# NTSB SEA91LA097: Grumman AA-1B, N1412R, Douglas, WY, May 2, 1991

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Limited investigation · Final report
- Date: May 2, 1991, 14:30 local (20:30 UTC)
- Place: Douglas, WY
- Location: 42.7548° N, 105.3978° W: Placed by OpenAirDocs: center of Douglas, WY, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=42.7548&lon=-105.3978&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal, 1 serious
- Status: Completed, report March 31, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41422
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA91LA097
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41422/pdf
- Page: https://openairdocs.org/ntsb/SEA91LA097

## Probable cause

AN INADVERTENT STALL WITH INADEQUATE TERRAIN CLEARANCE.  FACTORS INCLUDE FLIGHT IN MOUNTAINOUS TERRAIN AT AN ALTITUDE WHERE REMEDIAL ACTION WAS NOT POSSIBLE.

## Sequence of events

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

- Loss of control - in flight, climb
  - stall - inadvertent, pilot in command (cause)
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - mountainous/hilly (contributing factor)
  - proper altitude - not maintained, pilot in command (cause)
  - remedial action - not possible (contributing factor)

## Analysis

THE GRUMMAN AA-1B WAS OBSERVED BY ANOTHER AIRCRAFT FLYING AT LOW LEVEL WHEN IT ENTERED MOUNTAINOUS TERRAIN.  THE WITNESS OBSERVED THE AIRCRAFT AT VERY LOW ALTITUDE IN A NOSE-HIGH ATTITUDE, THEN OBSERVED IT IN WHAT HE DESCRIBED AS A STALL IMMEDIATELY BEFORE IMPACTING TREES AND TERRAIN.  THE PRIVATE PILOT IN THE LEFT SEAT OF THE GRUMMAN STATED THAT THE FLIGHT INSTRUCTOR IN THE RIGHT SEAT WAS FLYING THE AIRCRAFT AT THE TIME OF THE ACCIDENT.

## Aircraft

- Registration: [N1412R](https://openairdocs.org/deregistered/N1412R-2013-04-30), registration cancelled 2013-04-30, S/N AA1B-0512, built 1974 (OpenAirDocs)
- Reported make and model: GRUMMAN AA-1B
- Registry model: [Grumman American Avn. AA-1B](https://openairdocs.org/model/grumman-american-avn-aa-1b) (registry code 3960103) (OpenAirDocs)
- Registry engine: [Lycoming 0-235 series](https://openairdocs.org/engine/lycoming-0-235-series) (registry code 41505, 4 cycle) (OpenAirDocs)
- Category: Airplane
- Serial number: AA-1B-0512
- Engines: LYCOMING O-235-C reciprocating
- Damage: Destroyed
- Flight: Positioning, Part 91
- Operator: Paul E. Kacak
- Departed: FNL, FORT COLLINS, CO
- Destination: CPR, CASPER, WY

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 24; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; toxicology performed; flight hours: 567 total, 479 as pilot in command, 26 in the last 90 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 120° at 7 knots
- Visibility: 35 statute miles
- Lowest ceiling: 3,000 ft overcast
- Temperature: -0 °F, dew point -0 °F
- Altimeter: 29.00 inHg

## 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 19910502013999A](https://openairdocs.org/incident/19910502013999A), May 2, 1991: Gulstm AA1B, Douglas, WY, Destroyed, 1 fatal. Flew low and slow in mountain terrain nose high. Stalled. Hit trees. CFI was at controls. AA1B high stalling speed.

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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