DEN03LA128 · Grob G103 Twin Astir
Grob G103 Twin Astir · Accident: in flight encounter with weather while maneuvering
From Morgan County Airport (42U) to an unrecorded destination
Event
- NTSB case
- DEN03LA128
- 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
Grob G103 Twin Astir
- Aircraft type
- Grob G103
- 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
- N27TA
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Morgan County Airport (42U), Morgan, UTTo not recorded
- 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
- Maneuvering
- 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
- In flight encounter with weather
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Stall/mush
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Pilot in command › Airspeed, not maintained
- Pilot in command › In-flight planning/decision, inadequate
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The two glider pilots were returning to their point of departure (a high mountain airport). The lift on the return track had deteriorated, and they decided to do an off field landing. The two pilots identified a field for a landing, but then encountered some ridge lift. They continued flying, but the new found lift again deteriorated. They reversed course towards their initial off airport landing site. After reversing course, the glider experienced "a straight level shear," the airspeed dropped from 60 knots to 40 to 42 knots. The left wing dropped approximately 20 degrees, the nose dropped and the plane rotated to the left. This positioned the glider towards the mountain slope and "head on." The rear seat pilot (pilot in command) took control of the glider at this time. The glider impacted a ridge, crushing the composite nose into the front cockpit. The front seat pilot (second pilot), died in the hospital the following morning.
Probable cause
the pilot's failure to maintain adequate airspeed which resulted in a stall/mush. Also causal was the pilot's inadequate in-flight planning/decision to fly low over a mountain ridge. Contributing factors included the wind shear, altitude/clearance, and the lack of suitable terrain for a forced landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DEN03LA128
- Event ID
- 20030716X01117
- Case number
- DEN03LA128
- 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: investigation status, coordinates. 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: 5811de015fa7e7c697d252dd2604c9568af9adcebabd399dda3f3a25a309c1e9; retrieved 2026-09-20T19:02:37.967Z.