NTSB Factual Report

On September 10, 2004, at 1150 eastern daylight time, N172WW, a Cessna 172M, was substantially damaged during an aborted takeoff at the Medina Municipal Airport (1G5), Medina, Ohio. The certificated private pilot was not injured. Visual meteorological conditions prevailed for the local personal flight conducted under 14 CFR Part 91.

According to the pilot, the purpose of the flight was to perform three takeoffs and landings to maintain his 90-day currency to carry passengers. He completed three takeoffs and landings from runway 01 without incident, and then decided to perform one more. During the fourth takeoff, as the pilot rotated at 60 knots, he felt the airplane was "slow to lift." The pilot decided the airplane would not make it over the roadway and wires at the end of the runway, and he aborted the takeoff. He reduced the power to idle, applied the brakes, and used 40 degrees of flaps; however, the airplane traveled off the end of the runway, impacted a fence, and nosed over in a ditch.

A witness, who was on the taxiway located at the departure end of runway 01, heard a change of engine power during the airplane's takeoff roll, followed by the sound of tires "squelling on the pavement." He then observed the airplane travel off the end of runway 01 and impact a fence.

Examination of the Lycoming engine by a Federal Aviation Administration (FAA) inspector, after the accident, revealed low compression (34/80) in the number 3 cylinder. The cylinder was then removed from the engine and further examination revealed that a cylinder ring was fractured.

According to the engine logbook, the last 100-hour inspection was performed on August 20, 2004. The entry for the inspection revealed a compression check of the number 3 cylinder resulted in a reading of 55/80 psi. The number 1, 2, and 4 compression check values were 66/80, 70/80, and 62/80, respectively.

The airplane had flown approximately 1 hour since the annual inspection.

According to 14 CFR Part 43 Appendix D, Scope and Detail of Items to be Included in Annual and 100-hour Inspections, "Each person shall inspect components of the engine and nacelle as follows...Internal engine - for cylinder compression...If there is a weak cylinder compression, [inspect] for improper internal condition and improper internal tolerances."

Lycoming Service Instruction No. 1191A, Cylinder Compression, stated in part, "Pressure readings for all cylinders should be nearly equal...a difference of 10 to 15 psi indicates an investigation should be made...if the pressure reading for cylinders is below 60 psi...removal and overhaul of the cylinders should be considered."

NTSB Probable Cause

The partial loss of engine power due to inadequate maintenance and by failure to comply with service instruction for low engine compression.