Amateur-built Glasair III accident near Darby, Montana, May 17, 2012
On May 17, 2012 at about 10:02 pm local time, a amateur-built Glasair III, registered N471B, was substantially damaged in an accident during landing (landing roll) near Darby, Montana. It was a positioning 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 loss of directional control during an emergency landing on a paved highway.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 17, 2012 · about 10:02 pm local time
- Place
- Darby, Montana · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built Glasair III
- Registration
- N471B · no longer on the register · serial 3380
- Damage
- Substantial damage
- Flight
- Positioning flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot reported that, about 2 hours into a visual flight rules cross-country flight, he enriched the mixture due to indications of excessive cylinder head and exhaust gas temperatures. This resulted in a higher fuel burn than planned, so he changed the flight’s destination to a closer airport. While en route to his amended destination, he encountered instrument meteorological conditions. A subsequent buildup of ice resulted in a loss of 100 knots of airspeed as the airplane entered a controlled descent. The pilot executed a 180-degree turn and broke out of the clouds over a valley. During the next 50 minutes, he made several attempts to exit the valley; however, mountain peak obscuration and a thunderstorm prevented him from flying out of the valley. Now very close to fuel exhaustion, he elected to land on a two-lane highway. During the landing roll, the airplane veered off the side of the road, impacted a tree, slid backwards through a ditch, and collided with a concrete drainage culvert. The airplane sustained damage to the outboard sections of both wings.
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
- VFR encounter with IMC during enroute (cruise)
- Off-field or emergency landing during maneuvering
- Loss of control on ground during landing (landing roll) defining event
- Runway excursion during landing (landing roll)
- Collision with terrain or object (not controlled flight into terrain) during landing (landing roll)
The NTSB's findings
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Directional control › Not attained/maintained
- cause Personnel issues › Task performance › Use of equip/info › Aircraft control › Pilot
Pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane
- Flight time: 19,896 hours in all; 4 in this make and model
- Last flight review: August 4, 2011
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 150 hours
- Last inspection: condition inspection, August 1, 2011; 3 hours since
- Seats: 2
- Landing gear: retractable
- Engine: Lycoming I-540 (piston); 0 hours total
The flight
- Departed from: TTD Troutdale OR at 7:30 pm
- Destination: BIL Billings MT
- Flight plan: VFR
Weather at the time
- Light: daylight
- Wind: from 230° at 10 knots, gusting 15
- Visibility: 10 statute miles
- Sky: broken clouds at 8,000 ft
- Temperature: 63°F (17°C), dew point 34°F (1°C)
- Altimeter: 29.79 inHg
- Observation at 9:53 pm from MSO, 60 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
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 N471B 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.