GAA18CA377 · Jonker Sailplanes (PTY) Ltd JS1-C
Jonker Sailplanes (PTY) Ltd JS1-C · Accident: loss of lift en route
From Parowan Airport (1L9) to Parowan Airport (1L9)
Event
- NTSB case
- GAA18CA377
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Jonker Sailplanes (PTY) Ltd JS1-C
- Aircraft type
- Jonker Sailplanes (pty) JS1
- Category
- Glider
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N963CG
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Parowan Airport (1L9), Parowan, UTTo Parowan Airport (1L9), Parowan, UT
- Aircraft age
- About 4 years (built 2014)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of lift
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Aircraft › Aircraft oper/perf/capability
- Environmental issues › Conditions/weather/phenomena
- Environmental issues › Physical environment
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The powered-glider pilot reported that, during the return flight to the airport after an informal glider competition, about 10,000 to 11,000 ft over mountainous terrain, he was unable to find lift, the glider descended to 9,000 ft, and he started the sustainer engine. He added that, after the glider climbed back to the initial altitude, he shut the sustainer engine off, stowed it, and continued to the destination airport.
He reported that, about 4 miles from the airport, the glider began to sink about 1,000 ft per minute. He attempted to restart the engine but was unsuccessful in the limited time available. He chose a field for an off-airport landing, the glider touched down, but the ground was slightly uneven, which resulted in the right wing dragging. The glider veered 20° to the right before coming to rest.
The glider sustained substantial damage to the horizontal stabilizer and elevator.
The pilot reported that there were no preaccident mechanical failures or malfunctions with the glider that would have precluded normal operation.
An automated weather observation station at an elevation of 7,950 ft, located about 14 miles east-southeast of the accident location, reported wind from 270° at 10 knots, gusting to 15 knots; temperature 79°F; and dew point 9F. The calculated density altitude was 10,300 ft.
Probable cause
The pilot’s inability to maintain altitude and his delayed decision to deploy the powered-glider’s engine, which necessitated an off-airport landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record GAA18CA377
- Event ID
- 20180625X02633
- Case number
- GAA18CA377
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 661a0d7ba4b294f2aa45d89ed8a4f2c214d00528f8c0080f79bde403dfdffee6; retrieved 2026-09-16T07:38:41.535Z.