# NTSB investigations: Main rotor system

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.

Page 1 of 3 · 104 cases

## Latest cases

- [NTSB CEN26LA081](https://openairdocs.org/ntsb/CEN26LA081.md): Ela ELA10 · Morris, IL · Accident · No injuries · Class 4 · Limited · Final report · Dec 23, 2025 · N396S · Substantial damage
  > The pilot’s failure obtain the proper rotor rpm before applying power for the takeoff roll which resulted in a loss of control.
- [NTSB WPR25LA203](https://openairdocs.org/ntsb/WPR25LA203.md): Robinson Helicopter R44 · Park City, UT · Accident · No injuries · Class 4 · Limited · Final report · Jul 6, 2025 · N715SG · Substantial damage
  > The pilot’s failure to maintain rotor rpm during an approach to landing in a mountainous area, which resulted in a collision with terrain.
- [NTSB WPR25LA093](https://openairdocs.org/ntsb/WPR25LA093.md): Airbus Helicopters EC 130 T2 · Moab, UT · Accident · No injuries · Class 4 · Limited · Final report · Feb 13, 2025 · N3WL · Substantial damage
  > The inflight collision with debris during takeoff.
- [NTSB WPR25LA010](https://openairdocs.org/ntsb/WPR25LA010.md): Enstrom Helicopter 280C · Vale, OR · Accident · No injuries · Class 4 · Limited · Final report · Oct 9, 2024 · N646H · Substantial damage
  > The pilot’s failure to maintain engine and rotor rpm during takeoff, that resulted in a hard landing.
- [NTSB WPR24LA319](https://openairdocs.org/ntsb/WPR24LA319.md): Bell 206L · Fern Prairie, WA · Accident · No injuries · Class 3 · Limited · Final report · Sep 26, 2024 · N9984K · Substantial damage
  > An aeroelastic interaction between the helicopter’s main rotor blades and nodal beam system, which resulted in oscillations that exceeded the design limits of the tailboom. Contributing to the accident was the failure of the main rotor blade manufacturer to…
- [NTSB CEN24LA358](https://openairdocs.org/ntsb/CEN24LA358.md): Hughes 369 · Canton, MI · Accident · No injuries · Class 3 · Limited · Final report · Sep 11, 2024 · N8969F · Substantial damage
  > Fatigue cracking of the main rotor blade that occurred at an undetermined time.
- [NTSB ANC24FA063](https://openairdocs.org/ntsb/ANC24FA063.md): Robinson Helicopter R44 · Kekaha, HI · Accident · 3 fatal · Class 3 · Field · Final report · Jul 11, 2024 · N144KW · Substantial damage
  > An encounter with turbulence due to downdraft winds that resulted in mast bumping and an in-flight breakup.
- [NTSB CEN24LA013](https://openairdocs.org/ntsb/CEN24LA013.md): Magni M24 · Mount Sterling, IL · Accident · No injuries · Class 3 · Limited · Final report · Oct 16, 2023 · N90HM · Substantial damage
  > The pilot’s failure to maintain gyroplane control on the downwind leg, which resulted in impact with terrain. Contributing to the accident was the pilot’s distraction.
- [NTSB WPR23LA313](https://openairdocs.org/ntsb/WPR23LA313.md): Bell OH-58A · Guernsey, CA · Accident · Minor injuries · Class 3 · Limited · Final report · Aug 9, 2023 · N861CC · Substantial damage
  > The pilot’s overpitching of the main rotor blades while maneuvering at low altitude in a high-temperature environment at high gross weight, which resulted in a reduction of engine and rotor speed, excessive main rotor blade flapping, mast bumping, and impact…
- [NTSB ERA23LA326](https://openairdocs.org/ntsb/ERA23LA326.md): Hughes 369 · Elberon, VA · Accident · Serious injuries · Class 4 · Limited · Final report · Aug 5, 2023 · N353AH · Substantial damage
  > The pilot’s failure to maintain clearance from a power line structure arm, which resulted in main rotor blade contact.
- [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 CEN23LA199](https://openairdocs.org/ntsb/CEN23LA199.md): Bell Helicopter Textron Canada 407 · Abbeville, LA · Accident · No injuries · Class 4 · Limited · Final report · May 23, 2023 · N451PH · Substantial damage
  > The pilot’s failure to maintain proper helicopter control during autorotation that resulted in an abnormal ground contact which caused the subsequent main rotor strike on the tail boom that severed the tail rotor driveshaft. Contributing to the accident was…
- [NTSB ERA23LA228](https://openairdocs.org/ntsb/ERA23LA228.md): Robinson Helicopter R44 II · Bradenton, FL · Accident · No injuries · Class 4 · Limited · Final report · May 11, 2023 · N62HT · Substantial damage
  > The pilot’s failure to maintain adequate rotor rpm during landing which resulted in a premature landing on uneven ground and a subsequent rollover.
- [NTSB WPR22LA291](https://openairdocs.org/ntsb/WPR22LA291.md): Airbus Helicopters AS350B3 · Chino, CA · Accident · No injuries · Class 4 · Limited · Final report · Aug 4, 2022 · N833SB · Substantial damage
  > The subsequent delamination of the main rotor blades as a result of an unidentified main rotor blade impact with vegetation during a previous flight by another pilot.
- [NTSB CEN22LA318](https://openairdocs.org/ntsb/CEN22LA318.md): Hiller UH12E · Becker, MN · Accident · Serious injuries · Class 3 · Limited · Final report · Jul 6, 2022 · N64272 · Substantial damage
  > The in-flight failure of the main rotor mast hub due to several undetected fatigue fractures.
- [NTSB ERA22FA207](https://openairdocs.org/ntsb/ERA22FA207.md): Bell Helicopter Textron Canada 429 · Elba, NY · Accident · 2 fatal · Class 3 · Field · Final report · Apr 26, 2022 · N507TJ · Substantial damage
  > The pilots’ inappropriate flight control inputs while in vortex ring state, which resulted in main rotor blade contact with the tail boom and a subsequent in-flight breakup. Also causal was the flight instructor’s inadequate monitoring of the flight.
- [NTSB ERA22FA105](https://openairdocs.org/ntsb/ERA22FA105.md): Eurocopter Deutschland EC135 P2+ · Drexel Hill, PA · Accident · Serious injuries · Class 3 · Field · Final report · Jan 11, 2022 · N531LN · Substantial damage
  > An inflight attitude upset for undetermined reasons that resulted in a rotor system overspeed, a reduction of power from both engines, and a subsequent hard landing.
- [NTSB ERA21FA317](https://openairdocs.org/ntsb/ERA21FA317.md): Rotorway Exec 162F · Argyle, NY · Accident · 2 fatal · Class 3 · Field · Final report · Aug 7, 2021 · N162KJ · Destroyed
  > The pilot’s abrupt control inputs, which resulted in a low G condition, main rotor mast bumping, and the subsequent severing of the tail boom by a main rotor blade.
- [NTSB WPR21FA300](https://openairdocs.org/ntsb/WPR21FA300.md): Robinson Helicopter R66 · Colusa, CA · Accident · 4 fatal · Class 3 · Field · Final report · Aug 1, 2021 · N7000J · Destroyed
  > The pilot’s abrupt flight control input that led to mast bumping and a subsequent in-flight breakup.
- [NTSB CEN21FA330](https://openairdocs.org/ntsb/CEN21FA330.md): Robinson R44 · Elgin, MN · Accident · 1 fatal · Class 3 · Field · Final report · Jul 19, 2021 · N44BJ · Destroyed
  > The pilot’s decision to operate the helicopter under powerlines, which resulted in a main rotor blade striking a powerline, causing the helicopter to descend from a low altitude and impact terrain.
- [NTSB ERA21LA126](https://openairdocs.org/ntsb/ERA21LA126.md): Bell 206 · Pahokee, FL · Accident · No injuries · Class 3 · Limited · Final report · Feb 4, 2021 · N820H · Substantial damage
  > A loss of main rotor rpm for reasons that could not be determined, which resulted in an autorotation and a subsequent hard landing and rollover.
- [NTSB CEN21LA102](https://openairdocs.org/ntsb/CEN21LA102.md): Hughes 369D · Tuckers Crossing, MS · Accident · 1 fatal · Class 3 · Limited · Final report · Dec 29, 2020 · N103SU · Destroyed
  > The pilot’s loss of helicopter control when the external saw contacted trees during an attempted emergency landing due to a main rotor transmission oil pressure warning. The reason that the pilot did not release the external saw from the helicopter during the…
- [NTSB WPR20LA283](https://openairdocs.org/ntsb/WPR20LA283.md): Kaman K 1200 · Pine Grove, OR · Accident · 1 fatal · Class 3 · Limited · Final report · Aug 25, 2020 · N314 · Substantial damage
  > An in-flight breakup resulting from contact of the left rotor system with the right rotor system after an in-flight failure of a servo flap from a left rotor blade.
- [NTSB CEN20CA334](https://openairdocs.org/ntsb/CEN20CA334.md): Hughes 369 · Delia, KS · Accident · No injuries · Class 4 · Data collection · Final report · Aug 5, 2020 · N104SU · Substantial damage
  > Foreign object damage sustained to the main rotor blades due to aerial tree trimming.
- [NTSB WPR20LA155](https://openairdocs.org/ntsb/WPR20LA155.md): CSP Leasing Cavalon · Roseburg, OR · Accident · 1 fatal · Class 3 · Limited · Final report · May 28, 2020 · N477AG · Destroyed
  > A substantially unweighted rotor system for reasons that could not be determined, which resulted in contact between the main rotor blade and the gyrocopter’s keel tube and a loss of control and impact with terrain.
- [NTSB ENG20IA005](https://openairdocs.org/ntsb/ENG20IA005.md): Agusta A109 · Penobscot, ME · Incident · No injuries · Class 3 · Incident · Final report · Nov 16, 2019 · N901EM · Minor damage
  > Fatigue fracture of the main rotor blade tip cap leading edge and subsequent partial separation of the tip cap, resulting in increased vibrations in the main rotor.
- [NTSB WPR19LA221](https://openairdocs.org/ntsb/WPR19LA221.md): AutoGyro Cavalon · Shelton, WA · Accident · Minor injuries · Class 3 · Limited · Final report · Aug 15, 2019 · N477AG · Substantial damage
  > The pilot’s failure to initiate the takeoff roll with inadequate rotor speed, and his failure to follow the published takeoff procedures, which resulted in a loss of control and impact with the ground.
- [NTSB WPR19FA123](https://openairdocs.org/ntsb/WPR19FA123.md): Robinson R44 · Kailua, HI · Accident · 3 fatal · Class 3 · Field · Final report · Apr 29, 2019 · N808NV · Destroyed
  > The helicopter’s encounter with a strong downdraft or outflow boundary while operating at a higher than recommended airspeed in turbulence which resulted in a low-G condition, excessive main rotor flapping, and an in-flight breakup when the main rotor…
- [NTSB WPR18LA242](https://openairdocs.org/ntsb/WPR18LA242.md): Bell 212 · Dardanelle, CA · Accident · Serious injuries · Class 3 · Limited · Final report · Aug 25, 2018 · N512TA · Substantial damage
  > An in-flight failure of the trunnion bearing and subsequent failure of the drive link and swashplate support, which resulted in the loss of helicopter control.
- [NTSB GAA18CA506](https://openairdocs.org/ntsb/GAA18CA506.md): Hughes 369 · Ridgeway, PA · Accident · No injuries · Data collection · Final report · Aug 22, 2018 · N89ZC · Substantial damage
  > The pilot's failure to maintain clearance from power lines during an aerial observation flight.
- [NTSB ERA17FA317](https://openairdocs.org/ntsb/ERA17FA317.md): Schweizer 269C · Medford, NJ · Accident · 2 fatal · Field investigation · Final report · Sep 8, 2017 · N204HF · Substantial damage
  > The pilot's early entry into and failure to maintain rotor rpm during a forced landing autorotation after performing an engine shutdown in flight, which resulted in an uncontrolled descent. Contributing to the accident was the failure of maintenance personnel…
- [NTSB ERA17LA257](https://openairdocs.org/ntsb/ERA17LA257.md): Robinson Helicopter R44 · Myrtle Beach, SC · Accident · No injuries · Limited investigation · Final report · Jul 24, 2017 · N828RD · Substantial damage
  > A loss of available power to the main rotor due to a fractured exhaust pushrod and housing, which allowed engine oil to coat the V-belts. Contributing to the accident was the pilot's decision to continue the tour and his failure to maintain adequate rotor rpm…
- [NTSB WPR17LA158](https://openairdocs.org/ntsb/WPR17LA158.md): Enstrom F 28C · Ontario, CA · Accident · Serious injuries · Limited investigation · Final report · Jul 19, 2017 · N5697B · Substantial damage
  > The student pilot's mismanagement of the main rotor rpm, which resulted in low rotor rpm, a high descent rate, and a subsequent hard landing.
- [NTSB CEN17LA264](https://openairdocs.org/ntsb/CEN17LA264.md): Bell 47D1 · Big Lake, MN · Accident · No injuries · Limited investigation · Final report · Jul 6, 2017 · N153B · Substantial damage
  > The failure of the metal core assembly within a wooden main rotor blade due to undetected corrosion and fatigue, which caused the wooden blade to separate from the rotor mast.
- [NTSB ERA17LA032](https://openairdocs.org/ntsb/ERA17LA032.md): Bell OH 58C · Cameron, NC · Accident · Minor injuries · Limited investigation · Final report · Nov 1, 2016 · N139RD · Substantial damage
  > An in-flight failure of a main rotor blade due to fatigue cracks. Contributing to the failure of the main rotor blade was the absence of guidance to the operator to inspect an area of the main rotor blade known to be susceptible to fatigue cracks and the…
- [NTSB CEN17FA012](https://openairdocs.org/ntsb/CEN17FA012.md): Fairchild Hiller FH 1100 · Lino Lakes, MN · Accident · 2 fatal · Field investigation · Final report · Oct 6, 2016 · N4035G · Destroyed
  > The separation of the main rotor assembly due to mast bumping.
- [NTSB ERA16CA313](https://openairdocs.org/ntsb/ERA16CA313.md): Bell Helicopter Textron Canada 429 · Rikers Island, NY · Accident · No injuries · Data collection · Final report · Sep 1, 2016 · N917PD · Substantial damage
  > The pilot’s overcontrolling of the helicopter during an aborted slope landing from a hover, which resulted in a main rotor blade strike.
- [NTSB CEN16LA330](https://openairdocs.org/ntsb/CEN16LA330.md): Hiller UH 12D · Cokeville, WY · Accident · Minor injuries · Limited investigation · Final report · Aug 23, 2016 · N97TH · Substantial damage
  > Failure of the control rotor cuff due to fatigue.
- [NTSB DCA16FA199](https://openairdocs.org/ntsb/DCA16FA199.md): Bell 525 · Italy, TX · Accident · 2 fatal · Class 2 · Field · Final report · Jul 6, 2016 · N525TA · Destroyed
  > A severe vibration of the helicopter that led to the crew's inability to maintain sufficient rotor rotation speed (Nr), leading to excessive main rotor blade flapping, subsequent main rotor blade contact with the tail boom, and the resultant in-flight…
- [NTSB WPR16FA130](https://openairdocs.org/ntsb/WPR16FA130.md): Robinson Helicopter R66 · Wikieup, AZ · Accident · 2 fatal · Field investigation · Final report · Jun 23, 2016 · N117TW · Destroyed
  > An encounter with turbulence due to updrafts and/or dust devils that resulted in mast bumping and an in-flight break-up.
- [NTSB WPR16LA069](https://openairdocs.org/ntsb/WPR16LA069.md): Bell 47G 3B 1 · Carson City, NV · Accident · Minor injuries · Limited investigation · Final report · Feb 13, 2016 · N1181W · Substantial damage
  > The pilot's failure to maintain sufficient main rotor rpm, which resulted in a loss of helicopter control and a dynamic rollover.
- [NTSB WPR16LA081](https://openairdocs.org/ntsb/WPR16LA081.md): Mcdonnell Douglas Helicopter 600N · Ashland, OR · Accident · No injuries · Limited investigation · Final report · Feb 5, 2016 · N745BW · Substantial damage
  > Fatigue cracking of a main rotor blade for reasons that could not be determined based on the available information.
- [NTSB CEN16LA040](https://openairdocs.org/ntsb/CEN16LA040.md): Robinson Helicopter R22 Beta · Sugarland, TX · Accident · Minor injuries · Limited investigation · Final report · Nov 14, 2015 · N7058Z · Substantial damage
  > The overspeed of the main rotor system for reasons that could not be determined based on the available information.
- [NTSB GAA15CA258](https://openairdocs.org/ntsb/GAA15CA258.md): Airbus AS350 · Draper, UT · Accident · No injuries · Data collection · Final report · Sep 9, 2015 · N253HP · Substantial damage
  > The ground recovery team member's failure to secure a rescue rope during the helicopter loading process in steep terrain, resulting in the rope fouling the helicopter's main rotor system.
- [NTSB WPR15LA249](https://openairdocs.org/ntsb/WPR15LA249.md): Schweizer 269C - Undesignat · Mesa, AZ · Accident · Minor injuries · Limited investigation · Final report · Aug 23, 2015 · N315TV · Substantial damage
  > The disbondment of a main rotor damper, which resulted in the degradation of its damping action and led to excessive main rotor vibrations and oscillations that caused substantial damage to the helicopter in flight and led to a hard landing.
- [NTSB GAA15CA221](https://openairdocs.org/ntsb/GAA15CA221.md): Bell 47D1 · Clanton, AL · Accident · No injuries · Data collection · Final report · Aug 11, 2015 · N74823 · Substantial damage
  > The student pilot's abrupt cyclic and collective inputs during the approach to land which resulted in abnormal runway contact and a subsequent tail boom strike by the main rotor blades.
- [NTSB GAA15LA191](https://openairdocs.org/ntsb/GAA15LA191.md): Celier Xenon RST · Livingston, TX · Accident · Minor injuries · Limited investigation · Final report · Jul 17, 2015 · N402ED · Substantial damage
  > The pilot’s loss of directional control after aborting the takeoff due to a grinding noise coming from the main rotor area, which resulted in a runway excursion.
- [NTSB GAA15CA181](https://openairdocs.org/ntsb/GAA15CA181.md): Robinson Helicopter R22 Beta · Caldwell, ID · Accident · No injuries · Data collection · Final report · Jul 13, 2015 · N184SH · Substantial damage
  > Abnormal ground contact during a 180 degree autorotation, resulting in a severed tail rotor driveshaft by a main rotor blade. A factor contributing to the accident was the rotor blowback condition due to the aft tilting of the main rotor disk.
- [NTSB WPR15LA178](https://openairdocs.org/ntsb/WPR15LA178.md): Garlick Helicopters UH 1H · Cove, OR · Accident · No injuries · Limited investigation · Final report · May 31, 2015 · N462CC · Substantial damage
  > The failure of the engine-to-transmission drive shaft coupling assembly due to a fatigue fracture of one of its attachment bolts, which resulted in a loss of power to the main rotor.
- [NTSB ERA15LA115](https://openairdocs.org/ntsb/ERA15LA115.md): Piper PA-28R-200 · West Palm Beach, FL · Accident · No injuries · Limited investigation · Final report · Jan 28, 2015 · N54380 · 2 aircraft · Minor damage
  > The failure of the airplane pilots to maintain an adequate visual lookout for known traffic in the traffic pattern, which resulted in a midair collision. Contributing to the accident was the failure of the airplane pilots to announce their intentions before…

Next page: https://openairdocs.org/ntsb-findings/010462/cases.md?page=2

## 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 f.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_findings.parquet' f WHERE starts_with(f."findingCode", '010462'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-findings/010462/cases

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