FTW83LA085 · Hiller H-23D
Hiller H-23D · Accident: partial loss of engine power (mechanical failure) while maneuvering
Event
- NTSB case
- FTW83LA085
- 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
Hiller H-23D
- Aircraft type
- Hiller H-23
- 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
- N3201F
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo 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 133: Rotorcraft Ext. Load
- 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
- 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
- Partial loss of engine power (mechanical failure)
- 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 › Maintenance, service of aircraft/equipment, inadequate
- Pneumatic system › Separation
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
THE HELICOPTER MADE A HARD AUTOROTATIVE LANDING AFTER A POWER LOSS. THE PILOT STATED HE WAS HOVERING ABOUT 75 FT AGL WAITING FOR GROUND PERSONNEL TO ATTACH A LINE TO HIS EXTERNAL SLING LOAD WHEN THE ENGINE DECELERATED TO FLT IDLE AND HE COULD NOT REGAIN POWER. HE INITIATED AN AUTOROTATION BUT THE RPM HAD DECAYED AND A HARD LANDING RESULTED. AFTER THE ACCIDENT THE PILOT SAID HE FOUND THE PY ACCUMULATOR FROM THE ENGINE GOVERNOR LAYING ON THE GROUND A SHORT DISTANCE FROM THE HELICOPTER. AFTER THE ACCIDENT BEFORE FINDING THE ACCUMULATOR THE PILOT HAD STARTED THE ENGINE. HE STATED IT RAN OK BUT WOULD NOT ACCELERATE ABOVE 30 PERCENT. INVESTIGATION REVEALED THAT THE ALLISON 250 TURBINE WILL OPERATE AT ONLY ABOUT 30 PERCENT OF ITS RATED RPM WITHOUT THE PY ACCUMULATOR. THE PILOT THOUGHT THE ACCUMULATOR SHOULD BE SAFETY ATTACHED TO PRECLUDE SEPARATION FROM VIBRATION. THE PILOT SAID THAT THE SUBJECT PARTS HAD BEEN REINSTALLED ON HIS HELICOPTER AFTER REMOVAL FOR MAINTENANCE ONLY 2 AND ONE HALF HRS PRIOR TO THE CRASH.
Verbatim NTSB analysis from the NTSB dataset
Sources
NTSB record FTW83LA085
- Event ID
- 20001214X44528
- Case number
- FTW83LA085
- 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: f1f06b111a89553b439dbddfe0a59a3faa69d403973cb044b663069154f07ed9; retrieved 2026-09-23T21:22:44.459Z.