Accident Overview
On February 5, 2011, at 1500 central standard time, a Piper PA-16 airplane, registered as N5945H, was substantially damaged when it nosed over during a forced landing on Lake Koshkonong, Wisconsin. The pilot was not injured, and the passenger sustained minor injuries. The airplane was operated by a private pilot under 14 Code of Federal Regulations Part 91. Day visual meteorological conditions prevailed, and the flight was conducted without a flight plan. The airplane departed Palmyra Municipal Airport (88C), Palmyra, Wisconsin, at approximately 1330 for a local flight.
Pilot's Account
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 descent by increasing engine power, but advancing the throttle did not result in an increase in 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 deep snow and subsequently nosed over. The pilot and passenger exited through the cabin doors.
Damage and Fuel Details
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 onboard. Following the accident, the pilot repositioned the fuel valve to the OFF position. Local law enforcement reported that upon reaching the accident site, there was a smell of fuel and the airplane's fuel tanks contained ample fuel.
Engine and Carburetor Ice Investigation
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 that the engine was unresponsive to throttle inputs, he did not have enough time to apply carburetor heat before touchdown. A review of a carburetor-icing probability chart and the 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.