# NTSB SEA91LA023: Hughes 369D, N1106Z, Mulina, OR, November 26, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: November 26, 1990, 07:30 local (15:30 UTC)
- Place: Mulina, OR
- Coordinates: 45.199226, -122.54071 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=45.1992&lon=-122.5407&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report September 28, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 41367
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA91LA023
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41367/pdf
- Page: https://openairdocs.org/ntsb/SEA91LA023

## Probable cause

IN-FLIGHT COLLISION WITH A REBOUNDING LONG-LINE, WHICH CAUSED MAIN-ROTOR RPM DECAY AND TAIL-BOOM SEPARATION, COMPROMISING THE PILOT'S ABILITY TO SUCCESSFULLY ACCOMPLISH AN ATTEMPTED AUTOROTATION.

## Sequence of events

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

- In flight collision with object, maneuvering
  - object - other (contributing factor)
  - rotor system,main rotor blade - disabled (cause)
- Forced landing, descent - emergency
  - misc rotorcraft,tail cone - separation (contributing factor)
  - autorotation - attempted, pilot in command

## Analysis

THE HUGHES 369D HELICOPTER CRASHED WHILE CONDUCTING CHRISTMAS TREE EXTERNAL-LOAD OPERATIONS WHEN A CHOKER ATTACHED TO A LONG- LINE EXTERNAL HOOK SNAGGED ON AN UNIDENTIFIED OBJECT AND SNAPPED THE REMOTE HOOK INTO THE MAIN ROTOR SYSTEM. ACCORDING TO THE PILOT, A POWER-ON AUTOROTATION WAS ATTEMPTED, BUT DUE TO LOW ROTOR RPM, THE MAIN BLADES CHOPPED OFF THE TAIL BOOM.

## Aircraft

- Registration: [N1106Z](https://openairdocs.org/aircraft/N1106Z), registered now, S/N 210900D, built 1981 (OpenAirDocs)
- Reported make and model: HUGHES 369D
- Registry model: [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d) (registry code 4470706) (OpenAirDocs)
- Registry engine: [Allison 250 SER 250HP](https://openairdocs.org/engine/allison-250-ser-250hp) (registry code 03002, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 210900D
- Engines: ALLISON 250-C20 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Other work use, Part 133
- Operator: Temesco Helicopters Inc
- Registered owner: Unknown
- Departed: NONE
- Destination: NONE
- Airport: None

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; airline transport; airplane ratings: single-engine sea, multi-engine land, single-engine land, multi-engine sea; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; flight hours: 9,700 total, 2,700 in this make and model, 8,340 as pilot in command, 162 in the last 90 days, 61 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 10 statute miles
- Lowest ceiling: 2,500 ft overcast
- 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).

- [Accident 19901126051969A](https://openairdocs.org/incident/19901126051969A), Nov 26, 1990: Hughes 369D, Mulina, OR, Substantial damage. Loose choker line from prior slipped load snagged and flipped hook into rotors. Hard landing chopped tail boom.

## Other investigations on N1106Z (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 ANC83LA138](https://openairdocs.org/ntsb/ANC83LA138), Aug 5, 1983: Hughes 369D (N1106Z), Mcgrath, AK, 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.

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