Airbus AS-350 accident near Hamilton, Montana, May 4, 2015
On May 4, 2015 at about 4:45 pm local time, a 1984 Airbus AS-350 (helicopter), registered N504WD, was substantially damaged in an accident near Hamilton, Montana (Ravalli County airport). It was an instructional 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 excessive collective application during an autorotation. Contributing to the accident was the flight instructor's inadequate supervision of the training flight.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 4, 2015 · about 4:45 pm local time
- Place
- Hamilton, Montana · Ravalli County · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Airbus AS-350 BA, built 1984
- Registration
- N504WD · no longer on the register · serial 1800
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The flight instructor, in the left seat reported that he was providing flight instruction to the commercial pilot, in the right seat, which included a series of hovering autorotations. According to the instructor, as the commercial pilot hovered the helicopter about 3 or 4 ft above the ground, the instructor initiated the hovering autorotation by reducing the floor-mounted throttle (fuel flow control lever) to about 70% N1, and the helicopter descended to about 1 ft above the ground. As the commercial pilot tried to cushion the touchdown, he inadvertently applied too much collective pitch, and the helicopter ballooned to a higher altitude. During the second descent, the main rotor rpm continued to decay, and the helicopter’s skids struck the ground. The instructor did not take control of the helicopter during this sequence. A postflight inspection revealed substantial damage to the tailboom.
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
- Autorotation Attempted remediation/recovery
- Autorotation Hard landing defining event
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Rotorcraft flight control › Main rotor control › Incorrect use/operation
- cause Personnel issues › Task performance › Use of equip/info › Use of equip/system › Pilot
- factor Personnel issues › Psychological › Attention/monitoring › Monitoring other person › Instructor/check pilot
Pilot
- Certificate: commercial pilot, private
- Ratings: single-engine land; single-engine sea; rotorcraft: helicopter
- Flight time: 570.5 hours in all; 201.6 in this make and model; 27 in the last 90 days; 416.2 as pilot in command
- Last flight review: August 19, 2014
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
Flight instructor
- Certificate: airline transport pilot, flight instructor, flight engineer
- Ratings: multi-engine land; instructor: helicopter; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 18,000 hours in all; 500 in this make and model; 107 in the last 90 days; 24 in the last 30 days; 10,000 as pilot in command
- Last flight review: July 10, 2014
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 5,696.9 hours
- Last inspection: approved inspection programme, February 10, 2015; 31 hours since
- Maximum gross weight: 4,630 lb
- Seats: 6
- Landing gear: fixed
- Engine: Turbomeca Arriel 1B (turboshaft); 12,477 hours total
The flight
- Departed from: 6S5 Hamilton MT at 4:45 pm
- Destination: 6S5 Hamilton MT
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 52°F (11°C), dew point 28°F (-2°C)
- Altimeter: 29.95 inHg
- Observation at 4:53 pm from KMSO, 40 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 |
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.
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.