# NTSB FTW83LA085: Hiller H-23D, N3201F, Humble, TX, September 12, 1983

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 12, 1983, 09:30 local (15:30 UTC)
- Place: Humble, TX
- Coordinates: 29.989635, -95.260681 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=29.9896&lon=-95.2607&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 20790
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW83LA085
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/20790/pdf
- Page: https://openairdocs.org/ntsb/FTW83LA085

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of engine power(partial) - mech failure/malf, hover
  - pneumatic system - separation (cause)
  - maintenance,service of aircraft/equipment - inadequate, pilot in command (cause)
- Forced landing, landing - flare/touchdown
  - autorotation - initiated, pilot in command (contributing factor)
- Hard landing, landing - flare/touchdown

## Analysis

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.

## Aircraft

- Registration: N3201F (not matched to a registry record)
- Reported make and model: HILLER H-23D
- Category: Helicopter
- Serial number: 952
- Engines: ALLISON 250-C20 turbo shaft
- Damage: Substantial damage
- Flight: Other work use, Part 133
- Registered owner: Hi Line Helicopters Inc.
- Airworthiness certificate: Standard, Normal

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 33; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; flight hours: 5,843 total, 3,115 in this make and model, 10 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 25 statute miles
- Lowest ceiling: none
- Temperature: 64 °F
- Altimeter: 29.00 inHg

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.