SEA01LA003 · Enstrom F-28F
Enstrom F-28F · Accident: in flight collision with terrain/water during landing
From Joslin Field Magic Valley Regional Airport (TWF) to an unrecorded destination
Event
- NTSB case
- SEA01LA003
- 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
- 0
- 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
Enstrom F-28F
- Aircraft type
- Enstrom F-28
- 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
- N223RS
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Joslin Field Magic Valley Regional Airport (TWF), Twin Falls, IDTo not recorded
- 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
- Landing
- First occurrenceThe 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
- In flight collision with terrain/water
- 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
- Pilot in command › Rotor RPM, not maintained
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot reported that during a maintenance test flight to check controls, collective pitch position, throttle positioning, and rpm correlation control entering an autorotation, he entered the autorotation with low rpm. When the pilot corrected with collective pitch, the correlator over responded, resulting in an rpm overspeed. The pilot closed the throttle and increased the collective, however, the rpm dropped and the pilot had to complete the autorotation to touch down on rough terrain. So as not to have any forward speed at touch down, and fearing that the helicopter might roll over, the pilot anticipated a hard flare to stop the forward speed. Just prior to touch down, the tailrotor contacted the ground, and the tailrotor gearbox separated from the tail boom. The helicopter yawed to the right about 150 degrees before the pilot was able to level the helicopter, arrest the yaw and land without further incident.
Probable cause
The pilot's failure to maintain adequate rotor rpm. Unsuitable terrain was selected for the maintenance test flight operation.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record SEA01LA003
- Event ID
- 20001212X22251
- Case number
- SEA01LA003
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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: bd4a3c7fc95467e1b591d5b460af919adc9f4aa2532b0e9c2f3fe22957d86597; retrieved 2026-09-22T12:23:34.677Z.