Accident Overview
On June 27, 2009, at 1010 eastern daylight time, a Cessna 172D, registration N172TJ, operated by a private owner as a Title 14 Code of Federal Regulations Part 91 personal flight, experienced a loss of engine power while in cruise flight near Shepherdsville, Kentucky. Visual meteorological conditions prevailed, and no flight plan was filed. The airplane sustained substantial damage, and the private pilot reported no injuries. The flight had originated from Lick Airport in Louisville, Kentucky, at 0945.
Pilot Actions
The pilot reported that the engine was set at 2,400 rpm with the airplane between 1,700 and 2,200 feet mean sea level when the engine rpm decreased. Application of throttle yielded no response. As the airplane continued to descend, the pilot executed a forced landing to a soybean field. During the landing roll, the nose landing gear separated, causing the nose to pitch down and resulting in structural damage to both wings.
Aircraft Examination
A Federal Aviation Administration (FAA) inspector examined the airplane. The forward cabin area was not damaged. The throttle was found in the full forward position, and the carburetor heat was off. The fuel selector valve was in the “Off” position. Continuity of the flight controls was confirmed from the cockpit aft to all control surfaces. The right main landing gear remained attached to the airframe, though its wheel pant cover was damaged; the left main landing gear was attached and undamaged.
Fuel examination revealed that both left and right main tanks contained considerable fuel. The fuel caps had a tight seal, and the fuel vent line was clear. The left wing fuel sump yielded approximately 3.25 ounces of water, while the right wing sump yielded about 2 ounces. A fuselage low-point drain under the aircraft was not installed. The fuel inlet supply line was removed and found to contain fuel to the carburetor with no evidence of water. The carburetor inlet screen showed a small amount of a white sludgy substance but was not obstructed.
The empennage exhibited minor skin wrinkling behind the main landing gear attachment points. The horizontal stabilizers, vertical fin, and rudder were undamaged.
Engine Examination
Examination of the engine revealed that the carburetor had separated from its mounting pad. The fuel inlet supply line was attached and undamaged. The carburetor heat cable was attached and functional. The throttle cable and throttle arm remained attached to the engine case, and the throttle operated freely. The mixture control cable was separated from the mixture control arm; the cable showed no signs of damage or stretching, and it was not broken at the attach point. The mixture cable wire tip was not bent 90 degrees as specified in the manufacturer's manual to prevent withdrawal if the attaching nut loosened. The FAA inspector noted that the mixture control cable attaching bolt appeared to have a newly installed self-locking steel nut instead of a castellated nut, and the cable could be pushed into the bolt hole with very little restriction.
The crankshaft was rotated by hand, confirming valve and drive-train continuity as well as continuity with all accessory gears. Suction and compression were obtained, and a spark test showed positive results. Both impulse couplings of the magnetos were heard to be functional.
Maintenance History
Examination of the aircraft logbooks indicated that the last annual inspection was conducted on October 3, 2008, at a tachometer reading of 1636.9 hours. The tachometer reading at the accident site was 1638.68 hours, meaning the airplane had flown 2.29 hours since the annual inspection. The Cessna Aircraft Company Service Manual for the 100 Series, Section 12, Powerplant, page 12-23, paragraph 12-62, Mixture Control Rigging, specifies to “Bend the wire tip 90 degrees to prevent it from being withdrawn if the attaching nut should become loose.” The mechanic who performed the annual inspection stated that he did not remember if he performed that step.