WPR15IA080 · Robinson Helicopter R22 BETA II
Robinson Helicopter R22 BETA II · Incident: system/component malfunction/failure (non-power) on approach
From Mesa Gateway Airport (IWA) to Mesa Gateway Airport (IWA)
Event
- NTSB case
- WPR15IA080
- 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
- Incident
- 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 Helicopter R22 BETA II
- 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
- N7041X
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Mesa Gateway Airport (IWA), Chandler, AZTo Mesa Gateway Airport (IWA), Chandler, AZ
- Aircraft age
- Built the same year (2014)
- 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
- Approach · VFR pattern downwind
- 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
- None
Cause areas
- Aircraft › Aircraft power plant
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The private pilot reported that he was practicing for the commercial pilot helicopter examination and was operating in the airport traffic pattern. The pilot stated that, while entering downwind, he climbed the helicopter to 1,900 ft and was accelerating it to 75 knots when he felt an "abnormal vibration" and smelled "something…burning." The low rotor rpm light illuminated, and the low rotor rpm horn sounded. He subsequently entered an autorotation, made an emergency call, and landed successfully off the runway on dirt.
Postaccident examination of the helicopter revealed that the fanshaft had fractured circumferentially; the helicopter had a total time of 337 hours. Examination of the fanshaft revealed a crack in the fanwheel's base, which had beach marks that ran from the fanshaft's bearing surface out and down to the mounting surface, consistent with fatigue. The roller bearings and the races bearing surfaces had minor surface damage. The bearings and races were cut away from the fan shaft, which revealed a v-shaped fracture surface that had two cracks emanating from it. This area had sustained damage from the two halves contacting each other with every rotation of the crankshaft, and some material was missing. The fracture origin could not be determined due to the damage. The only anomaly identified during the examination was that the fanwheel was out of balance; however, this likely resulted from the fanshaft failure.
Probable cause
The failure of the fanshaft due to fatigue.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR15IA080
- Event ID
- 20150108X11648
- Case number
- WPR15IA080
- 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: local date, investigation status, damage. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2014-12-30.
- API snapshot SHA-256: e32489e9a45a1b8142319577c3a61b3597a38c613760284a94180e47aa653d38; retrieved 2026-09-16T02:01:18.929Z.