# NTSB ANC92LA090: McDonnell Douglas MD-500D, N8395F, Polk Inlet, AK, June 10, 1992

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: June 10, 1992, 11:30 local (19:30 UTC)
- Place: Polk Inlet, AK
- Coordinates: 55.610553, -131.580108 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=55.6106&lon=-131.5801&mi=10
- Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 4 uninjured
- Status: Completed, report September 14, 1993
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5741
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC92LA090
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5741/pdf
- Page: https://openairdocs.org/ntsb/ANC92LA090

## Probable cause

THE PILOT'S FAILURE TO FOLLOW PROPER PROCEDURE AND THE COMPANY'S INADEQUATE PROCEDURES AND DIRECTIVES. A FACTOR WAS THE UNEVEN TERRAIN.

## Sequence of events

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

- Dragged wing,rotor,pod,float or tail/skid, standing - idling rotors
  - terrain condition - rough/uneven (contributing factor)
  - procedures/directives - not followed, pilot in command (cause)
- Airframe/component/system failure/malfunction, descent - normal
  - rotor drive system,tail rotor drive shaft - sheared (cause)
  - procedures/directives - inadequate, company/operator management (cause)
- Ditching, descent - emergency
  - terrain condition - water

## Analysis

THE PILOT LANDED THE HELICOPTER ON UNSTABLE TERRAIN AND WHEN HE AND THE OTHER FRONT SEAT PASSENGER EXITED BEFORE THE REAR PASSENGERS THE HELICOPTER ROCKED BACKWARDS AND THE TAILROTOR STRUCK THE MUSKEG WHILE THE MAIN ROTOR WAS STILL TURNING SLOWLY.  THE PILOT EXAMINED THE DRIVE TRAIN FOR DAMAGE AND FOUND NONE AND ELECTED TO FLY BACK TO HIS BASE OF OPERATIONS.  DURING THE FLIGHT THE TAIL ROTOR DRIVE SHAFT SEPARATED AND HE LOST TAIL ROTOR THRUST.  THE PILOT EXECUTED A LANDING IN THE WATER. ACCORDING TO THE PILOT AND THE CHIEF PILOT, THERE IS NO INFORMATION IN THE COMPANY OPERATIONS MANUAL OR THE TRAINING MANUAL INDICATING WHAT ACTION HE SHOULD TAKE AFTER A BLADE STRIKE HAS OCCURRED.  ACCORDING TO THE CHIEF PILOT THE PILOT DID NOT FOLLOW THE VERBAL PROCEDURE WHICH REQUIRES HIM TO REMAIN INSIDE THE HELICOPTER UNTIL THE BLADES STOP ROTATING.

## Aircraft

- Registration: [N8395F](https://openairdocs.org/deregistered/N8395F-2018-02-20), registration cancelled 2018-02-20, S/N 880339D, built 1978 (OpenAirDocs)
- Reported make and model: McDonnell Douglas MD-500D
- Registry model: [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d) (registry code 4470706) (OpenAirDocs)
- Registry engine: [Allison 250 SER 400HP](https://openairdocs.org/engine/allison-250-ser-400hp) (registry code 03013, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 880339D
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 135
- Operator: Cri Helicopters
- Registered owner: C And I Corp
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, January 2, 2000
- Departed: MOUNTAIN TOP, AK

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 33; airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane, helicopter; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 4,300 total, 110 in this make and model, 3,895 as pilot in command

## Weather

- Conditions: Visual (VMC), Day
- Wind: 90° at 10 knots
- Visibility: 25 statute miles
- Lowest ceiling: none
- Temperature: 55 °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).

- [Accident 19920610019429A](https://openairdocs.org/incident/19920610019429A), Jun 10, 1992: Hughes 369D, Polk Inlet, AK, Substantial damage. Tail rotor hit tundra, rocked after landing. Looked ok,took off for base. Lost tail rotor control. Landed in water.

## Other investigations on N8395F (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 LAX96FA076](https://openairdocs.org/ntsb/LAX96FA076), Dec 20, 1995: Hughes 369D (N8395F), Feather Falls, CA, destroyed, 1 fatal. Probable cause: the pilot's failure to jettison his external load after it came in contact with trees and terrain. The pilot's failure to maintain altitude/clearance above trees and hilly terrain was a related…

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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