Amateur-built GLASAIR II accident near Darby, Montana, May 29, 2021
On May 29, 2021 at about 5:06 pm local time, a 1999 amateur-built GLASAIR II, registered N8176J, was substantially damaged in an accident during approach (VFR go-around) near Darby, Montana (West Fork Lodge Airport). It was a personal flight under general aviation rules (Part 91). 2 people were seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot’s impact with terrain during a go-around following an attempted precautionary landing due to a low oil pressure indication. The reason for the low oil pressure indication could not be determined based on the available information.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 29, 2021 · about 5:06 pm local time
- Place
- Darby, Montana · West Fork Lodge Airport · map
- Type
- Accident
- Injuries
- 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Amateur-built GLASAIR II FT, built 1999
- Registration
- N8176J · registry record · serial 2123
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot was conducting a local flight with a passenger when he received a low oil pressure warning, and he decided to perform a precautionary landing to a nearby grass runway. While on final approach for landing, the pilot determined that the airplane was high and fast, and he attempted to slip to slow the airplane and descend quickly, but about halfway down the runway, chose to go around and began a turn to land in the other direction. About three-quarters of the way through the turn, the pilot “felt the airplane begin to stall.” He pushed the nose down and the airplane contacted the ground in a left-wing-low, nose-down attitude. The automotive conversion engine was rotated by hand after removal of the flywheel dampener plate. About 2 quarts of oil was drained from the engine. Examination of the crankshaft and connecting rods revealed no anomalies. The oil filter and adapter were removed, and black RTV sealant was noted around the base of the filter adapter. The oil filter element was inspected and found to contain a sliver of black RTV material; however, based on the available information, the reason for the low oil pressure indication could not be determined.
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
- Powerplant sys/comp malf/fail during enroute
- Collision during takeoff/land during approach (VFR go-around) defining event
The NTSB's findings
- Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Descent/approach/glide path › Not attained/maintained
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng oil sys › Unknown/Not determined
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 363.3 hours in all; 290 in this make and model; 5.4 in the last 90 days; 5.4 in the last 30 days; 341.1 as pilot in command
- Last flight review: April 30, 2021
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: serious injuries
Passenger
- Seat: rgt
- Injury: serious injuries
The aircraft
- Seats: 2
- Landing gear: fixed
- Engine: Eggenfellner E6 3.6 Liter (piston); 0 hours total
The flight
- Departed from: K32S Stevensville MT at 4:15 pm
- Flight plan: none
- Runway 2 /, 2,600 ft by 65 ft
Weather at the time
- Light: daylight
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 57°F (14°C), dew point 36°F (2°C)
- Altimeter: 30.20 inHg
- Observation at 11:53 am from KMSO, 58 miles away
Weather report (METAR): KMSO 291753Z VRB03KT 10SM CLR 14/02 A3020
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
5 documents, released by the NTSB on November 22, 2022. 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 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 7 pages | View Download |
| 2 | Witness Statement | PDF, 2 pages | View Download |
| 3 | FAA Engine Exam | PDF, 7 pages | View Download |
| 4 | Release of Aircraft Wreckage, NTSB Form 6120.15 | PDF, 1 page | View Download |
| 5 | Photos | PDF, 3 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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.