# Accessory gear-boxes - Type: NTSB finding section - Path: [Aircraft](https://openairdocs.org/ntsb-findings/01) › [Aircraft power plant](https://openairdocs.org/ntsb-findings/0105) › Accessory gear-boxes - NTSB code: 010583 - Cases: 19 - In the probable cause: 17 - Fatal cases: 2 - All cases: https://openairdocs.org/ntsb-findings/010583/cases.md - Cases with it in the probable cause: https://openairdocs.org/ntsb-findings/010583/cases.md?cause=1 - Page: https://openairdocs.org/ntsb-findings/010583 ## Cases per year (in the probable cause / all) - 2008: 1 / 1 - 2009: 1 / 1 - 2010: 1 / 1 - 2011: 1 / 1 - 2012: 2 / 2 - 2013: 2 / 2 - 2014: 1 / 1 - 2015: 2 / 2 - 2018: 1 / 2 - 2019: 1 / 1 - 2022: 1 / 2 - 2023: 3 / 3 ## Findings - [Accessory gear-boxes, general](https://openairdocs.org/ntsb-findings/01058300): 19 cases, 17 in the probable cause ## Defining events in these cases - [Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340): 8 cases - [Loss of engine power (total)](https://openairdocs.org/ntsb-events/341): 6 cases - [Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342): 2 cases - [External load event (Rotorcraft)](https://openairdocs.org/ntsb-events/480): 1 cases - [Low altitude operation/event](https://openairdocs.org/ntsb-events/220): 1 cases - [Fire/smoke (non-impact)](https://openairdocs.org/ntsb-events/150): 1 cases ## Aircraft models (registry) - [Sikorsky S-61A](https://openairdocs.org/model/sikorsky-s-61a): 1 cases - [Robinson Helicopter R44](https://openairdocs.org/model/robinson-helicopter-r44): 1 cases - [Rockwell International S-2R](https://openairdocs.org/model/rockwell-international-s-2r): 1 cases - [Piper PA-32R-301T](https://openairdocs.org/model/piper-pa-32r-301t): 1 cases - [Piper PA-28-140](https://openairdocs.org/model/piper-pa-28-140): 1 cases - [Piper PA-25-235](https://openairdocs.org/model/piper-pa-25-235): 1 cases - [Piper PA-24-260](https://openairdocs.org/model/piper-pa-24-260): 1 cases - [Piper J3C-65](https://openairdocs.org/model/piper-j3c-65): 1 cases - [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d): 1 cases - [Bell 206B](https://openairdocs.org/model/bell-206b): 1 cases ## Other findings in the same cases - [Not determined, general](https://openairdocs.org/ntsb-findings/05000000) (Not determined): 2 cases - [Installation](https://openairdocs.org/ntsb-findings/02062035) (Personnel issues): 2 cases - [Altitude](https://openairdocs.org/ntsb-findings/01062012) (Aircraft): 2 cases - [Recip eng rear section](https://openairdocs.org/ntsb-findings/01058540) (Aircraft): 2 cases - [Maintenance/inspections, general](https://openairdocs.org/ntsb-findings/01010500) (Aircraft): 2 cases - [Availability of policy/proc](https://openairdocs.org/ntsb-findings/04021010) (Organizational issues): 1 cases - [Fence/fence post](https://openairdocs.org/ntsb-findings/03022047) (Environmental issues): 1 cases - [Wet/muddy terrain](https://openairdocs.org/ntsb-findings/03021035) (Environmental issues): 1 cases - [Rough terrain](https://openairdocs.org/ntsb-findings/03021015) (Environmental issues): 1 cases - [Runway/landing area condition](https://openairdocs.org/ntsb-findings/03017035) (Environmental issues): 1 cases ## Newest cases - [NTSB ERA24FA050](https://openairdocs.org/ntsb/ERA24FA050), Nov 27, 2023: Piper PA32R (N4187Q), Attalla, AL, destroyed, 1 fatal. Probable cause: The undetected wear of both pawl retaining rivets of the left magneto impulse coupling and fatigue failure of one pawl retaining rivet, which led to cascading fractures of the second pawl retaining… - [NTSB CEN24LA027](https://openairdocs.org/ntsb/CEN24LA027), Oct 26, 2023: Robinson Helicopter R44 (N141CD), Rowlett, TX, substantial damage. Probable cause: A malfunction of the helicopter’s Engine Monitoring Unit (EMU)/Governor Controller for undetermined reasons. Contributing to the accident was the flight instructor’s failure to turn off the… - [NTSB WPR23LA215](https://openairdocs.org/ntsb/WPR23LA215), Jun 4, 2023: Piper J3C-65 (N77583), Belfair, WA, substantial damage. Probable cause: The total loss of engine power due to the fatigue failure of the crankshaft accessory drive gear. - [NTSB ERA22LA268](https://openairdocs.org/ntsb/ERA22LA268), May 9, 2022: Wingren Norman Escapade (N86RD), Brasstown, NC, substantial damage. Probable cause: The failure of the engine gearbox drive flange, which resulted in a nose gear collapse during the subsequent precautionary landing in tall grass. - [NTSB ERA22LA117](https://openairdocs.org/ntsb/ERA22LA117), Feb 9, 2022: Hughes 369D (N9159F), Bel Air, MD, substantial damage. Probable cause: A loss of engine power due to bearing failures in the turbine section resulting from a fatigue fracture of the oil supply line that fed oil to the Nos. 6 and 7 bearings. The oil line failure led to… - [NTSB CEN19LA156](https://openairdocs.org/ntsb/CEN19LA156), May 25, 2019: Rockwell S 2R (N4907X), Oakes, ND, substantial damage. Probable cause: The failure of the helical cam gear of the engine assembly due to fatigue cracks in the gear teeth, which resulted in a total loss of engine power. - [NTSB WPR19LA029](https://openairdocs.org/ntsb/WPR19LA029), Nov 19, 2018: BKF Backcountry Supercub (N59BK), Casper, WY, substantial damage. Probable cause: The seizure of two bearings in the reduction gearbox, resulting in the total loss of engine power. Contributing to the accident was a high descent rate which resulted in a hard landing. - [NTSB CEN18LA281](https://openairdocs.org/ntsb/CEN18LA281), Jul 19, 2018: Piper PA28 (N7080F), Shreveport, LA, substantial damage. Probable cause: The partial loss of engine power for reasons that could not be determined based on the available evidence. - [NTSB CEN16LA035](https://openairdocs.org/ntsb/CEN16LA035), Nov 3, 2015: Glimn Kitfox 2-3 (N93TG), Escanaba, MI, substantial damage. Probable cause: The airplane owner's inadequate maintenance and servicing of the propeller gearbox, which resulted in oil starvation, failure of the gearbox in flight, and a subsequent loss of propeller thrust.… - [NTSB WPR15LA248](https://openairdocs.org/ntsb/WPR15LA248), Aug 20, 2015: Sikorsky S 61A (N1043T), Ironside, OR, substantial damage. Probable cause: A loss of power to the No. 2 engine due to the failure of the accessory gearbox drivetrain. Also causal was the pilot’s inability to release the external longline due to the use of a safety wire… NTSB has coded findings and defining events since 2008; earlier cases used its older occurrence and cause codes and aren't counted. Findings: https://openairdocs.org/ntsb-findings.md. Defining events: https://openairdocs.org/ntsb-events.md. Phases of flight: https://openairdocs.org/ntsb-phases.md. Every investigation, filtered by finding, event, phase, state, year or model: https://openairdocs.org/ntsb.md (for example ?state=MI&fatal=1). NTSB's definitions: Accident and incident, 49 CFR 830.2 (https://www.ecfr.gov/current/title-49/subtitle-B/chapter-VIII/part-830/subpart-A/section-830.2), CICTT occurrence categories (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/OccurrenceCategoryDefinitions.pdf), CICTT phases of flight (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/PhaseofFlightDefinitions.pdf), and NTSB coding manual, before 2008 (PDF) (https://www.ntsb.gov/GILS/Documents/codman.pdf). NTSB publishes no definitions for its findings, only their names. --- 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.