# NTSB ANC87FA095: Piper PA-18, N159T, Sheep Mountain, AK, July 12, 1987

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Field investigation · Final report
- Date: July 11, 1987, 19:45 local (Jul 12, 1987, 03:45 UTC)
- Place: Sheep Mountain, AK
- Location: 61.8113° N, 147.5091° W: Placed by OpenAirDocs at SHEEP MOUNTAIN (SMU), within about a mile (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=61.8113&lon=-147.5091&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 2 minor
- Status: Completed, report May 2, 1988
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 4777
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC87FA095
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/4777/pdf
- Page: https://openairdocs.org/ntsb/ANC87FA095

## Sequence of events

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

- Loss of control - in flight, maneuvering
  - weather condition - low ceiling (contributing factor)
  - airspeed(vso) - not maintained, pilot in command (cause)
  - terrain condition - mountainous/hilly (contributing factor)
  - altitude - improper, pilot in command (contributing factor)
  - judgment - poor, pilot in command (cause)
  - flight into known adverse weather - continued, pilot in command (contributing factor)
  - in-flight planning/decision - improper, pilot in command (contributing factor)
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE PILOT AND HIS TWO PASSENGERS TOOK OFF IN A TWO PLACE PIPER PA-18 FROM A GLACIER AFTER DOING REPAIR WORK ON AN AIRCRAFT THAT HAD CRASHED THERE EARLIER. WEATHER CONDITIONS WERE DETERIORATING AS THEY APPROACHED THEIR DESTINATION AIRSTRIP LOCATED IN A NEARBY MOUNTAIN PASS. THE CEILING WAS ESTIMATED AT 200 FEET AGL, AND VISIBILITY AS BETWEEN 1/2 AND 3 MILES. THE PILOT SAID THAT HE FELT INTIMIDATED BY THE LOW CLOUDS AND RISING TERRAIN SURROUNDING THE AIRSTRIP AND THAT HE INADVERTENTLY STALLED THE AIRCRAFT WHILE TURNING FROM DOWNWIND TO BASE LEG.

## Aircraft

- Registration: [N159T](https://openairdocs.org/aircraft/N159T), registered now, S/N 18-2273, built 1953 (OpenAirDocs)
- Reported make and model: PIPER PA-18
- Registry model: [Piper PA-18-105 SPECIAL](https://openairdocs.org/model/piper-pa-18-105-special) (registry code 7101808) (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: 18-2273
- Engines: LYCOMING O-320 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Business, Part 91
- Registered owner: Cumin L. Wiles
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, July 15, 1986, 50 hours before
- Departed: MATANUSKA GAL, AK
- Destination: SMU, SHEEP MT. LODGE, AK
- Airport: SMU, Sheep Mountain, runway 22, 2,200 × 50 ft, gravel

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 33; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, expired; seat: front; flight hours: 872 total, 38 in this make and model, 795 as pilot in command, 45 in the last 90 days, 6 in the last 24 hours

## Weather

- Conditions: Day
- Wind: 240° at 7 knots
- Lowest ceiling: 200 ft overcast
- Temperature: 57 °F, dew point -0 °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 19870711038779A](https://openairdocs.org/incident/19870711038779A), Jul 11, 1987: Piper PA18105SPEC, Sheep Mountain, AK, Substantial damage. The aircraft stalled on final, recovered and hit a hill. The pilot was carrying a passenger in the baggage area.

## Other investigations on N159T (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 ANC90LA131](https://openairdocs.org/ntsb/ANC90LA131), Aug 3, 1990: Piper PA-18 (N159T), Falls Creek, AK, substantial damage. Probable cause: PILOT-IN-COMMAND'S FAILURE TO MAINTAIN AIRCRAFT CONTROL.

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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