# NTSB ANC90LA113: Cessna 180B, N3125W, Butterfly Lake, AK, July 3, 1990

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: July 2, 1990, 19:00 local (Jul 3, 1990, 03:00 UTC)
- Place: Butterfly Lake, AK
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report February 8, 1993
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5401
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC90LA113
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5401/pdf
- Page: https://openairdocs.org/ntsb/ANC90LA113

## Probable cause

THE PILOT FAILED TO RETRACT THE AIRPLANE'S WHEEL PRIOR TO A WATER LANDING. CONTRIBUTING FACTORS ARE HIS FAILURE TO FOLLOW ESTABLISHED PROCEDURES/DIRECTIVES, AND HABIT INTERFERENCE CAUSED BY HIS CONCERN OVER AN AIR TRAFFIC CONFLICT DURING THE PRECEDING TAKEOFF.

## Sequence of events

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

- Nose over, landing - roll
  - wheels down landing in water - inadvertent, pilot in command (cause)
  - procedures/directives - not followed, pilot in command (contributing factor)
  - habit interference, pilot in command (contributing factor)

## Analysis

THE PILOT REPORTED THAT HE FORGOT TO RETRACT THE WHEEL PORTION OF HIS AMPHIBIOUS FLOAT EQUIPPED AIRPLANE FOLLOWING A TAKEOFF FROM A HARD SURFACED RUNWAY. SHORTLY THEREAFTER, HE LANDED IN THE WATER WITH THE WHEELS EXTENDED AND IMMEDIATELY NOSED OVER. THE PILOT SAID THAT HE FELT RUSHED DURING HIS PRECEDING TAKEOFF DUE TO A POTENTIAL AIR TRAFFIC CONFLICT, AND HE SUSPECTS THAT HIS CONCERN FOR THE LOCATION OF THE APPROACHING TRAFFIC INTERRUPTED HIS NORMAL HABIT OF RETRACTING THE GEAR.

## Aircraft

- Registration: [N3125W](https://openairdocs.org/aircraft/N3125W), registered now, S/N 50584, built 1959 (OpenAirDocs)
- Reported make and model: CESSNA 180B
- Registry model: [Cessna 180B](https://openairdocs.org/model/cessna-180b) (registry code 2072606) (OpenAirDocs)
- Registry engine: [Continental O-470 series](https://openairdocs.org/engine/continental-o-470-series) (registry code 17026, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 50584
- Engines: CONTINENTAL O-470K 230 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: Raymond L. Thomas
- Departed: ANC, ANCHORAGE, AK
- Airport: NONE, Butterfly Lake

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; private; airplane ratings: single-engine sea; medical: class 2, valid medical--w/ waivers/lim; flight hours: 900 total, 420 in this make and model, 840 as pilot in command

## Weather

- Conditions: Visual (VMC), Day
- Wind: 155° at 8 knots
- Visibility: 60 statute miles
- Lowest ceiling: none
- Temperature: 75 °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 19900702026679A](https://openairdocs.org/incident/19900702026679A), Jul 2, 1990: Cessna 180B, Butterfly Lake, AK, Substantial damage. Forgot to retract wheels on amphibious floats for landing in water. Aircraft flipped over.

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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