# NTSB SEA92LA030: Artic S-1B2, N71AT, Lysite, WY, December 21, 1991

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: December 21, 1991, 08:30 local (15:30 UTC)
- Place: Lysite, WY
- Coordinates: 43.25098, -107.710914 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=43.2510&lon=-107.7109&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor, 1 uninjured
- Status: Completed, report May 7, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41618
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA92LA030
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41618/pdf
- Page: https://openairdocs.org/ntsb/SEA92LA030

## Probable cause

THE PILOT'S FAILURE TO MAINTAIN CLEARANCE WITH TERRAIN.  FACTORS CONTRIBUTING TO THE ACCIDENT WERE RISING TERRAIN, DOWNDRAFTS, AND THE PILOT'S INADEQUATE COMPENSATION FOR WIND CONDITIONS.

## Analysis

THE PILOT REPORTED THAT WHILE ON AN AERIAL SURVEY OF GAME THE AIRCRAFT ENCOUNTERED A HEADWIND BUT LITTLE TURBULENCE. UPON APPROACHING A RIDGE HE EXECUTED A RIGHT TURN TO REVERSE COURSE DURING WHICH A SEVERE DOWNDRAFT WAS ENCOUNTERED. THE PILOT REPORTED APPLYING FULL POWER AND ATTEMPTING TO ESTABLISH BEST ANGLE OF CLIMB DURING WHICH THE AIRCRAFT IMPACTED THE TERRAIN.  THE PILOT REPORTED THE WINDS AT THE ACCIDENT SITE AS 20 KNOTS WITH GUSTS TO 25 KNOTS.

## Sequence of events

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

- In flight collision with terrain/water, maneuvering - turn to reverse direction
  - terrain condition - rising (contributing factor)
  - weather condition - downdraft (contributing factor)
  - clearance - not maintained, pilot in command (cause)
  - compensation for wind conditions - inadequate, pilot in command (contributing factor)

## Aircraft

- Registration: [N71AT](https://openairdocs.org/deregistered/N71AT-2013-03-25), registration cancelled 2013-03-25, S/N 1022, built 1982 (OpenAirDocs)
- Reported make and model: Artic Aircraft Corp. S-1B2
- Registry model: [Arctic S-1B2](https://openairdocs.org/model/arctic-s-1b2) (registry code 0790208) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 1022
- Airframe hours: 3265
- Engines: LYCOMING O-320-B2B 160 horsepower reciprocating
- Damage: Substantial damage
- Flight: Aerial observation, Part 91
- Operator: Sky Aviation Corporation
- Registered owner: Sky Aviation Corporation
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, September 25, 1991, 67 hours before
- Departed: WRL, WORLAND, WY
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; airline transport, flight instructor; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, valid medical--no waivers/lim.; seat: front; flight hours: 7,400 total, 2,000 in this make and model, 7,340 as pilot in command, 210 in the last 90 days, 60 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 60 statute miles
- Lowest ceiling: none
- Temperature: 7 °F, dew point 1 °F
- Altimeter: 30.00 inHg
- Observed at: WRL, 29 nm away

## 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 19911221060529A](https://openairdocs.org/incident/19911221060529A), Dec 21, 1991: Arctic S1B2, Lysite, WY, Substantial damage. On aerial game survey encountered a severe downdraft. Began turn away from ridge. Unable recover. Impact deep snow.

## Other investigations on N71AT (2)

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 DEN02GA097](https://openairdocs.org/ntsb/DEN02GA097), Aug 16, 2002: Arctic S-1B2 (N71AT), Meeteetse, WY, destroyed, 1 fatal. Probable cause: the pilot's failure to maintain adequate airspeed, which resulted in an inadvertent stall/spin. A contributing factor was the intentional low pass/slow flight maneuver.
- [NTSB FTW98LA065](https://openairdocs.org/ntsb/FTW98LA065), Dec 6, 1997: Artic S-1B2 (N71AT), Worland, WY, substantial damage. Probable cause: loss of engine power for undetermined reason(s). A related factor was the rough and uneven terrain on which the forced landing was made.

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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