which resulted in loss of rotor rpm.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 25, 2017 · about 1:30 am local time
- Place
- Lake Sutherlin, Montana · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Robinson Helicopter Company R44 II, built 2004
- Registration
- N233JD · registry record · serial 10300
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The airline transport pilot was conducting a cross-country, personal helicopter flight. He reported that, while looking for a place to camp, he initially landed in one area; however, he decided it was unsuitable and lifted off, at which time he noticed the rotor rpm was low. He then twisted the throttle to full, and the rotor rpm immediately increased. The pilot then proceeded across a small ravine toward a hill traveling about 10 to 20 knots and about 25 ft above ground level. The low rotor warning horn sounded, and the engine began to lose power. The pilot added that, because he had already set the throttle to full power, he decided his only option was to lower the collective and fly downhill to gain airspeed and regain rotor rpm. The pilot leveled the helicopter just above the water's surface and increased the collective to cushion the landing. As the helicopter settled into the water, it rolled over onto its left side and then became partially submerged. Examination of the engine did not reveal evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation. Given the reported gross weight of the helicopter, accident site elevation, and temperature, the helicopter was operating at the upper limit of its performance capabilities. Performance charts indicated that the helicopter would not have been able to hover out of ground effect at that elevation; therefore, it is likely that, when the helicopter crossed the ravine and entered an out-of-ground-effect hover, there was insufficient available power to sustain the out-of-ground-effect hover due to the throttle already being positioned to full power, which resulted in the loss of rotor rpm.
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
- Loss of engine power (total) during maneuvering (low-alt flying) defining event
- Off-field or emergency landing during maneuvering (low-alt flying)
- Roll over during landing
The NTSB's findings
- cause Aircraft › Aircraft oper/perf/capability › Aircraft capability › Climb capability › Capability exceeded
- cause Personnel issues › Task performance › Use of equip/info › Use of equip/system › Pilot
- cause Environmental issues › Conditions/weather/phenomena › Temp/humidity/pressure › High density altitude › Effect on operation
- Aircraft › Aircraft oper/perf/capability › Aircraft capability › Maximum weight › Not specified
Pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane; rotorcraft: helicopter
- Flight time: 6,295 hours in all; 730 in this make and model; 87 in the last 90 days; 22.5 in the last 30 days; 5,500 as pilot in command; 25 on instruments
- Last flight review: June 15, 2017
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 53 hours
- Last inspection: annual inspection, July 6, 2017; 10 hours since
- Maximum gross weight: 2,500 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming IO-540-AE1A5 (piston); 70 hours total
The flight
- Departed from: White Sulphur S MT at 1:15 am
- Destination: Lake Sutherlin MT
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 300° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 88°F (31°C), dew point 36°F (2°C)
- Altimeter: 29.87 inHg
- Observation at 1:53 am from KHLN, 51 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
8 documents, released by the NTSB on January 15, 2020. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Engine Data Monitor Factual Report | PDF, 2 pages | View Download |
| 2 | Engine Data Monitor Factual Report - Attachment 1 | data file | Download |
| 3 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 4 | Wreckage Examination Notes | PDF, 1 page | View Download |
| 5 | Robinson R44 Performance Charts | PDF, 3 pages | View Download |
| 6 | Fuel Servo Examination | PDF, 8 pages | View Download |
| 7 | Evidence Control Forms | PDF, 2 pages | View Download |
| 8 | Statement of Party Representatives to NTSB Investigation - Robinson Helicopter | PDF, 1 page | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Other NTSB records under N233JD 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.