# NTSB ANC89LA036: Piper PA-18, N4280Z, Girdwood, AK, January 21, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: January 21, 1989, 16:00 local (20:00 UTC)
- Place: Girdwood, AK
- Coordinates: 60.900436, -148.909088 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=60.9004&lon=-148.9091&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report September 28, 1990
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5161
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC89LA036
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5161/pdf
- Page: https://openairdocs.org/ntsb/ANC89LA036

## Probable cause

THE PILOT'S FAILURE TO MAINTAIN CONTROL OF THE AIRPLANE WHILE ATTEMPTING TO TAKEOFF FROM A SLOPED TERRAIN THAT WAS TOO STEEP FOR A SAFE OPERATION. CONTRIBUTING TO THE ACCIDENT WAS THE DOWNHILL, ICY TERRAIN CONDITIONS AND THE PILOT'S OVERCONFIDENCE IN BOTH HIS AND THE AIRPLANE'S ABILITY..

## Sequence of events

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

- Loss of control - on ground/water, taxi - to takeoff
  - terrain condition - downhill (contributing factor)
  - terrain condition - icy (contributing factor)
  - unsuitable terrain or takeoff/landing/taxi area - selected, pilot in command (cause)
  - overconfidence in personal ability, pilot in command (contributing factor)
  - overconfidence in aircraft's ability, pilot in command (contributing factor)
- Gear collapsed, taxi - to takeoff
- Dragged wing,rotor,pod,float or tail/skid, taxi - to takeoff

## Analysis

THE AIRLINE TRANSPORT PILOT LANDED UP-SLOPE ON A GLACIER AND WAS TURNING TO TAKEOFF DOWN-SLOPE WHEN TAILWIND AND 10-20 DEGREE SLOPE CAUSED THE AIRCRAFT TO TURN THROUGH THE DESIRED TAKEOFF HEADING, AND TO SLIDE SIDEWAYS. THE RIGHT SKI DUG INTO THE SNOW, CAUSING THE RIGHT MAIN LANDING GEAR TO COLLAPSE, AND THE RIGHT WING TO CONTACT THE FROZEN SURFACE. THE CRASH SITE ELEVATION WAS ABOUT 4,400 FEET MSL.

## Aircraft

- Registration: [N4280Z](https://openairdocs.org/aircraft/N4280Z), registered now, S/N 18-8528, built 1967 (OpenAirDocs)
- Reported make and model: PIPER PA-18
- Registry model: [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150) (registry code 7101828) (OpenAirDocs)
- Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 188528
- Airframe hours: 5174
- Engines: LYCOMING O-320 150 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Gerald G. Chisum
- Registered owner: Mejo Dkon Ruckman
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, May 14, 1988, 20 hours before
- Departed: GIRDWOOD, AK
- Destination: AK

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; airline transport; airplane ratings: multi-engine sea, single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: front; flight hours: 21,000 total, 300 in this make and model, 20,000 as pilot in command, 30 in the last 90 days, 20 in the last 30 days, 3 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 30° at 6 knots
- Visibility: 60 statute miles
- Lowest ceiling: none
- Temperature: 16 °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 19890121001029A](https://openairdocs.org/incident/19890121001029A), Jan 21, 1989: Piper PA18150, Girdwood, AK, Substantial damage. Landed upslope on a glacier, turning to takeoff downslope began sliding right ski dug in collapsing the gear.

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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