# NTSB FTW91IA143: Bell 412, N177EH, Rowan Midland, August 8, 1991

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: August 8, 1991, 10:00 local (15:00 UTC)
- Place: Rowan Midland
- Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 15 uninjured
- Status: Completed, report May 5, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 23280
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=FTW91IA143
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/23280/pdf
- Page: https://openairdocs.org/ntsb/FTW91IA143

## Probable cause

THE MECHANIC'S FAILURE TO ASSEMBLE THE TAIL ROTOR DRIVE SHAFT CORRECTLY AND THE SUBSEQUENT FAILURE OF THE TAIL ROTOR DRIVE SHAFT. A FACTOR WAS THE LACK OF INSPECTION PROCEDURES FOR OFFSHORE MAINTENANCE.

## Sequence of events

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

- Airframe/component/system failure/malfunction, takeoff - initial climb
  - maintenance,installation - improper, other maintenance personnel (cause)
  - maintenance,inspection - not performed, other maintenance personnel (contributing factor)
  - rotorcraft flight control,tail rotor control - loss,total (cause)
  - rotor drive system,tail rotor drive shaft - failure,total (cause)
  - precautionary landing - performed, pilot in command
- Forced landing, descent - emergency

## Analysis

DURING TAKEOFF FROM A MOVING VESSEL, THE PILOT LOST DIRECTIONAL CONTROL. HE ELECTED TO CONTINUE TO FLY IN AN EFFORT TO REACH AN OFFSHORE PLATFORM. AS DIRECTION CONTROL BECAME MORE UNSTABLE, THE CAPTAIN ORDERED THE FIRST OFFICER TO MAKE A WATER LANDING. FLOATS WERE INFLATED AND THE LANDING WAS MADE WITHOUT INCIDENT. ALL 15 ON BOARD WERE RECOVERED WITHOUT INCIDENT. EXAMINATION REVEALED THAT THE TAIL ROTOR DRIVE SHAFT HAD BEEN ASSEMBLED INCORRECTLY AND THAT THE QUILL ASSEMBLY HAD FAILED.

## Aircraft

- Registration: [N177EH](https://openairdocs.org/deregistered/N177EH-2004-04-16), registration cancelled 2004-04-16, S/N 33037 (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: 33037
- Engines: P&W PT6T-3B 1025 horsepower turbo shaft
- Damage: No damage
- Flight: Part 135
- Operator: Era Aviation Inc.
- Departed: NONE, WEST. CARRIBEAN, GM
- Destination: MSY, NEW ORLEANS, LA
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; airline transport; instrument ratings: helicopter; medical: class 1, valid medical--w/ waivers/lim; flight hours: 13,900 total, 8,000 in this make and model, 12,500 as pilot in command, 118 in the last 90 days, 29 in the last 30 days, 7 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 45° at 5 knots
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F

## FAA reports on this event (1)

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

- [Incident 19910808036879I](https://openairdocs.org/incident/19910808036879I), Aug 8, 1991: Bell 412, Gulf Of Mexico, LA, Minor damage. Experienced loss of tail rotor control. Landed safely in Gulf. Output coupling. Disengaged from sliding coupling.

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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