# NTSB WPR11CA060: Burkhart Grob G-103A Twin II Acro, N855BG, Warner Springs, CA, November 26, 2010 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: November 26, 2010, 12:55 local (20:55 UTC) - Place: Warner Springs, CA - Coordinates: 33.284442, -116.67472 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=33.2844&lon=-116.6747&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Loss of control on ground](https://openairdocs.org/ntsb-events/230) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report April 12, 2011 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 77880 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11CA060 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/77880/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=77880 - Page: https://openairdocs.org/ntsb/WPR11CA060 ## Probable cause The certified flight instructor's inadequate compensation for the crosswind and delayed remedial action during landing, which resulted in a ground loop. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Wind: crosswind](https://openairdocs.org/ntsb-findings/03034040): Environmental issues › Conditions/weather/phenomena · Response/compensation (probable cause); cases with it: [Burkhart Grob G-103A TWIN II ACRO, 1 case](https://openairdocs.org/ntsb-findings/03034040/cases.md?model=1660206), [All aircraft, 1,008 cases](https://openairdocs.org/ntsb-findings/03034040/cases.md) - [Action: delayed action](https://openairdocs.org/ntsb-findings/02041025): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Burkhart Grob G-103A TWIN II ACRO, 2 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md?model=1660206), [All aircraft, 894 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md) - [Wind: crosswind](https://openairdocs.org/ntsb-findings/03034040): Environmental issues › Conditions/weather/phenomena · Effect on operation; cases with it: [Burkhart Grob G-103A TWIN II ACRO, 1 case](https://openairdocs.org/ntsb-findings/03034040/cases.md?model=1660206), [All aircraft, 1,008 cases](https://openairdocs.org/ntsb-findings/03034040/cases.md) - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Burkhart Grob G-103A TWIN II ACRO, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=1660206), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Loss of control on ground](https://openairdocs.org/ntsb-events/230) (defining event); cases with it: [Burkhart Grob G-103A TWIN II ACRO, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=1660206), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) ## Analysis 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. ## Factual narrative The certified flight instructor (CFI) was providing instruction to a student pilot in a glider. After a routine local instructional flight, they returned to the departure airport for landing. They flew a standard traffic pattern to runway 08R (dirt glider landing area) and the wind was from approximately 100 degrees at 12 knots, gusting to about 20 knots. The student was flying the glider, and the CFI was providing verbal instructions to him. The glider encountered a high sink rate, the CFI took the controls, and the glider ground looped. Post accident examination showed that the tail boom was fractured. ## Aircraft - Registration: [N855BG](https://openairdocs.org/deregistered/N855BG-2015-12-01), registration cancelled 2015-12-01, S/N 34017-K-249 (OpenAirDocs) - Reported make and model: BURKHART GROB G-103A TWIN II ACRO - Registry model: [Burkhart Grob G-103A TWIN II ACRO](https://openairdocs.org/model/burkhart-grob-g-103a-twin-ii-acro) (registry code 1660206) (OpenAirDocs) - Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs) - Category: Glider - Serial number: 34017-K-249 - Airframe hours: 7248 - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Sky Sailing Inc - Registered owner: Sky Sailing Inc - Airworthiness certificate: Standard, Aerobatic; Standard, Utility - Last inspection: Annual, August 4, 2010 - Departed: CL35, Warner Springs, CA - Destination: CL35, Warner Springs, CA - Airport: CL35, Warner Springs Gliderport, runway 08, 4,700 × 70 ft, dirt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 52; injuries: none; flight instructor, commercial; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review December 30, 2008; flight hours: 10,260 total, 2,000 in this make and model, 10,190 as pilot in command, 80 in the last 90 days - Student pilot; age 49; injuries: none; seat: front ## Weather - Conditions: Visual (VMC), Day - Wind: 300° at 8 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 64 °F, dew point 21 °F - Altimeter: 30.12 inHg - Observed at: RNM, 19 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20101126053379A](https://openairdocs.org/incident/20101126053379A), Nov 26, 2010: Burkhart Gr G-103A TWIN, Warner Springs, CA, Substantial damage. On a crosswind landing student was slow to input corrections per instructors instructions. Instructor intervened but could not fully correct prior touchdown.… ## Docket (2 files) The files NTSB released with the investigation on December 20, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=77880. 372 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 276 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40340897&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Photo 1. Glider (item 2, .PDF, 96 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40340898&FileExtension=.PDF&FileName=Photo%201.%20Glider-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.