# NTSB investigations: Main rotor blade 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 2 · 60 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 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 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 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 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 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 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 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 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 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 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 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…
- [NTSB CEN14LA508](https://openairdocs.org/ntsb/CEN14LA508.md): Brupbacher Chris CB2000 · Reserve, LA · Accident · 2 fatal · Limited investigation · Final report · Sep 21, 2014 · N5002E · Destroyed
  > The failure of the flight control rod bearing due to an undetected preexisting corrosion-induced crack, which resulted in the main rotor blades going to full pitch and the rotor mast folding; this allowed the pusher propeller to strike and sever the tail.
- [NTSB WPR14LA308](https://openairdocs.org/ntsb/WPR14LA308.md): Mdhi 369D · Oso, WA · Accident · Serious injuries · Limited investigation · Final report · Jul 22, 2014 · N5225C · Substantial damage
  > The pilot/mechanic’s failure to properly perform required inspections of the main rotor blades at the necessary intervals, which resulted in an in-flight separation of a main rotor blade due to disbonding and fatigue cracking. Contributing to the accident was…
- [NTSB CEN14TA116](https://openairdocs.org/ntsb/CEN14TA116.md): Autogyro Mtosport · Spring, TX · Accident · Minor injuries · Final report · Jan 16, 2014 · N250TX · Substantial damage
  > The pilot’s failure to maintain the gyroplane’s rotor control during the landing roll in gusting crosswind conditions.
- [NTSB ERA13LA433](https://openairdocs.org/ntsb/ERA13LA433.md): Enstrom F-28C · Bloomsburg, PA · Accident · 1 fatal · Limited investigation · Final report · Sep 27, 2013 · N631DP · Minor damage
  > The relieved pilot’s failure to maintain clearance from the rotating main rotor blades after he exited the helicopter.
- [NTSB ERA13TA237](https://openairdocs.org/ntsb/ERA13TA237.md): Bell OH-58C · Jekyll Island, GA · Accident · No injuries · Final report · May 9, 2013 · N927SP · Substantial damage
  > The pilot's failure to maintain rotor rpm in the normal operating range during a practice autorotation, which resulted in a hard landing. Contributing to the accident was the inadequate supervision by the flight instructor.
- [NTSB ERA12LA379](https://openairdocs.org/ntsb/ERA12LA379.md): Bell 427 · Indiantown, FL · Accident · Minor injuries · Limited investigation · Final report · Jun 4, 2012 · N427AL · Substantial damage
  > The inflight collision with birds, resulting in damage to the rotor head assembly and a subsequent forced landing and rollover.
- [NTSB ERA12LA373](https://openairdocs.org/ntsb/ERA12LA373.md): Faltin John R Rotorway Exec 162F · Smoketown, PA · Accident · Minor injuries · Limited investigation · Final report · May 31, 2012 · N8707E · Substantial damage
  > A loss of control during a post-maintenance test flight due to improper tracking of the helicopter’s main rotor blades by the pilot/aircraft builder.
- [NTSB WPR12LA115](https://openairdocs.org/ntsb/WPR12LA115.md): Texas Helicopter OH-13E/M74 · Farmington, CA · Accident · Serious injuries · Limited investigation · Final report · Feb 22, 2012 · N43921 · Substantial damage
  > The in-flight separation of the wood portion of one main rotor blade while maneuvering at low level, the reason for which could not be determined because postaccident examination did not reveal any anomalies that would have precluded normal operation.
- [NTSB ANC12CA018](https://openairdocs.org/ntsb/ANC12CA018.md): Robinson Helicopter R44 II · Beluga, AK · Accident · No injuries · Data collection · Final report · Jan 21, 2012 · N4510T · Substantial damage
  > Ground personnel's movement of cargo in windy conditions, which allowed a previously secured cargo sack to blow into the main rotor blades.
- [NTSB ERA12CA124](https://openairdocs.org/ntsb/ERA12CA124.md): Chapel Robert B Aerial · Simsbury, CT · Accident · No injuries · Data collection · Final report · Dec 26, 2011 · N435AB · Substantial damage
  > The pilot's decision to operate the gyroplane outside his endorsement limitations and to depart with a tailwind, which resulted in a forced landing to unsuitable terrain.
- [NTSB CEN12CA078](https://openairdocs.org/ntsb/CEN12CA078.md): Messerschmitt-Bolkow-Blohm BK 117 B-2 · Carbondale, IL · Accident · No injuries · Data collection · Final report · Nov 13, 2011 · N330SL · Substantial damage
  > The main rotor blade’s contact with the vertical stabilizer during the engine shutdown in strong, gusty wind conditions.
- [NTSB CEN12LA039](https://openairdocs.org/ntsb/CEN12LA039.md): Eurocopter AS 350 B2 · South Pass 93A · Accident · No injuries · Limited investigation · Final report · Oct 7, 2011 · N183EH · Substantial damage
  > Improper centering of the cyclic during a start in gusty wind conditions.
- [NTSB WPR11LA379](https://openairdocs.org/ntsb/WPR11LA379.md): Bell 47G-3B-2 · Los Banos, CA · Accident · No injuries · Limited investigation · Final report · Aug 14, 2011 · N475AL · Substantial damage
  > The pilot’s inadequate preflight, and contamination of both the engine compressor section and the main rotor blades, which resulted in reduced performance of the engine and rotor system.
- [NTSB CEN11FA422](https://openairdocs.org/ntsb/CEN11FA422.md): Robinson R22 Beta · Del Valle, TX · Accident · 1 fatal · Field investigation · Final report · Jun 27, 2011 · N7779M · Substantial damage
  > The divergence of the main rotor from its normal plane of rotation for reasons that cannot be determined because the pilot’s control inputs leading up to the event are unknown, resulting in mast bumping and main rotor blade separation.
- [NTSB WPR11LA048](https://openairdocs.org/ntsb/WPR11LA048.md): MD Helicopter 369D · Salem, OR · Accident · Serious injuries · Limited investigation · Final report · Nov 15, 2010 · N155PH · Substantial damage
  > The pilot’s failure to maintain clearance between the longline and trees, which resulted in the longline snagging a tree and then recoiling into the main rotor blades and a subsequent loss of helicopter control.
- [NTSB ERA10LA379](https://openairdocs.org/ntsb/ERA10LA379.md): Garlick Helicopters OH-58A+ · Newport, TN · Accident · Minor injuries · Limited investigation · Final report · Jul 28, 2010 · N48LA · Substantial damage
  > Inadequate maintenance inspections of the main rotor blade inertia screw holes, which resulted in a main rotor blade failure due to fatigue. Contributing to the accident was the pilot's inadequate preflight inspection of the main rotor blades.
- [NTSB ERA10LA190](https://openairdocs.org/ntsb/ERA10LA190.md): Robinson R22 · Miami, FL · Accident · No injuries · Limited investigation · Final report · Mar 28, 2010 · N72377 · Substantial damage
  > A loss of main rotor rpm for undetermined reasons.

Next page: https://openairdocs.org/ntsb-findings/01046210/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", '01046210'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb-findings/01046210/cases

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