Sportavia Putzer RF5B SPERBER accident near Lookout Pass, Montana, May 22, 2018
On May 22, 2018 at about 8:00 pm local time, a 1974 Sportavia Putzer RF5B SPERBER (glider), an amateur-built aircraft,, registered N66GL, was substantially damaged in an accident during enroute (climb to cruise) near Lookout Pass, Montana. It was a personal flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The pilot’s improper decision to continue flight toward rising terrain after the engine overheated, which necessitated a precautionary landing when the motorglider could not maintain altitude in downdrafts.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 22, 2018 · about 8:00 pm local time · cases in 2018
- Place
- Lookout Pass, Montana · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Sportavia Putzer RF5B SPERBER B, built 1974, amateur-built
- Registration
- N66GL · no longer on the register · serial 51043
- 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 reported that, during a cross-country flight and while climbing toward a mountain pass, the experimental, amateur-built motorglider's engine began to overheat. The pilot delayed the climb to allow the engine to cool down and continued toward the pass, which resulted in reduced terrain clearance. As the motorglider approached the pass, it encountered a downdraft, and the engine was unable to produce enough power to stop the descent. Due to the reduced altitude, the pilot realized that he would be unable to safely turn the glider around, so he executed a precautionary landing on a freeway. During the landing, the glider struck a freeway barrier. The pilot reported that, other than the engine overheating, there was no evidence of any preimpact mechanical anomalies with the glider 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
- Miscellaneous/other during enroute (climb to cruise)
- Other weather encounter during enroute (climb to cruise)
- Loss of lift during enroute (climb to cruise) defining event
- Off-field or emergency landing during enroute (climb to cruise)
- Collision with terrain or object (not controlled flight into terrain) during enroute (climb to cruise)
The NTSB's findings
- cause Personnel issues › Action/decision › Info processing/decision › Decision making/judgment › Pilot
- cause Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Altitude › Not attained/maintained
- Environmental issues › Conditions/weather/phenomena › Wind › Downdraft › Effect on operation
- Environmental issues › Physical environment › Object/animal/substance › (general) › Contributed to outcome
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane; rotorcraft: glider
- Flight time: 28,350 hours in all; 39 in this make and model; 39 in the last 90 days; 26,000 as pilot in command; 2,000 on instruments
- Last flight review: April 22, 2018
- Medical certificate: None
- Seat: frt
- Injury: minor injuries
The aircraft
- Last inspection: annual inspection
- Maximum gross weight: 1,500 lb
- Seats: 2
- Landing gear: retractable
- Engine: Limbach 1700E 3E (piston); 363 hours total
- Fire on the ground
The flight
- Departed from: MSO Missoula MT at 7:00 pm
- Destination: S83 Kellogg ID
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 130° at 7 knots
- Visibility: 6 statute miles
- Sky: clear
- Temperature: 54°F (12°C), dew point 43°F (6°C)
- Altimeter: 29.81 inHg
- Observation at 8:00 pm from MLP, 25 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 |
Photographs from the investigation 1 picture from the NTSB's docket, as the NTSB released them
The NTSB's photographs with the NTSB's captions, at screen size. Open a picture to see it full size or to report one that should not be shown.
Documents from the investigation the NTSB's docket: the evidence folder behind the report
4 documents, released by the NTSB on November 1, 2018. 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, 9 pages | View Download |
| 2 | Pilot's Statement | PDF, 2 pages | View Download |
| 3 | Photos | PDF, 1 page · our copy | View Download |
| 4 | Video of Accident | video | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Connections how this case links to the rest of the register
- N66GL: not on the register today · the record of its deregistration
- Sportavia Putzer 8 aircraft on the register
- Engine: Limbach 1700E 3E 17 aircraft carry this series today · as the NTSB recorded it
- Missoula Montana Airport · departed from
- Shoshone County · bound for
- Accidents and incidents in Montana 1,121 since 1982 · 166 in the last ten years
- Montana 6,044 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/WPR18LA145.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.