# NTSB GAA18CA283: Schweizer SGS123, N9915J, Tunbridge, VT, May 13, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: May 13, 2018, 15:36 local (19:36 UTC) - Place: Tunbridge, VT - Coordinates: 43.895832, -72.440002 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.8958&lon=-72.4400&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Loss of lift](https://openairdocs.org/ntsb-events/500) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report October 24, 2018 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 97269 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA18CA283 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/97269/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=97269 - Page: https://openairdocs.org/ntsb/GAA18CA283 ## Probable cause The student glider’s inability to maintain altitude due to a loss of thermal lift, which resulted in an off-airport landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Temp/humidity/pressure: thermal lifting](https://openairdocs.org/ntsb-findings/03031040): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Schweizer SGS 1-23H-15, 1 case](https://openairdocs.org/ntsb-findings/03031040/cases.md?model=8050112), [All aircraft, 53 cases](https://openairdocs.org/ntsb-findings/03031040/cases.md) - [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Schweizer SGS 1-23H-15, 2 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md?model=8050112), [All aircraft, 1,310 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Loss of lift](https://openairdocs.org/ntsb-events/500) (defining event); cases with it: [Schweizer SGS 1-23H-15, 2 cases](https://openairdocs.org/ntsb-events/500/sequence.md?model=8050112), [All aircraft, 252 cases](https://openairdocs.org/ntsb-events/500/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Schweizer SGS 1-23H-15, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=8050112), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Schweizer SGS 1-23H-15, 2 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=8050112), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The solo student glider pilot reported that, during the return flight to the airport, he was unable to maintain enough lift and did not have enough altitude to cross a section of forest between his location and the airport. After he selected a field for landing, during the base leg turn, he determined that he did not have enough altitude to clear a line of trees at the threshold of the field. He then continued straight ahead, parallel to the line of trees, and impacted the ground in a small clearing. The glider sustained substantial damage to the left wing and empennage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the glider that would have precluded normal operation. ## Factual narrative The solo student glider pilot reported that, during the return flight to the airport, he was unable to find enough lift and did not have enough altitude to cross a section of forest between his location and the airport. After he selected a field for landing, during the base leg turn, he determined that he did not have enough altitude to clear a line of trees at the threshold of the field. He then continued straight ahead, parallel to the line of trees, and impacted the ground in a small clearing. The glider sustained substantial damage to the left wing and empennage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the glider that would have precluded normal operation. ## Aircraft - Registration: [N9915J](https://openairdocs.org/deregistered/N9915J-2020-10-03), registration cancelled 2020-10-03, S/N 71, built 1966 (OpenAirDocs) - Reported make and model: SCHWEIZER SGS123 (H15) - Registry model: [Schweizer SGS 1-23H-15](https://openairdocs.org/model/schweizer-sgs-1-23h-15) (registry code 8050112) (OpenAirDocs) - Registry engine: [NONE](https://openairdocs.org/engine/none) (registry code 00000, none) (OpenAirDocs) - Category: Glider - Serial number: 71 - Year built: 1966 - Airframe hours: 1035 - Engines: none - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Post Mills Soaring Club Inc, doing business as Post Mills Soaring Club - Registered owner: Post Mills Soaring Club Inc - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 22, 2017 - Departed: 2B9, Post Mills, VT - Destination: 2B9, Post Mills, VT - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 78; injuries: none; student; seat: single; restraint: 3-point; flight hours: 114 total, 5 in the last 90 days, 5 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 190° at 9 knots, gusting 18 - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 72 °F, dew point 36 °F - Altimeter: 30.02 inHg - Turbulence: Light - Observed at: KLEB, 17 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 20180513007149A](https://openairdocs.org/incident/20180513007149A), May 13, 2018: Schweizer SGS 1-23H-15, Turnbridge, VT, Substantial damage. Student glider pilot departed the post mills airport (2B9) for a glider flight. As he was returning back to post mills airport in the area of tunbridge, VT… ## Docket (2 files) The files NTSB released with the investigation on August 2, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=97269. 1.0 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 868 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40465650&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Accident Picture (item 2, .PDF, 1 photo, 142 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40465651&FileExtension=.PDF&FileName=Accident%20Picture-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.