CEN14LA401 · Mosquito XE
Mosquito XE · Accident: part(s) separation from aircraft while maneuvering
From Wittman Regional Airport (OSH) to Wittman Regional Airport (OSH)
Event
- NTSB case
- CEN14LA401
- 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
Mosquito XE
- Aircraft type
- Mosquito XE
- 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
- CF-HEZ
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Wittman Regional Airport (OSH), Oshkosh, WITo Wittman Regional Airport (OSH), Oshkosh, WI
- Aircraft age
- About 12 years (built 2002)
- 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
- Maneuvering
- 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
- Part(s) separation from aircraft
- 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
Just after takeoff, the experimental, amateur-built helicopter started to rotate and then impacted the ground in a level attitude, which resulted in substantial damage to the helicopter. Examination revealed that one tail rotor blade had separated from the tail rotor and gearbox assembly and that the blade had separated cleanly from the assembly; neither the collar nor the pins used to secure the blade were located. The pilot reported that he had been testing this tail rotor design for 4 years. A tension/torsion strap and two steel pins were used to retain the blade. The strap was not completely restricted from movement, and, over time, movement and wear resulted in the failure of the retaining assembly. The tail rotor assembly was a unique design and was not used in any other application.
Probable cause
The failure of the retaining assembly on the tail rotor blade, which resulted in the separation of the blade and the subsequent loss of helicopter control.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN14LA401
- Event ID
- 20140802X50827
- Case number
- CEN14LA401
- 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: 39931d42dc6e09adaf399c0c862045022b24a955e2481d4e7c3fb2c0c7aeb090; retrieved 2026-09-16T01:35:39.209Z.