# NTSB ERA23LA216: Gilbert R. Ringer GP4, Stratford, CT, April 27, 2023 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: April 27, 2023, 09:30 local (13:30 UTC) - Place: Stratford, CT - Coordinates: 41.164347, -73.122274 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=41.1643&lon=-73.1223&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Eastern Region Aviation - Parties: TSB Canada, FAA/FSDO - NTSB case key (mKey): 107809 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA23LA216 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/107809/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=107809 - Page: https://openairdocs.org/ntsb/ERA23LA216 ## Probable cause A failure of the left main landing gear down locking mechanism, which resulted in a collapse of that landing gear and a subsequent runway excursion. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Landing gear system: main landing gear](https://openairdocs.org/ntsb-findings/01023210): Aircraft › Aircraft systems · Failure (probable cause); cases with it: [All aircraft, 241 cases](https://openairdocs.org/ntsb-findings/01023210/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing-landing roll: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) - [Landing-landing roll: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) - [Landing-landing roll: Landing gear collapse](https://openairdocs.org/ntsb-events/094); cases with it: [All aircraft, 1,787 cases](https://openairdocs.org/ntsb-events/094/sequence.md) ## Analysis The pilot/owner was landing the experimental, amateur-built airplane at the conclusion of a night cross-country flight. The pilot described that he flared the airplane slightly high and that it, “skipped and then settled.” The landing roll seemed normal until the left main landing gear collapsed and the airplane departed the runway. The pilot further characterized that the touchdown wasn’t particularly hard, compared to landings he had previously made in other airplanes. The airplane’s horizontal stabilizer and elevator were substantially damaged during the runway excursion. Following the accident, the pilot had the airplane repaired by its original builder, which included replacing a section of threaded rod on the left main landing gear that had broken, which was part of the landing gear down-locking mechanism. Based on this information, it is likely that the failure of the threaded rod resulted in the landing gear collapse and subsequent runway excursion. ## Aircraft - Registration: C-GPEX (not matched to a registry record) - Reported make and model: GILBERT R. RINGER GP4 - Category: Airplane - Serial number: GP4-438 - Year built: 2016 - Airframe hours: 57 - Engines: Lycoming IO-360-A1B 200 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, April 24, 2023, 57 hours before - Departed: BGR, Bangor, ME - Destination: Same as departure - Flight plan: VFR - Airport: BDR, Igor I Sikorsky Meml, runway 24, 4,677 × 100 ft, asphalt - Equipment: Electronic multifunction display, Electronic primary flight display, Onboard weather, Stall warning system, ADS-B, Auto-pilot, Electronic flight bag or handheld device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 68; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review November 16, 2021; seat: left; restraint: 3-point; flight hours: 1,936 total, 6 in this make and model, 1,860 as pilot in command ## Weather - Conditions: Instrument (IMC), Day - Wind: 90° at 9 knots - Visibility: 10 statute miles - Lowest ceiling: 900 ft broken - Temperature: 48 °F, dew point 43 °F - Altimeter: 30.26 inHg - Observed at: BDR - METAR: KBDR 261452Z 09009KT 10SM BKN009 09/06 A3026 RMK AO2 SLP248 T00940061 50001 ## Docket (3 files) The files NTSB released with the investigation on July 27, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=107809. 4.2 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15762708&FileExtension=pdf&FileName=6120-p_Redacted-Rel.pdf - Investigative photographs (item 2, PDF, 6 pages, 5 photos, 1.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15762848&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf - Mechanic statement (item 3, PDF, 4 pages, 4 photos, 357 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15762430&FileExtension=pdf&FileName=MechanicStatement_Redacted-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.