Aviation Accident Summaries

Aviation Accident Summary ERA09LA372

Shepherdsville, KY, USA

Aircraft #1

N172TJ

CESSNA 172D

Analysis

The pilot was in cruise flight between 1,700 and 2,200 feet mean sea level when the engine rpms decreased. He applied throttle with negative results. The airplane continued to descend and he performed a forced landing to a soybean field. Review of the airplane logbooks revealed that the airplane had flown 2.29 hours since the last annual inspection. Postaccident examination of the airframe and flight controls revealed no anomalies; however, the mixture control cable was found to be separated from the mixture control arm. The mixture cable wire tip was not bent 90 degrees to prevent it from being withdrawn if the attaching nut should become loose, as required by the maintenance manual. The cable did not exhibit any signs of damage or stretching, and it was not broken at the attach point to the attaching bolt in the mixture control arm of the carburetor. The mechanic who performed the last annual inspection stated that he did not remember if he did or did not bend the cable 90 degrees.

Factual Information

On June 27, 2009, at 1010 eastern daylight time, a Cessna 172D, N172TJ, registered to and operated by a private owner, as a Title 14 Code of Federal Regulations Part 91 personal flight, lost engine power while in cruise flight in the vicinity of Shepherdsville, Kentucky. Visual meteorological conditions prevailed and no flight plan was filed. The airplane received substantial damage and the private pilot reported no injuries. The flight originated at Lick Airport, Louisville, Kentucky, at 0945. The pilot stated the engine was set at 2,400 rpm and the airplane was between 1,700 feet to 2,200 feet mean sea level, when the engine rpm decreased. He applied throttle with negative results. The airplane continued to descend and he performed a forced landing to a soybean field. The nose landing gear separated on landing roll out, the nose pitched down, and both wings received structural damage. Examination of the airplane by a Federal Aviation Administration (FAA) inspector revealed the forward cabin area was not damaged. The throttle was in the full forward position and the carburetor heat was in the off position. The fuel selector valve was in the “Off” position. Continuity of the flight controls was confirmed from the flight controls aft to all flight control surfaces. The right main landing gear remained attached to the airframe and the wheel pant cover was damaged. The left main landing gear remained attached to the airframe and was not damaged. The left and right main fuel tanks were observed and visually found to contain considerable amount of fuel. The fuel caps had a tight seal and the fuel vent line was clear of obstructions. The left wing fuel sump was checked and approximately 3.25 ounces of water was removed. The right wing fuel sump was checked and approximately 2 ounces of water was removed. A fuselage low point drain under the aircraft was not installed. The fuel inlet supply line was removed and fuel was present to the carburetor and no evidence of water was noted. The inlet screen was removed from the carburetor and was observed to have a small amount of a white sludgy substance on the screen, but it did not obstruct the screen. The empennage exhibited minor skin wrinkling behind the main landing gear attachment points. The horizontal stabilizers, vertical fin and rudder were not damaged. Examination of the engine revealed the carburetor had separated from its mounting pad. The fuel inlet supply line was attached and not damaged. The carburetor heat cable was attached and operated. The throttle cable and throttle arm of the carburetor remained attached to the engine case and the throttle operated freely. The mixture control cable was separated from the mixture control arm, the cable did not exhibit any signs of damage or stretching, and it was not broken at the attach point to the attaching bolt in the mixture control arm of the carburetor. The mixture cable wire tip was not bent 90 degrees to prevent it from being withdrawn if the attaching nut should become loose. The FAA inspector noted, "The mixture control cable attaching bolt to the mixture control arm was not damaged. The mixture control cable attaching bolt was observed to have what appears to be a newly installed self locking steel nut instead of a castellated nut. The steel locking nut appears to have been relatively recently installed. The mixture control cable was able to be pushed into the hole in the mixture control cable attaching bolt with very little restriction." The crankshaft was rotated by hand. Valve and drive train continuity were confirmed, and continuity was established with all accessory gears. Suction and compression were obtained. Test for spark was conducted and spark was observed. Both impulse couplings of the magnetos were heard to be functional. Examination of the aircraft logbooks revealed the last annual inspection was conducted on October 3, 2008. The tachometer reading at the time of the annual inspection was 1636.9 hours. The tachometer reading at the accident site was 1638.68 hours. The airplane had flown 2.29 hours since the annual inspection. The Cessna Aircraft Company Service Manual 100 Series, Section 12, Powerplant, page 12-23, paragraph 12-62, MIXTURE CONTROL RIGGING, f. states, "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, "he did not remember if he did that or not."

Probable Cause and Findings

The mechanic's improper inspection of the mixture control cable.

 

Source: NTSB Aviation Accident Database

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