CEN19LA240 · Robinson R44 II
NE IA Helicopters Robinson R44 II · Accident: system/component malfunction/failure (non-power) while maneuvering
From Blair, NE to Blair, NE
Event
- NTSB case
- CEN19LA240
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Robinson R44 II
- Aircraft type
- Robinson R44
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N7508Z
- Operator
- NE IA Helicopters
- Onboard fatalities
- Unknown
- Route
- From Blair, NETo Blair, NE
- Aircraft age
- About 14 years (built 2005)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 137: Agricultural
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Maneuvering · low-altitude flying
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- System/component malfunction/failure (non-power)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Aircraft › Aircraft propeller/rotor
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
After completing a spray pass during a helicopter aerial application flight, the pilot initiated a climb over trees to head south. The pilot reported that, at the top of the climb, he noticed that the engine rpm was beyond "max limitations" and that the main rotor rpm was in the green range. The pilot initiated a right pedal turn to the north and decreased the engine throttle to lower the engine rpm. The engine rpm remained at the upper limit, but the main rotor rpm decreased. The pilot then attempted to correct the main rotor rpm by increasing the throttle; however, the main rotor rpm fluctuated and then continued to decrease. Unable to control and maintain the main rotor rpm, the pilot performed a forced landing to a field with sloped terrain, during which the main rotor blades impacted terrain. The helicopter sustained substantial damage to the main rotor blades and tailboom. Postaccident examination of the upper and lower actuator support bearing brackets revealed they were separated from the scroll, and evidence of fretting and rub marks was noted between the brackets and scroll walls. In addition, elongated rivet holes were observed on the scroll wall, and the associated rivets were sheared. Torque paint was noted on the outboard rivets. It is likely that the bracket supporting the lower actuator bearing became loose and sheared the rivets, which allowed the actuator bearing to shift and led to a subsequent misalignment of the clutch actuator. The misalignment of the clutch actuator resulted in the loss of belt tension between the engine and main rotor drive system. The reason for the loose bracket and sheared rivets could not be determined due to damage. A manufacturer service bulletin required an inspection of the brackets for evidence of fretting or looseness, and that was accomplished about 169 flight hours before the accident. The compliance procedure, which was to occur at the next 100-hour or annual inspection, was to visually inspect the brackets and attaching rivets for evidence of fretting or looseness and, on the lower bracket, to apply torque seal in a vertical stripe across both outboard rivets to lower scroll to facilitate future inspections. It is likely that the wear was not apparent at the time of the inspection.
Probable cause
The failure of the lower actuator bearing support bracket, which resulted in the misalignment of the clutch actuator, the loss of belt tension on the main rotor drive system, and the subsequent forced landing on sloped terrain.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN19LA240
- Event ID
- 20190728X32331
- Case number
- CEN19LA240
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: cda60b0d669277579e36341147164f2a55c93452864a374f114531e4aa3e8917; retrieved 2026-09-16T09:35:36.072Z.