CEN11LA177

NTSB accident investigation · Piper PA-16 · Lake Koshkonong, WI · February 5, 2011

Accident · Minor injuriesLimited investigationFinal report
Date
February 5, 2011, 15:00 local (21:00 UTC)
Place
Lake Koshkonong, WI
Injuries
1 minor, 1 uninjured
Damage
Substantial damage
Phase of flight
Maneuvering
Aircraft
N5945HPiper PA-16
Defining event
Maneuvering-low-alt flying: Low altitude operation/event
Weather
Visual (VMC) · Day
Status
Completed · report December 19, 2011
Report
Approved by Office Director
NTSB office
Central Region
Parties
Federal Aviation Administration - Milwaukee FSDO
FAA report
20110205001819A
Case key
78306

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

Probable cause

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

Findings · 2

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Engine (reciprocating)Aircraft › Aircraft power plant · Not specifiedPiper PA-16: 2 casesAll aircraft: 497 casesProbable cause
Terrain: snowy/icy terrainEnvironmental issues › Physical environment · Contributed to outcomePiper PA-16: 1 caseAll aircraft: 77 cases

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

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
Reported as
Piper PA-16
Category
Airplane
Serial number
16-568
Airframe hours
1,704
Engine
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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
56
Injuries
None
Certificate
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

Docket · 6

The files NTSB released with the investigation on November 2, 2011, on NTSB’s docket system: statements, records, photos and specialists’ reports. 1.8 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.