# NTSB WPR11CA040: Piper PA-18-150, N4389Z, Carnation, WA, November 3, 2010

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Data collection · Final report
- Date: November 3, 2010, 16:30 local (23:30 UTC)
- Place: Carnation, WA
- Coordinates: 47.670555, -121.925552 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.6706&lon=-121.9256&mi=10
- Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping)
- Defining event: [Approach-VFR pattern final: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report March 16, 2011
- Report: Approved by Office Director
- NTSB office: Western Pacific Region
- Parties: Seattle FSDO
- NTSB case key (mKey): 77753
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11CA040
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/77753/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=77753
- Page: https://openairdocs.org/ntsb/WPR11CA040

## Probable cause

The pilot's failure to attain the proper touchdown point during a practice off-airport landing.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Action: incorrect action performance](https://openairdocs.org/ntsb-findings/02041015): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Piper PA-18-150, 12 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md?model=7101828), [All aircraft, 1,386 cases](https://openairdocs.org/ntsb-findings/02041015/cases.md)
- [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Contributed to outcome; cases with it: [Piper PA-18-150, 6 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=7101828), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md)
- [Performance/control parameters: descent/approach/glide path](https://openairdocs.org/ntsb-findings/01062040): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Piper PA-18-150, 8 cases](https://openairdocs.org/ntsb-findings/01062040/cases.md?model=7101828), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/01062040/cases.md)
- [Wind: downdraft](https://openairdocs.org/ntsb-findings/03034035): Environmental issues › Conditions/weather/phenomena · Response/compensation (probable cause); cases with it: [Piper PA-18-150, 6 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md?model=7101828), [All aircraft, 178 cases](https://openairdocs.org/ntsb-findings/03034035/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Approach-VFR pattern final: Loss of lift](https://openairdocs.org/ntsb-events/500); cases with it: [Piper PA-18-150, 2 cases](https://openairdocs.org/ntsb-events/500/sequence.md?model=7101828), [All aircraft, 252 cases](https://openairdocs.org/ntsb-events/500/sequence.md)
- [Approach-VFR pattern final: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470) (defining event); cases with it: [Piper PA-18-150, 115 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7101828), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)

## Analysis

During a local area personal flight, the pilot decided to make a practice landing on a gravel bar near the middle of a river. With limited landing distance, the pilot decided to fly his approach at a low airspeed, with the intention of touching down at the very edge of the bar. While on short final, the airplane encountered a downdraft and its main landing gear tires touched the surface of the water, whereupon it flipped over onto its back and came to rest upon the surface of the gravel bar. According to the pilot, there were no mechanical malfunctions with the airplane. As a result of the accident sequence, the top of the rudder and one lift strut were bent.

## Factual narrative

During a local area personal flight, the pilot, who was flying a tail wheel-equipped airplane, decided to make a "practice Landing" on a gravel bar near the middle of a river. Because of the limited landing distance, the pilot flew his approach at a low airspeed, with the intention of touching down at the very edge of the bar. While on short final, the airplane encountered a downdraft and its main landing gear tires touched the surface of the water whereupon it flipped over onto its back and came to rest upon the surface of the gravel bar. According to the pilot, there were no anomalies associated with the airplane's flight control systems. As a result of the accident sequence, the top of the rudder and one lift strut were bent.

## Aircraft

- Registration: [N4389Z](https://openairdocs.org/aircraft/N4389Z), registered now, S/N 18-8716, built 1968 (OpenAirDocs)
- Reported make and model: PIPER PA-18-150
- 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: 18-8716
- Airframe hours: 1201
- Engines: LYCOMING O-320 SERIES 180 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: James D. Unger
- Registered owner: Copper Mountain Aviation LLC
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, December 24, 2009
- Departed: W16, Monroe, WA
- Destination: W16, Monroe, WA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 58; injuries: none; private; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 3; last flight review August 1, 2009; seat: front; flight hours: 3,120 total, 350 in this make and model, 50 in the last 90 days, 20 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 70 °F

## Docket (1 files)

The files NTSB released with the investigation on November 22, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=77753. 747 KB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 747 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40339794&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF

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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