CEN21LA124 · Hiller UH12C
Hiller UH12C · Accident: dynamic rollover while maneuvering
Event
- NTSB case
- CEN21LA124
- 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
- Event fatalities
- Unknown
- 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
Hiller UH12C
- Aircraft type
- Hiller UH12
- 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
- N552DR
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- Aircraft age
- About 65 years (built 1956)
- 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 · hover
- 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
- Dynamic rollover
- 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
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot stated that shortly after liftoff, the helicopter drifted left, and the left landing skid contacted the ground, which caused a dynamic rollover onto the helicopter’s left side. The helicopter sustained substantial damage to the main rotor system, transmission structural support, and the tail rotor drive shaft. The pilot stated that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation. Additionally, the pilot stated that he had not flown the helicopter during the previous 2 months, and that the accident might have been prevented had he flown the helicopter more frequently.
Probable cause
The pilot’s failure to maintain control of the helicopter shortly after liftoff into a hover, which resulted in a dynamic rollover when the left landing skid contacted the ground.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN21LA124
- Event ID
- 20210208102612
- Case number
- CEN21LA124
- 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, cause areas. 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: 5404a8cd6988de1e481181bc2e2cad27bbccaa8bfc8514dd5a60fa72289c96b0; retrieved 2026-09-16T13:37:17.671Z.