# NTSB FTW90DPA05: Gyroflug SC01B160, N3412L, Mineral Wells, TX, June 10, 1990

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: June 10, 1990, 08:15 local (13:15 UTC)
- Place: Mineral Wells, TX
- Coordinates: 32.82085, -98.070945 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=32.8209&lon=-98.0709&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report December 14, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 22931
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW90DPA05
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/22931/pdf
- Page: https://openairdocs.org/ntsb/FTW90DPA05

## Probable cause

TOTAL PROPELLER BLADE RETENTION FAILURE, THE RESULTANT SEPARATION OF ONE PROPELLER BLADE, AND THE IMPROPER INSTALLATION OF THE PROPELLER BY UNKNOWN MAINTENANCE PERSONNEL.

## 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 - base leg/base to final
  - propeller system/accessories,prop blade retention - failure,total (cause)
  - propeller system/accessories,blade - separation (cause)
  - maintenance,installation - improper, other maintenance personnel (cause)
  - remedial action - attempted, pilot in command
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE AIRPLANE HAD BEEN MODIFIED TO BE FLOWN EITHER REMOTELY OR BY THE PILOT. TAKEOFF AND INITIAL CLIMB WERE PERFORMED BY REMOTE CONTROL AND CONTROL WAS TRANSFERRED TO THE PILOT TO POSITION FOR A REMOTE CONTROL LANDING. ANGLE OF BANK INCREASED PAST 90 DEGREES IN A NOSE HIGH ATTITUDE AT ABOUT 425 FEET AGL; THE PILOT TRANSMITTED THAT HE WAS 'GOING DOWN' SHORTLY BEFORE IMPACT. ONE OF THE THREE WOODEN PROPELLER BLADES SEPARATED FROM THE HUB AND WAS FOUND 1/4 MILE FROM THE MAIN WRECKAGE. THE BLADE WAS ATTACHED TO THE HUB PRIMARILY BY 5 LAG SCREWS. THREADS IN THE WOOD BUTT OF THE SEPARATED BLADE WERE STRIPPED. THE 5 SCREWS REMAINED IN PLACE. LAG SCREWS IN THE REMAINING 2 BLADES WERE FOUND UNDERTORQUED. SEVERAL DISCREPANCIES WERE NOTED REGARDING SPECIFICATIONS FOR PROPELLER BLADE ROOT AND SIZE, TOLERANCES, AND LAG SCREWS.

## Aircraft

- Registration: [N3412L](https://openairdocs.org/deregistered/N3412L-1990-12-07), registration cancelled 1990-12-07, S/N S-46, built 1988 (OpenAirDocs)
- Reported make and model: GYROFLUG SC01B160
- Registry model: [Gyroflug SC 01 B 160](https://openairdocs.org/model/gyroflug-sc-01-b-160) (registry code 3581001) (OpenAirDocs)
- Category: Airplane
- Serial number: S-46
- Airframe hours: 139
- Engines: LYCOMING O-320-D1A 160 horsepower reciprocating
- Damage: Destroyed
- Flight: Other work use, Part 91
- Registered owner: Litton Applied Technology
- Airworthiness certificate: Special, Experimental (Special)
- Last inspection: Annual, January 30, 1990, 90 hours before
- Airport: MWL, Municipal

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; flight engineer, airline transport, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: front; toxicology performed; flight hours: 5,354 total, 20 in this make and model, 4,699 as pilot in command

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 75 °F, dew point 70 °F
- Observed at: MWL, 4 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 19900610019339A](https://openairdocs.org/incident/19900610019339A), Jun 10, 1990: Amtr SC01B160, Mineral Wells, TX, Destroyed, 1 fatal. Lost control and crashed after prop blade separated on approach. Blade stripped from undertorqued undersized bolts.

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.

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