# NTSB CEN11LA177: Piper PA-16, N5945H, Lake Koshkonong, WI, February 5, 2011

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: February 5, 2011, 15:00 local (21:00 UTC)
- Place: Lake Koshkonong, WI
- Coordinates: 42.888053, -88.957221 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.8881&lon=-88.9572&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220)
- Highest injury: Minor injuries
- Injuries: 1 minor, 1 uninjured
- Status: Completed, report December 19, 2011
- Report: Approved by Office Director
- NTSB office: Central Region
- Parties: Federal Aviation Administration - Milwaukee FSDO
- NTSB case key (mKey): 78306
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11LA177
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/78306/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=78306
- Page: https://openairdocs.org/ntsb/CEN11LA177

## Probable cause

A loss of engine power for undetermined reasons during a low-altitude pass over a frozen lake.

## Findings

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

- [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Not specified (probable cause); cases with it: [Piper PA-16, 2 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=7101602), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md)
- [Terrain: snowy/icy terrain](https://openairdocs.org/ntsb-findings/03021030): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Piper PA-16, 1 case](https://openairdocs.org/ntsb-findings/03021030/cases.md?model=7101602), [All aircraft, 77 cases](https://openairdocs.org/ntsb-findings/03021030/cases.md)

## Sequence of events

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

- [Maneuvering-low-alt flying: Powerplant sys/comp malf/fail](https://openairdocs.org/ntsb-events/340); cases with it: [Piper PA-16, 1 case](https://openairdocs.org/ntsb-events/340/sequence.md?model=7101602), [All aircraft, 820 cases](https://openairdocs.org/ntsb-events/340/sequence.md)
- [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Piper PA-16, 1 case](https://openairdocs.org/ntsb-events/220/sequence.md?model=7101602), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md)
- [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Piper PA-16, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=7101602), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing-flare/touchdown: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Piper PA-16, 9 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7101602), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)
- [Landing-flare/touchdown: Nose over/nose down](https://openairdocs.org/ntsb-events/096); cases with it: [Piper PA-16, 6 cases](https://openairdocs.org/ntsb-events/096/sequence.md?model=7101602), [All aircraft, 2,287 cases](https://openairdocs.org/ntsb-events/096/sequence.md)

## Analysis

During a local flight, the pilot decided to overfly a frozen lake at low altitude. He reduced engine power to idle and the airplane descended to about 10 feet above the lake. The pilot attempted to arrest the descent with an increase of engine power; however, advancing the engine throttle did not result in an increase in engine power. A forced landing was immediately performed on the frozen lake. The airplane encountered an area of deep snow during touchdown and subsequently nosed over, damaging the vertical stabilizer, rudder, right wing, fuselage, and engine firewall. A postaccident examination of the engine did not reveal any preimpact anomalies or failures that would have prevented its normal operation. A postaccident engine run was not performed due to the observed airframe and propeller damage. Although the pilot reported that he did not apply carburetor heat during the airplane's descent to the lake, a review of a carburetor icing probability chart and the weather at the time of the accident revealed that the conditions were not conducive to the accretion of carburetor ice. Local law enforcement reported that upon their arrival at the accident site there was ample fuel found within the airplane's fuel tanks.

## Factual narrative

On February 5, 2011, at 1500 central standard time, a Piper model PA-16 airplane, N5945H, was substantially damaged when it nosed-over during a forced landing on Lake Koshkonong, Wisconsin. The pilot was not injured. The passenger sustained minor injuries. The airplane was registered to and operated by a private pilot under the provisions of 14 Code of Federal Regulations Part 91. Day visual meteorological conditions prevailed for the flight, which was operated without a flight plan. The flight departed Palmyra Municipal Airport (88C), Palmyra, Wisconsin, at approximately 1330 for the local flight. According to the pilot, during the local flight he decided to overfly Lake Koshkonong at a low altitude. He reduced engine power to idle and the airplane descended from 1,200 feet mean sea level to about 10 feet above the lake. The pilot attempted to arrest the airplane's descent with an increase of engine power; however, advancing the engine throttle did not result in an increase in engine power. A forced landing was immediately performed on the frozen lake. The pilot reported that he was not concerned about landing on the frozen lake because he believed there was bare ice beneath the airplane; however, during touchdown the airplane encountered an area of deep snow and subsequently nosed-over. The pilot and passenger were able to exit the airplane through the cabin doors. The airplane sustained substantial damage to the vertical stabilizer, rudder, right wing, fuselage structure, and the engine firewall. The pilot reported that at departure the airplane had 28 gallons of automobile gas on board and following the accident he had repositioned the airplane's fuel valve to the OFF position. Local law enforcement reported that upon reaching the accident site there was the smell of fuel and the airplane's fuel tanks contained ample fuel. In a postaccident interview, the pilot confirmed that he had not applied carburetor heat during the descent at idle power to the lake. He noted that after identifying the engine was unresponsive to throttle inputs, he did not have enough time to apply carburetor heat before the airplane touched down on the frozen lake. A review of a carburetor-icing probability chart and weather conditions at the time of the accident did not support the accretion of carburetor ice. Further examination of the engine did not reveal any preimpact anomalies or failures that would have prevented normal operation. A postaccident engine run was not performed due to observed airframe and propeller damage.

## Aircraft

- Registration: [N5945H](https://openairdocs.org/aircraft/N5945H), registered now, S/N 16-568, built 1949 (OpenAirDocs)
- Reported make and model: PIPER PA-16
- Registry model: [Piper PA-16](https://openairdocs.org/model/piper-pa-16) (registry code 7101602) (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: 16-568
- Airframe hours: 1704
- Engines: Lycoming O-235-C1 108 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, November 4, 2010
- Departed: 88C, Palmyra, WI
- Destination: 88C, Palmyra, WI

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 56; injuries: none; private; airplane ratings: single-engine land; seat: left; flight hours: 227 total, 123 as pilot in command, 9 in the last 90 days, 2 in the last 30 days, 0 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 260° at 5 knots
- Visibility: 10 statute miles
- Lowest ceiling: 8,000 ft broken
- Temperature: 28 °F, dew point 14 °F
- Altimeter: 29.59 inHg
- Observed at: KJVL, 14 nm away

## 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 20110205001819A](https://openairdocs.org/incident/20110205001819A), Feb 5, 2011: Piper PA-16, Fort Atkinson, WI, Substantial damage. On February 5, 2011 at 1505 CT, the pilot of a Piper PA-16 made an emergency landing on lake koshkonong, near Fort Atkinson, WI. The pleasure flight was…

## Docket (6 files)

The files NTSB released with the investigation on November 2, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=78306. 1.8 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 927 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356957&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Local Law Enforcement Incident Report (item 2, .PDF, 586 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356959&FileExtension=.PDF&FileName=Local%20Law%20Enforcement%20Incident%20Report-Redacted.PDF
- Memorandum of Conversation (FAA Inspector McCullion) (item 3, .PDF, 77 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356961&FileExtension=.PDF&FileName=Memorandum%20of%20Conversation%20(FAA%20Inspector%20McCullion)-Master.PDF
- FAA Inspector Statement (item 4, .PDF, 74 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356962&FileExtension=.PDF&FileName=FAA%20Inspector%20Statement-Redacted.PDF
- Local Weather Reports (item 5, .PDF, 38 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356963&FileExtension=.PDF&FileName=Local%20Weather%20Reports-Master.PDF
- FAA Special Airworthiness Information Bulletin (Carburetor Icing Prevention) (item 6, .PDF, 105 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40356964&FileExtension=.PDF&FileName=FAA%20Special%20Airworthiness%20Information%20Bulletin%20(Carburetor%20Icing%20Prevention)-Master.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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