# NTSB LAX87LA199: Hughes 369D, N10995, Tamunings, April 29, 1987

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Limited investigation · Final report
- Date: April 29, 1987, 10:39 local (18:39 UTC)
- Place: Tamunings
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 2 fatal
- Status: Completed, report May 26, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 25584
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX87LA199
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/25584/pdf
- Page: https://openairdocs.org/ntsb/LAX87LA199

## Sequence of events

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

- Airframe/component/system failure/malfunction, maneuvering
  - rotor system,main rotor blade - separation (cause)
  - maintenance,service of aircraft/equipment - inadequate, company maintenance personnel (contributing factor)
- Loss of control - in flight, maneuvering
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

A HUGHES 369D, OPERATED OFF OF A FISHING VESSEL, WENT OUT OF CONTROL AND CRASHED IN THE PACIFIC OCEAN, NR GUAM. THE ACCIDENT WAS WITNESSED BY THE SHIP'S CAPTAIN. HIS STATEMENT INDICATED ONE OF THE MAIN ROTOR BLADES SEPARATED IN FLT WHILE THE HELO WAS ORBITING THE SHIP AT APRX 200 FT MSL. DURING AN EARLIER FLT A VIBRATION ASSOCIATED WITH THE MAIN ROTOR SYSTEM WAS EXPERIENCED. THE DISCREPANCY WAS REFERRED TO THE A&P MECHANIC ON THE BOAT, WHO WORKED ON THE HELO FOR ABOUT ONE HOUR WITH THE PLT. THE HELO WAS THEN TEST FLOWN. THE MAIN ROTOR BLADES OF THE HUGHES 369D ARE ATTACHED TO THE MAIN ROTOR HUB WITH STAINLESS STEEL RETENTION STRAPS. THE MANUFACTURER OUTLINES A PROCEDURE DESIGNED TO HELP PREVENT MAIN ROTOR HUB COMPONENT CORROSION ON HELICOPTERS OPERATED IN MARINE ENVIRONMENTS. RECORDS MAINTAINED AT THE HELO MAINTENANCE BASED REVEALED THAT SUFFICIENT SUPPLIES WERE NOT AVAILABLE TO ACCOMPLISH THE PROCEDURE ON BOARD THE SHIP. THE ACFT WAS NOT RECOVERED.

## Aircraft

- Registration: [N10995](https://openairdocs.org/deregistered/N10995-2012-10-11), registration cancelled 2012-10-11, S/N 500721D, built 1980 (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: 721D
- Airframe hours: 5307
- Engines: ALLISON 250-C20B 375 horsepower turbo shaft
- Damage: Destroyed
- Flight: Business, Part 91
- Operator: Adriatic Sea, doing business as Fishing Vessel
- Registered owner: Apollo Enterprises Co.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, April 10, 1987, 55 hours before
- Departed: TAMUNINGS, OF

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 44; foreign; medical: unknown, unknown; seat: left; toxicology performed

## Weather

- Conditions: Visual (VMC), Day

## 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 19870429050399A](https://openairdocs.org/incident/19870429050399A), Apr 29, 1987: Hughes 369D, Tamuning, Guam, Destroyed, 2 fatal. Main rotor blade delaminated and departed. Helicopter self destructed crashed in ocean. Beleived salt water corroded

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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