# NTSB SEA90LA040: Bell 206B, N49573, Winthrop, WA, February 4, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: February 4, 1990, 11:30 local (18:30 UTC)
- Place: Winthrop, WA
- Coordinates: 48.499496, -120.329147 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=48.4995&lon=-120.3291&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 4 uninjured
- Status: Completed, report December 15, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 41166
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA90LA040
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41166/pdf
- Page: https://openairdocs.org/ntsb/SEA90LA040

## Probable cause

WATER CONTAMINATION OF THE FUEL AND THE PILOT'S INADEQUATE PREFLIGHT OF THE AIRCRAFT.  DARKNESS AND THE OBSTRUCTIONS IN THE EMERGENCY LANDING AREA WERE RELATED FACTORS.

## Analysis

DURING A LOCAL FLIGHT TO TRANSPORT SKIERS TO A MOUNTAIN, THE PILOT INITIATED A DESCENT FOR LANDING. WHEN APPROXIMATELY 30 FT AGL, DESCENT WAS TERMINATED DUE TO LOSS OF VISIBILITY FROM BLOWING SNOW. WHEN THE SNOW SETTLED, DESCENT WAS CONTINUED. JUST PRIOR TO TOUCHDOWN, VISIBILITY WAS AGAIN REDUCED AND THE PILOT LOST HIS REFERENCE POINT. THE HELICOPTER TOUCHED DOWN LEFT SKID FIRST AND IMMEDIATELY ROLLED OVER.

## Sequence of events

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

- Loss of control - on ground/water, landing - flare/touchdown
  - visual lookout - not maintained, pilot in command (cause)
  - unsuitable terrain or takeoff/landing/taxi area - selected, pilot in command (cause)
- Roll over, landing - flare/touchdown
  - terrain condition - snow covered (contributing factor)
  - terrain condition - rough/uneven (contributing factor)

## Aircraft

- Registration: [N49573](https://openairdocs.org/deregistered/N49573-2001-03-27), registration cancelled 2001-03-27, S/N 1665 (OpenAirDocs)
- Reported make and model: BELL 206B
- Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (registry code 1181511) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1665
- Airframe hours: 5309
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 135
- Registered owner: Cascade Helicopters
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, December 21, 1989, 23 hours before
- Departed: MAZAMA, WA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 44; commercial; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 3,981 total, 1,442 in this make and model, 3,484 as pilot in command, 13 in the last 90 days, 8 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 5 statute miles
- Lowest ceiling: 2,000 ft broken
- Temperature: 21 °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 19900204001539A](https://openairdocs.org/incident/19900204001539A), Feb 4, 1990: Bell 206B, Winthrop, WA, Substantial damage. Touched skid while hovering for snow covered slope landing, hidden by blowing snow, drift was recognized.

## Other investigations on N49573 (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 SEA00LA101](https://openairdocs.org/ntsb/SEA00LA101), Jun 8, 2000: Bell 206B (N49573), Bridgeport, WA, substantial damage. Probable cause: Aircraft control was not maintained. Inadequate remedial action and diverted attention were factors.

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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