# NTSB CEN21LA157: Post Thorp T-18, N763LG, Indianapolis, IN, March 5, 2021 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 4 · Limited · Final report - Date: March 5, 2021, 16:00 local (21:00 UTC) - Place: Indianapolis, IN - Coordinates: 39.6276, -86.088 - Nearby events: https://openairdocs.org/map.md?lat=39.6276&lon=-86.0880&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: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Central Region - NTSB case key (mKey): 102752 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA157 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102752/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102752 - Page: https://openairdocs.org/ntsb/CEN21LA157 ## Probable cause The pilot’s failure to maintain directional control during landing with a crosswind. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: directional control](https://openairdocs.org/ntsb-findings/01062020): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Post THORP T-18, 1 case](https://openairdocs.org/ntsb-findings/01062020/cases.md?model=89510A1), [All aircraft, 3,958 cases](https://openairdocs.org/ntsb-findings/01062020/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Post THORP T-18, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=89510A1), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Wind: crosswind](https://openairdocs.org/ntsb-findings/03034040): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Post THORP T-18, 1 case](https://openairdocs.org/ntsb-findings/03034040/cases.md?model=89510A1), [All aircraft, 1,008 cases](https://openairdocs.org/ntsb-findings/03034040/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: [Post THORP T-18, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=89510A1), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing: Other weather encounter](https://openairdocs.org/ntsb-events/400); cases with it: [Post THORP T-18, 1 case](https://openairdocs.org/ntsb-events/400/sequence.md?model=89510A1), [All aircraft, 1,127 cases](https://openairdocs.org/ntsb-events/400/sequence.md) ## Analysis The pilot reported that during landing he was slow to react when the wind lifted the airplane’s right wing. The airplane subsequently ground looped and came to a stop in the grass median between the runway and the taxiway. The airplane sustained substantial damage to the fuselage and vertical stabilizer. The pilot reported that there were no mechanical failures or malfunctions with the airplane that would have precluded normal operation. At the time of the accident, the pilot was landing on runway 01 with wind from 060o at 9 knots. ## Aircraft - Registration: [N763LG](https://openairdocs.org/aircraft/N763LG), registered now, S/N 460 (OpenAirDocs) - Reported make and model: POST THORP T-18 - Registry model: [Post THORP T-18](https://openairdocs.org/model/post-thorp-t-18) (registry code 89510A1) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: 460 - Year built: 1979 - Airframe hours: 570.95 - Engines: LYCOMING O-360-A1A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Condition, May 30, 2020 - Departed: 3I3, Terre Haute, IN - Destination: Same as departure - Airport: HFY, Indy South Greenwood, runway 01/19, 5,102 × 75 ft, asphalt - Equipment: Electronic multifunction display, Auto-pilot ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 57; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review September 22, 2020; seat: left; restraint: 4-point; flight hours: 343 total, 69 in this make and model, 321 as pilot in command, 14 in the last 90 days, 6 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 60° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 52 °F - Altimeter: 30.28 inHg - Observed at: HFY ## 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 20210305002469A](https://openairdocs.org/incident/20210305002469A), Mar 5, 2021: Post THORP T-18, Greenwood, IN, Substantial damage. On March 5, 2021 at 1730 local, a pilot later identified as [privacy data omitted], flying a Post thorp T-18, N763LG, had an accident at Greenwood Municipal… ## Other investigations on N763LG (1) 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. - [NTSB CEN27LA002](https://openairdocs.org/ntsb/CEN27LA002), Oct 3, 2026: Post Thorp T-18 (N763LG), Brazil, IN, substantial damage, investigation ongoing ## Docket (2 files) The files NTSB released with the investigation on July 19, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102752. 2.1 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12087973&FileExtension=pdf&FileName=6120_Redacted-Rel.pdf - Photos (item 2, PDF, 2 pages, 661 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12088044&FileExtension=pdf&FileName=Photo%20Array-Rel.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.