WPR11CA060 · Burkhart Grob G-103A TWIN II ACRO
Sky Sailing Burkhart Grob G-103A TWIN II ACRO · Accident: loss of control on ground during landing
From Warner Springs Gliderport Airport (CL35) to Warner Springs Gliderport Airport (CL35)
Event
- NTSB case
- WPR11CA060
- 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
Burkhart Grob G-103A TWIN II ACRO
- Aircraft type
- Grob G-103
- 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
- N855BG
- Operator
- Sky Sailing
- Onboard fatalities
- Unknown
- Route
- From Warner Springs Gliderport Airport (CL35), Warner Springs, CATo Warner Springs Gliderport Airport (CL35), Warner Springs, CA
- 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
- Landing
- 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 control on ground
- 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
- Personnel issues › Action/decision
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The certified flight instructor (CFI) stated that he was providing instruction to a student pilot in a glider. After a routine local instructional flight, they returned to the departure airport for landing. The student was flying the glider and the CFI was providing verbal instructions to him as they completed a standard traffic pattern to the dirt landing area. He reported that there was a crosswind at 12 knots, gusting to about 20 knots. The glider encountered a high sink rate and the CFI took authority over the controls. The glider ground looped, resulting in substantial damage to the tail. The CFI reported no preimpact mechanical malfunctions or failures with the glider that would have precluded normal operation.
Probable cause
The certified flight instructor's inadequate compensation for the crosswind and delayed remedial action during landing, which resulted in a ground loop.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR11CA060
- Event ID
- 20101129X31403
- Case number
- WPR11CA060
- 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: 9e28f0049616702561bfd40242388255c9699af4d2fc7519e0b445226fc5d6da; retrieved 2026-09-15T15:35:11.509Z.