# NTSB FTW88FA036: Bell 412, N3910U, Galveston, TX, December 7, 1987

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Field investigation · Final report
- Date: December 7, 1987, 13:45 local (19:45 UTC)
- Place: Galveston, TX
- Location: 29.2370° N, 94.8673° W: Placed by OpenAirDocs from NTSB’s distance and direction from SCHOLES INTL AT GALVESTON (GLS), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=29.2370&lon=-94.8673&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 2 serious
- Status: Completed, report July 3, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 22530
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW88FA036
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/22530/pdf
- Page: https://openairdocs.org/ntsb/FTW88FA036

## 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 drive system,tail rotor gearbox(90 deg) - separation (cause)
  - rotor drive system,tail rotor gearbox(90 deg) - vibration (cause)
  - rotor drive system,tail rotor gearbox(90 deg) - undetermined (cause)
- Loss of control - in flight, descent - uncontrolled
- Forced landing, descent - emergency
- Ditching, landing - flare/touchdown
  - terrain condition - water (contributing factor)

## Analysis

THE ACFT LANDED HARD IN THE GULF OF MEXICO DURING AN AUTOROTATION THAT WAS ENTERED FOLLOWING THE SEPARATION OF THE 90 DEGREE GEARBOX. THE GEARBOX (WITH TAIL ROTOR BLADES) SEPARATED DUE TO AN IMBALANCE. HOWEVER, THE GEARBOX WAS NOT RECOVERED DURING THE INVESTIGATION AND THE CAUSE OF THE IMBALANCE COULD NOT BE DETERMINED.

## Aircraft

- Registration: [N3910U](https://openairdocs.org/deregistered/N3910U-1991-04-23), registration cancelled 1991-04-23, S/N 33018 (OpenAirDocs)
- Reported make and model: BELL 412
- Registry model: [Bell 412](https://openairdocs.org/model/bell-412) (registry code 1182202) (OpenAirDocs)
- Category: Helicopter
- Serial number: 33018
- Airframe hours: 3787
- Engines: P&W PT-6T-3B 1350 horsepower turbo shaft
- Damage: Destroyed
- Flight: Other work use, Part 91
- Registered owner: Air Logistics
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, October 16, 1987, 64 hours before
- Departed: GLS
- Destination: GLS
- Airport: GLS, Scholes Fld, runway 31, 6,000 × 75 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; flight instructor, airline transport; instrument ratings: helicopter; medical: class 1, valid medical--no waivers/lim.; seat: right; flight hours: 4,806 total, 88 in this make and model, 76 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 350° at 17 knots
- Visibility: 7 statute miles
- Lowest ceiling: 1,500 ft overcast
- Temperature: 63 °F, dew point 54 °F
- Altimeter: 29.00 inHg
- Observed at: GLS, 2 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 19871207083299A](https://openairdocs.org/incident/19871207083299A), Dec 7, 1987: Bell 412, Galveston, TX, Destroyed. Tail rotor gear box and rotors separated on test flight. Unable autorotation. Spun to water impact. Bolts fatigued.

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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