CEN19LA065 · Robinson R44 II
Robinson R44 II · Accident: loss of control in flight during initial climb
From Garner Field (UVA) to Garner Field (UVA)
Event
- NTSB case
- CEN19LA065
- 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
- N484AB
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Garner Field (UVA), Uvalde, TXTo Garner Field (UVA), Uvalde, TX
- Aircraft age
- About 13 years (built 2006)
- 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
- Initial climb
- 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
- Loss of control in flight
- 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 oper/perf/capability
- Aircraft › Aircraft propeller/rotor
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The student pilot and flight instructor were conducting a local, instructional flight. The instructor reported that, as the student was transitioning the helicopter through effective translational lift about 40 knots airspeed, he raised the collective to increase the available power to the takeoff power setting. Shortly thereafter, he heard a loud "pop/bang sound," which was followed by an uncommanded right yaw and severe vibrations. Due to the low altitude and airspeed, the instructor immediately took the flight controls and initiated an autorotation. Upon touchdown, the helicopter tilted forward, and the instructor applied aft cyclic to correct; however, the main rotor blades contacted the tailboom, which resulted in the tailboom partially separating from the helicopter.
During postaccident examination of the helicopter, the clutch assembly lubricant was drained, and metallic debris was found in the strainer. Disassembly of the clutch assembly revealed galling of the sprags and the corresponding sprag contact surfaces on the clutch shaft and hub. It is likely that the excessive galling resulted in the sprag clutch slipping, which produced the uncommanded right yaw and led to the student's and instructor's inability to maintain helicopter control.
Probable cause
The slipping of the sprag clutch due to galling of the sprags and corresponding sprag contact surfaces within the clutch assembly, which rendered the helicopter uncontrollable.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN19LA065
- Event ID
- 20190108X54945
- Case number
- CEN19LA065
- 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: 15d1b50085986a706ddafd0aaa28b1d9cd4e9927ecf4f83e7f80f64136d98fba; retrieved 2026-09-16T08:32:16.532Z.