# NTSB ANC90LA045: Aerospatiale SA-315B, N37903, Trading Bay, AK, April 6, 1990

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: April 5, 1990, 17:55 local (Apr 6, 1990, 01:55 UTC)
- Place: Trading Bay, AK
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 4 minor, 1 uninjured
- Status: Completed, report September 30, 1991
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5346
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC90LA045
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5346/pdf
- Page: https://openairdocs.org/ntsb/ANC90LA045

## Probable cause

THE PILOT'S INADVERTENT FLIGHT INTO INSTRUMENT METEOROLOGICAL CONDITIONS (IMC).   FACTORS RELATED TO THE ACCIDENT WERE:  SNOW COVERED TERRAIN, ADVERSE WEATHER CONDITIONS,  AND SPATIAL DISORIENTATION OF THE PILOT, DUE TO LACK OF VISUAL CURE DURING THE LANDING.

## Sequence of events

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

- In flight encounter with weather, cruise
  - terrain condition - snow covered (contributing factor)
  - weather condition - snow (contributing factor)
  - weather condition - high wind (contributing factor)
  - weather condition - whiteout (contributing factor)
  - vfr flight into imc - inadvertent, pilot in command (cause)
- In flight collision with terrain/water, landing - flare/touchdown
  - precautionary landing - initiated, pilot in command
  - flare - not possible, pilot in command
  - visual/aural perception, pilot in command (contributing factor)
  - spatial disorientation, pilot in command (contributing factor)

## Analysis

THE PLT RPRTD THAT WHEN HE TOOK OFF, THERE WAS 1-1/2 TO 2 MI VIS WITH LIGHT SNOW.  ABOUT 5 MIN LATER, HE ENCOUNTERED WHITEOUT CONDITIONS & INITIATED A LANDING.  HOWEVER, THE HELICOPTER TOUCHDOWN HARD & THE MAIN ROTOR BLADES CONTACTED THE TAIL BOOM, WHICH RESULTED IN EXTENSIVE DAMAGE.

## Aircraft

- Registration: [N37903](https://openairdocs.org/deregistered/N37903-2007-06-08), registration cancelled 2007-06-08, S/N 2565, built 1979 (OpenAirDocs)
- Reported make and model: AEROSPATIALE SA-315B
- Registry model: [Aerospatiale SA315B](https://openairdocs.org/model/aerospatiale-sa315b) (registry code 8680615) (OpenAirDocs)
- Registry engine: [Turbomeca ARTOUSTEIIIB](https://openairdocs.org/engine/turbomeca-artousteiiib) (registry code 60003, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 2565
- Airframe hours: 5457
- Engines: TURBOMECA ARTOUSTE IIIB 550 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Business, Part 91
- Operator: Nthrn Geophysical Of America
- Registered owner: Prudential Capitol Group Co.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, April 2, 1990, 22 hours before
- Departed: DRIFT RIVER, AK
- Destination: GRANITE POINT, AK

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; commercial; airplane ratings: single-engine land, multi-engine land; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 15,779 total, 4,000 in this make and model, 15,579 as pilot in command, 264 in the last 90 days, 102 in the last 30 days, 6 in the last 24 hours

## Weather

- Conditions: Instrument (IMC), Day
- Wind: 350° at 25 knots
- Visibility: 1 statute miles
- Temperature: 32 °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 19900405007669A](https://openairdocs.org/incident/19900405007669A), Apr 5, 1990: Aerosp SA315B, Trading Bay, AK, Substantial damage. Encountered whiteout conditions. Got vertigo. Elected to land in snow. Impacted and main rotors chopped tail boom.

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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