CEN11FA422 · Robinson R22 BETA
Robinson R22 BETA · Accident: mast bumping en route
From Taylor Municipal Airport (KT74) to Luling, TX
Event
- NTSB case
- CEN11FA422
- 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
- 1 · 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 R22 BETA
- Aircraft type
- Robinson R22
- 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
- N7779M
- Operator
- Don S. Arsenault · private individual
- Onboard fatalities
- Unknown
- Route
- From Taylor Municipal Airport (KT74), Taylor, TXTo Luling, TX
- Aircraft age
- Not recorded
- 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 91: General Aviation
- 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
- En route · cruise
- 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
- Mast bumping
- 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 from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The helicopter was flying across a river when witnesses heard a loud "pop" or "bang" and saw something fall from the helicopter into the river. They heard the helicopter crash, saw smoke, and ran to the crash site. One main rotor blade was found approximately 780 feet from the wreckage. The other main rotor blade was found approximately 975 feet from the wreckage in the opposite direction. Both blades had separated from the main rotor hub at their coning hinges. All components of the helicopter were accounted for with the exception of portions of both coning bolts. The investigation was unable to locate the object observed falling from the helicopter or determine what it was. Examination of the rotor head components, including the recovered portions of the coning bolts, revealed fracture features consistent with overload failure and mechanical damage indicative of mast bumping (contact between the main rotor blades and the mast). The main rotor blade pitch links and attaching hardware displayed compression buckling and bending overload features consistent with an out-of-control main rotor that had diverged from its normal plane of rotation. The helicopter manufacturer reported that the damage signatures were consistent with both low-G mast bumping and low rotor rpm rotor stall. Low-G mast bumping is a phenomenon specific to two-bladed teetering rotor systems in which the rotor disc becomes unloaded, typically due to a cyclic pushover. Low rotor rpm rotor stall is a different phenomenon in which the main rotor blades experience an aerodynamic stall due to low rotor rpm caused either by the pilot raising the collective too much or by a loss of engine power followed by the pilot lowering the collective too slowly. Rotor blade stall can lead to mast bumping. The pilot’s control inputs leading up to the event are unknown, and, therefore, the reason for the main rotor divergence could not be determined.
Probable cause
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.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN11FA422
- Event ID
- 20110627X51003
- Case number
- CEN11FA422
- 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, coordinates. 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: cf4447deae407798bf53a97733d10746f56667f6a56442e068100b9277c7ae5f; retrieved 2026-09-13T21:29:07.022Z.