NTSB Factual Report

On July 18, 2001, at 1105 central daylight time, a Cessna 172C, N1860Y, sustained substantial damage during a forced landing to a cornfield. The student pilot was not injured. The 14 CFR Part 91 solo instructional flight had departed Lincoln Municipal Airport (LNK), Lincoln, Nebraska, at 1010 on a solo cross country flight en route to Grand Island (GRI), Nebraska. The student pilot had started the descent from 6,500 feet msl about 10 nautical miles from GRI when there was a complete loss of engine power. The student pilot declared a MAYDAY and executed a forced landing to a cornfield. The left and right wing spars were substantially damaged during landing roll. Visual meteorological conditions prevailed and a VFR flight plan had been filed.

The student pilot reported the en route altitude was 6,500 feet msl. He contacted GRI at approximately 1100. He received a clearance to land on runway 17 and advised to contact the tower when he was 1 mile from the airport. He reported, "Soon thereafter the engine sputtered and stopped." He advised the tower of the engine failure and was cleared to land on runway 22 at "pilot's discretion."

The student pilot attempted an engine air start but was unsuccessful. He reported he was unable to land at the airport. At 400 feet agl, he saw power lines running north and south so he turned north to avoid the power lines and landed cross row in a cornfield. During the landing roll, the airplane started to nose over and then "cart wheeled" and came to rest on its main landing gear.

The Federal Aviation Administration Airworthiness inspector examined the airplane. He reported there were no preexisting anomalies to the airframe or engine. The engine was test run and it started without hesitation.

The 1056 observed weather at GRI was: wind 130 degrees at 6 knots, sky clear, visibility 10 miles, temperature 29 degrees C, dew point 20 degrees C, altimeter 29.87.

According to the Transport Canada "Carburetor Icing Graph", the existing weather conditions at GRI fell in the region of "Serious icing - descent power."

The FAA issued Advisory Circular (AC) 20-113, "Pilot Precautions and Procedures To Be Taken In Preventing Aircraft Reciprocating Engine Induction System and Fuel System Icing Problems." The AC stated, "…the pilot should regularly use heat under conditions known to be conducive to atmospheric icing…" in order to prevent accidents due to induction system icing. One of the procedures to reduce the likelihood of induction system icing stated, "Heat should be applied for a short time to warm the induction system before beginning a prolonged descent with the engine throttled and left on during the descent. Power lever advancement should be performed periodically during descent to assure that power recovery can be achieved. The pilot should be prepared to turn heat off after power is regained to resume level flight or initiate a go-around from an abandoned approach."

The student pilot had a total of 41 hours of flight time.

NTSB Probable Cause

The procedures for using carburetor heat not followed by the student pilot and the unsuitable terrain encountered during the forced landing. Additional factors included the carburetor icing conditions, the carburetor icing, the student pilot's lack of experience, and the crop.