SEA04FA111 · TeST TST-10 M
TeST TST-10 M · Accident: abrupt maneuver on approach
From Bergseth Field (WN76) to Bergseth Field (WN76)
Event
- NTSB case
- SEA04FA111
- 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
- 1 · 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
TeST TST-10 M
- Aircraft type
- Test TST-10
- 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
- N410JP
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Bergseth Field (WN76), Enumclaw, WATo Bergseth Field (WN76), Enumclaw, WA
- Aircraft age
- Not recorded
- 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
- Approach · VFR pattern final
- First occurrenceThe 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
- Abrupt maneuver
- 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
- Pilot in command › Aircraft control, not maintained
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The accident aircraft departed the airport under power approximately 3 hours prior to the accident. Shortly after returning to the traffic pattern for landing, witnesses observed the aircraft enter a downwind for landing to the east. A witness reported that the pilot's downwind leg appeared normal, however, the base leg to final turn was close to the runway end resulting in a higher than normal glide path to final. Shortly after crossing the landing threshold, the glider pitched up, in conjunction with the speed brakes retracting, and the pilot initiated a turn to the right (south). The pilot rolled to a wings level attitude momentarily before entering a turn to the left. As the aircraft turned to the left, it pitched to a nose-low attitude and impacted terrain. The accident flight was the pilot's first solo landing approach to the accident airport.
Probable cause
Aircraft control not maintained while maneuvering for landing. A proper glidepath was not maintained was a factor.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA04FA111
- Event ID
- 20040625X00871
- Case number
- SEA04FA111
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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: local date, investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2004-06-21.
- API snapshot SHA-256: 0143aff0970475f8a74e270772cf41266d74d5cbcdfc7994bbeedc2f1c8231ee; retrieved 2026-09-20T18:26:16.477Z.