# NTSB investigations: Ground resonance NTSB aviation accident and incident investigations since 1962: the probable cause, findings, aircraft, crew, weather and docket of each, linked to the FAA registry and the FAA’s own reports. ## Latest cases - [NTSB ERA25LA255](https://openairdocs.org/ntsb/ERA25LA255.md): Schweizer 269C · Madisonville, KY · Accident · Minor injuries · Class 4 · Limited · Final report · Jul 2, 2025 · N21385 · Substantial damage > The pilot’s failure to take the appropriate corrective action for ground resonance, which resulted in a loss of helicopter control. - [NTSB ERA24LA399](https://openairdocs.org/ntsb/ERA24LA399.md): Bell Textron Canada 505 · Marianna, FL · Accident · No injuries · Class 3 · Limited · Final report · Aug 23, 2024 · N945TC · Substantial damage > The student pilot’s failure to maintain rotor rpm during a simulated autorotation, which allowed for a resonance phenomenon to develop. Contributing to the accident was the flight instructor’s inadequate monitoring of the student pilot’s collective control… - [NTSB ERA23LA284](https://openairdocs.org/ntsb/ERA23LA284.md): Schweizer 269C · Macclenny, FL · Accident · Minor injuries · Class 3 · Limited · Final report · Jul 1, 2023 · N9WZ · Substantial damage > The improper maintenance of the landing gear dampers and main rotor elastomeric dampers, resulting in ground resonance during an unsuccessful takeoff attempt with the helicopter near its maximum gross weight for the density altitude. - [NTSB ERA23LA289](https://openairdocs.org/ntsb/ERA23LA289.md): Hughes 269A · Anderson, SC · Accident · No injuries · Class 4 · Limited · Final report · Jun 27, 2023 · N90270 · Substantial damage > The mechanics’ improper torquing of the main rotor blade dampers, which resulted in a ground resonance event during landing. - [NTSB ERA22LA091](https://openairdocs.org/ntsb/ERA22LA091.md): Bell Helicopter Textron Canada 429 · Manhattan, NY · Accident · No injuries · Class 4 · Limited · Final report · Dec 13, 2021 · N920PD · Substantial damage > The pilots overapplication of flight controls during landing, which resulted in the rotor blades contacting the wire strike protection system and subsequent hard landing. - [NTSB ERA19LA173](https://openairdocs.org/ntsb/ERA19LA173.md): Hughes 269B · Hampton, GA · Accident · No injuries · Class 3 · Limited · Final report · May 15, 2019 · N9422F · Substantial damage > Ground resonance during landing for reasons that could not be determined based on the available information. - [NTSB WPR18LA170](https://openairdocs.org/ntsb/WPR18LA170.md): Schweizer 269C · Las Vegas, NV · Accident · Minor injuries · Class 3 · Limited · Final report · Jun 13, 2018 · N557DC · Substantial damage > The pilot’s failure to take the appropriate corrective action for ground resonance, which resulted in a loss of helicopter control. - [NTSB CEN17LA229](https://openairdocs.org/ntsb/CEN17LA229.md): Hughes 269C · Tallulah, LA · Accident · No injuries · Limited investigation · Final report · Jun 10, 2017 · N7482F · Substantial damage > The pilot's failure to reset the cyclic trim before takeoff, which resulted in ground resonance. - [NTSB ERA16LA261](https://openairdocs.org/ntsb/ERA16LA261.md): Schweizer 269C · Calhoun, GA · Accident · No injuries · Limited investigation · Final report · Jul 16, 2016 · N6148D · Substantial damage > The helicopter owner’s failure to ensure the helicopter’s airworthiness and the inadequate inspection and maintenance of the helicopter's landing gear dampers, which resulted in ground resonance during throttle application. Contributing to the damage of the… - [NTSB ERA14LA293](https://openairdocs.org/ntsb/ERA14LA293.md): Schweizer 269C-1 · Allentown, PA · Accident · Minor injuries · Limited investigation · Final report · Jun 17, 2014 · N152CC · Substantial damage > Inadequate inspection and maintenance of the helicopter’s landing gear dampers, which resulted in ground resonance during helicopter shutdown. - [NTSB ANC14LA041](https://openairdocs.org/ntsb/ANC14LA041.md): Airbus/Eurocopter AS 350 B3 · Anchorage, AK · Accident · No injuries · Class 3 · Limited · Final report · Jun 11, 2014 · N356EV · Substantial damage > The pilot’s improper engine start procedure, which resulted in an overspeed of the engine and main rotor drive system. - [NTSB CEN14LA269](https://openairdocs.org/ntsb/CEN14LA269.md): Schweizer 269C · Temple, TX · Accident · No injuries · Limited investigation · Final report · May 31, 2014 · N902CP · Substantial damage > Ground resonance due to maintenance personnel’s improper inspection of the landing gear dampers, which resulted in the dampers operating outside of allowable limits. - [NTSB WPR13TA051](https://openairdocs.org/ntsb/WPR13TA051.md): Eurocopter AS350B3 2B1 · Newfield, AZ · Accident · Minor injuries · Final report · Nov 23, 2012 · N3984A · Substantial damage > The pilot's distraction while retrieving an item behind him while the helicopter was on the ground with the engine running, which led to his aggressive overapplication of the flight controls after experiencing a ground resonance condition and subsequent loss… - [NTSB CEN12LA343](https://openairdocs.org/ntsb/CEN12LA343.md): Schweizer 269C · Denver, CO · Accident · No injuries · Limited investigation · Final report · Jun 2, 2012 · N2196F · Substantial damage > The inadequately overhauled landing gear dampers that allowed initiation of a ground resonance event from which the pilot was unable to recover. Contributing to the accident was the overhaul facility's failure to identify the overcharged dampers and a lack of… - [NTSB CEN12LA353](https://openairdocs.org/ntsb/CEN12LA353.md): Schweizer 269C-1 · Chesterfield, MO · Accident · No injuries · Limited investigation · Final report · May 26, 2012 · N345MH · Substantial damage > The undercharged and overcharged landing gear dampers, which allowed initiation of the ground resonance event from which the pilot was unable to recover due to his limited experience in helicopters. Contributing to the accident was the ineffective damper… - [NTSB CEN12LA247](https://openairdocs.org/ntsb/CEN12LA247.md): Hughes 269A · Grinnell, IA · Accident · No injuries · Limited investigation · Final report · Apr 17, 2012 · N69HJ · Substantial damage > The pilot's improper liftoff technique, which resulted in ground resonance, and the pilot's delayed recognition of the ground resonance. - [NTSB CEN12CA031](https://openairdocs.org/ntsb/CEN12CA031.md): Hughes 269A · Fort Worth, TX · Accident · No injuries · Data collection · Final report · Oct 14, 2011 · N10375 · Substantial damage > The inadvertent entry into ground resonance after a hovering autorotation. - [NTSB ERA11LA428](https://openairdocs.org/ntsb/ERA11LA428.md): Schweizer 269C · Darlington, MD · Accident · Minor injuries · Limited investigation · Final report · Jul 29, 2011 · N39SH · Substantial damage > Inadequate maintenance of the helicopter's landing gear dampers, which resulted in a main rotor out-of-balance condition and ground resonance encounter. - [NTSB CEN10CA352](https://openairdocs.org/ntsb/CEN10CA352.md): Aerospatiale AS350 · Lake Charles, LA · Accident · No injuries · Data collection · Final report · Jun 26, 2010 · N191EH · Substantial damage > The flight instructor’s inadvertent entry into ground resonance when demonstrating a hydraulic failure running landing, which resulted in substantial damage to the helicopter. Contributing to the accident was the pilot's and instructor pilot's failure to… - [NTSB ERA09WA478](https://openairdocs.org/ntsb/ERA09WA478.md): Agusta A109E · Ras Tanajib, Saudi Arabia · Accident · No injuries · Foreign investigation · Aug 22, 2009 · N906AH · Substantial damage > On August 22, 2009, at 0506 universal coordinated time, an Agusta 109E helicopter, N906AH, operated by Saudi Aramco Aviation, sustained substantial damage during landing and a post crash fire at barge Arabyia 4, in the Persian Gulf, near Ras Tanajib, Saudi… - [NTSB NYC08CA195](https://openairdocs.org/ntsb/NYC08CA195.md): Schweizer 269C · Mt. Olive, AL · Accident · Minor injuries · Data collection · Final report · May 27, 2008 · N368HF · Substantial damage > The flight instructor's inadequate remedial action following an encounter with ground resonance. ## The whole list in SQL Runs in DuckDB 1.2 or later on the release's Parquet files over HTTPS: ```sql SELECT c."ntsbNumber", c."eventDate", c."eventType", c."eventCity", c."eventStateOrRegion", a.n_number, a."aircraftMake", a."aircraftModel", c."highestInjuryLevel", c."totalFatal", c."completionStatus", c.report_url FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = c."mKey" AND a.position = 1 WHERE c."mKey" IN (SELECT s.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_events.parquet' s WHERE s."tier2Number" = '232' AND s.case_mkey IN (SELECT case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_events.parquet' WHERE "isDefiningEvent")) ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC ``` This list as a web page: https://openairdocs.org/ntsb-events/232/sequence --- 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.