# NTSB FTW93LA047: Hiller UH12B, N1048P, Justin, TX, December 2, 1992

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: December 2, 1992, 17:00 local (23:00 UTC)
- Place: Justin, TX
- Coordinates: 33.080005, -97.290283 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=33.0800&lon=-97.2903&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report June 30, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 18625
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW93LA047
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18625/pdf
- Page: https://openairdocs.org/ntsb/FTW93LA047

## Probable cause

FAILURE OF THE MAIN ROTOR SYSTEM FOR UNDETERMINED REASONS. A FACTOR WAS THE LACK OF SUITABLE TERRAIN AT THE PILOT'S DISPOSAL.

## Sequence of events

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

- Airframe/component/system failure/malfunction, approach - vfr pattern - final approach
  - rotor system - vibration
  - reason for occurrence undetermined (cause)
  - precautionary landing - initiated, pilot in command
  - terrain condition - none suitable (contributing factor)
- In flight collision with terrain/water, descent - emergency
  - landing gear,skid assembly - collapsed
- Loss of control - on ground/water, landing - flare/touchdown
  - object - fence post

## Analysis

THE COMMERCIAL PILOT REPORTED THAT THE HELICOPTER DEVELOPED A SEVERE VERTICAL VIBRATION WHILE ON HIS TURN TO FINAL APPROACH WHILE ON A TEST FLIGHT FOR COMPLETION OF AN ANNUAL INSPECTION. THE PILOT ELECTED TO MAKE AN IMMEDIATE PRECAUTIONARY LANDING TO AN OPEN FIELD SHORT OF HIS INTENDED LANDING POINT. WHILE ON AN EXAGGERATED FLARE TO AVOID IMPACTING LARGE BALES OF HAY, THE TAIL ROTOR STRUCK THE GROUND AND THE MAIN ROTOR BLADES IMPACTED THE TAILBOOM. THE LEFT LANDING GEAR SKID FOLDED PRIOR TO THE HELICOPTER COMING TO A STOP. THE SOURCE OF THE VERTICAL VIBRATION WAS NOT IDENTIFIED.

## Aircraft

- Registration: [N1048P](https://openairdocs.org/aircraft/N1048P), registered now, S/N 635 (OpenAirDocs)
- Reported make and model: HILLER UH12B
- Registry model: [Hiller-Tri-Plex Ind.Inc. UH-12B](https://openairdocs.org/model/hiller-tri-plex-ind-inc-uh-12b) (registry code 4360801) (OpenAirDocs)
- Registry engine: [Franklin 6V-335 series](https://openairdocs.org/engine/franklin-6v-335-series) (registry code 27039, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 635
- Engines: FRANKLIN VO-335-B 210 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Clark, Landis E., doing business as Clark'S Aircraft Sales
- Registered owner: Clark, Landis E.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, December 1, 1992, 1 hours before
- Departed: 3TX6
- Destination: 3TX6
- Airport: 3TX6, Clark'S Airport, runway 35, 1,800 × 22 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 59; commercial, flight instructor; airplane ratings: single-engine sea, multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: center; flight hours: 10,822 total, 15 in this make and model, 10 in the last 90 days, 1 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 40° at 12 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 52 °F, dew point 21 °F
- Altimeter: 30.00 inHg
- Observed at: AFW, 10 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19921202048999A](https://openairdocs.org/incident/19921202048999A), Dec 2, 1992: Hiller UH12B, Justin, TX, Substantial damage. Reported severe vibration. Made autorotation to hay field. Overrotated on flare. Tail hit. Rotors chopped tailboom.

## Other investigations on N1048P (1)

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.

- [NTSB LAX85LA309](https://openairdocs.org/ntsb/LAX85LA309), Jul 7, 1985: Hiller UH-12B (N1048P), Durham, CA, substantial damage

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.