# NTSB SEA90GA180: Bell 204B, Keller, WA, September 12, 1990

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Final report
- Date: September 11, 1990, 17:46 local (Sep 12, 1990, 00:46 UTC)
- Place: Keller, WA
- Coordinates: 48.100849, -118.710487 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=48.1008&lon=-118.7105&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed, report July 2, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41131
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA90GA180
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41131/pdf
- Page: https://openairdocs.org/ntsb/SEA90GA180

## Probable cause

THE TOTAL LOSS OF ENGINE POWER DUE TO TURBINE BLADE SEPARATION WHILE THE PILOT WAS OPERATING IN THE AIRCRAFT AT A GROSS WEIGHT THAT EXCEEDED PERFORMANCE SPECIFICATIONS FOR EXISTING METEOROLOGICAL CONDITIONS. FACTORS INCLUDE THE FAILURE OR INABILITY TO JETTISON THE EXTERNAL LOAD, THE USE OF AN IMPROPER CINCH STRAP, AND AN IMPROPERLY ASSEMBLED AND MAINTAINED WIRING CONNECTOR.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, cruise
  - aircraft weight and balance - exceeded (cause)
  - misc eqpt/furnishings - improper (cause)
  - maintenance,replacement - improper, company maintenance personnel (cause)
  - turbine assembly,turbine blade - separation (cause)
  - load jettison - not possible, pilot in command (contributing factor)
- Forced landing, descent - uncontrolled
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE PILOT WAS CONDUCTING FIRE FIGHTING MULTIPLE WATER DROPS USING AN EXTERNAL LOAD 'BAMBI BUCKET'. EARLY THAT DAY THE BUCKET'S CINCH STRAP HAD BEEN REPLACED. ON THIS DROP THE PILOT RADIOED THAT HE WAS HEAVY...3600 POUNDS. A PUFF OF SMOKE WAS OBSERVED, AND THE HELICOPTER CRASHED. INVESTIGATION REVEALED THAT A LOSS OF POWER HAD OCCURRED DUE TO THE LOSS OF ALL 2ND TURBINE ROTOR BLADES, PRECIPITATED BY A STRESS RUPTURE FAILURE OF 3 CONSECUTIVE BLADES INDUCED BY HIGH OPERATING TEMPERATURES. THE CINCH STRAP WAS BOUGHT AT A HARDWARE OR SPORTING GOODS STORE - IT WAS NOT THAT PROVIDED BY THE MANUFACTURER. DISASSEMBLY OF THE BUCKET CONTROL HEAD WIRING ASSEMBLY REVEALED EVIDENCE TO SUPPORT INTERMITTENT OPERATION.

## Aircraft

- Registration: CGKQH (not matched to a registry record)
- Reported make and model: BELL 204B
- Category: Helicopter
- Serial number: 2006
- Airframe hours: 18980
- Engines: LYCOMING T53-11A 1100 horsepower turbo shaft
- Damage: Destroyed
- Fire: On-Ground
- Flight: Public aircraft, Part 91
- Operator: Cazn-Arc Helicopters, Ltd
- Registered owner: Can-Arc Helicopters Ltd
- Last inspection: 100 hour, August 24, 1990, 16 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 53; commercial; medical: class 1, valid medical--w/ waivers/lim; seat: right; toxicology performed; flight hours: 6,682 total, 1,900 in this make and model, 6,600 as pilot in command, 182 in the last 90 days, 32 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 225° at 5 knots, gusting 9
- Lowest ceiling: none
- Temperature: 90 °F, dew point 70 °F
- Observed at: 1 nm away

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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