Enstrom F-28A accident near Mountain Home, Idaho, July 28, 2021
On July 28, 2021 at about 5:30 pm local time, a 1974 Enstrom F-28A (helicopter), registered N46MU, was substantially damaged in an accident during maneuvering (hover) near Mountain Home, Idaho (Mountain Home Municipal Airpor airport). It was a personal 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 pilot's improper fuel planning and improper in-flight decision-making, which resulted in a total loss of engine power due to fuel exhaustion and a subsequent hard landing on uneven terrain.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 28, 2021 · about 5:30 pm local time · cases in 2021
- Place
- Mountain Home, Idaho · Mountain Home Municipal Airpor · cases near this airport · map
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Enstrom F-28A, built 1974 · all F-28As on the register
- Registration
- N46MU · registry record · serial 253
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that, while the helicopter was in the hanger, he put 4 gallons of fuel into the left fuel tank. He then intended to hover taxi to the fuel island for fuel. He observed people and an aircraft near the fuel island, and he hover taxied to a dirt area. While about 12-15 ft above ground level, the engine had a complete loss of power. He further reported that he was too low to autorotate, landed hard on uneven terrain and collapsed the left skid. An inspection revealed that both fuel tanks were empty. The helicopter sustained substantial damage to the fuselage and main rotor blades. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
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
- Fuel exhaustion during maneuvering (hover) defining event
- Loss of engine power (total) during maneuvering (hover)
- Autorotation Hard landing
The NTSB's findings
- Aircraft › Fluids/misc hardware › Fluids › Fuel › Fluid level other cases naming the fuel system
- Personnel issues › Task performance › Planning/preparation › Fuel planning › Pilot
- Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
- Personnel issues › Action/decision › Info processing/decision › Decision making/judgment › Pilot
- Environmental issues › Physical environment › Terrain › Sloped/uneven terrain › Contributed to outcome
Pilot
- Certificate: private
- Ratings: single-engine land; rotorcraft: helicopter
- Flight time: 3,100 hours in all; 5 in this make and model; 2,885 as pilot in command
- Last flight review: August 25, 2020
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 3,907 hours
- Last inspection: annual inspection, August 23, 2020; 5 hours since
- Maximum gross weight: 2,150 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming HIO-360-C1A (piston); 3,907 hours total
The flight
- Departed from: U76 Mountain Home ID at 5:30 pm
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 320° at 12 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 15,000 ft
- Temperature: 88°F (31°C), dew point 46°F (8°C)
- Altimeter: 30.14 inHg
- Observation at 11:58 am from KMUO, 8 miles away
Weather report (METAR): KMUO 281758Z AUTO 32012KT 10SM FEW150 31/08 A3014 RMK AO2 SLP174 T03060077 10306 20231 50005 $
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The NTSB has not released the docket for this case yet. The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), is usually released when the investigation is nearly complete, and the list here is refreshed when it appears. Check at the NTSB.
Connections how this case links to the rest of the register
- N46MU on the register today · the tail number may have moved to another aircraft since
- Enstrom F-28 147 registered today · the model family and its accident history
- Enstrom 216 aircraft on the register
- Engine: Lycoming HIO-360-C1A 6 aircraft carry this series today · as the NTSB recorded it
- Mountain Home Municipal · nearest airport
- Accidents and incidents in Idaho 1,535 since 1982 · 287 in the last ten years
- Idaho 4,201 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/WPR21LA293.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.