Thomasville, GA, USA
N73PC
CHAMPION 7ECA
The pilot stated that as the airplane touched down on the runway he heard a "pop" or a "snap" sound. The airplane collided with the runway on its right side and slid down the surface until coming to rest. A postaccident examination of the airplane revealed that a bolt on the right main landing gear was absent. The bolt, which holds the oleo, or shock absorber, unit in the housing, was incorrectly installed above and through the oleo assembly. This resulted in the bolt coming out of the housing, which in turn led to the cylinder and spring overextending out of its respective housing. There was no evidence of fatigue, stress, or corrosion on the failed component. A review of the airframe logbook indicated that the last annual inspection was conducted about 45 days and 3.8 flight hours prior to the accident. The airplane's parts manual stated that after performing maintenance of the oleo the mechanics should be certain that the bolt passes through the retainer at the top end of the oleo. The manual further warned that if this is not done, the oleo will fall out when the airplane takes off.
On June 17, 2010, at 1135 eastern daylight time, a Champion 7ECA, N73PC, registered to N117VR LLC and operated as a 14 Code of Federal Regulations Part 91 personal flight, experience a right main landing gear oleo strut separation during a wheel landing at Thomasville Regional Airport (TVI), Thomasville, Georgia. Visual meteorological conditions prevailed and no flight plan was filed. The airplane received substantial damage. The commercial pilot reported no injuries. The flight originated from Merritt Island Airport, Merritt Island, Florida at 0820. The pilot stated upon arrival at TVI he made a radio call on the common traffic advisory frequency and announced his entry into the traffic pattern to runway 04. He completed all before landing checks, slowed the airplane down to 65 mph on final approach, and made a wheel landing. As soon as the main landing gear touched down on the runway, he heard a "pop" or a "snap" sound. The airplane then collided with the runway on its right side and slid down the runway until it came to a stop. Examination of the airplane revealed that it received structural damage to the right main landing gear attachment point on the fuselage. According to the Federal Aviation Administration inspector and airframe and power plant mechanic that inspected the landing gear, the bolt that held the oleo unit in the housing was installed above and through the oleo assembly, which eventually allowed the bolt to fall out of the housing. The oleo (PN 3-665) on the right side failed internally, allowing the cylinder and spring to over extend out of its housing. There was no evidence of fatigue, stress, or corrosion on the failed component. Review of the airframe logbook revealed the last annual inspection was conducted on May 4, 2010, at a tachometer time of 1,353.66 hours. The airplane had flown 3.8 hours since the last annual inspection. The airframe and power plant mechanic who performed the last inspection stated he did not perform any maintenance on the right main landing gear. The previous annual inspection was conducted by a different mechanic on December 10, 2007- at a tachometer time of 1,289 hours. That mechanic indicated in the sign-off that the seals were replaced in the oleo main gear. The airplane had accumulated 69 hours since that inspection. Attempts to locate that mechanic were unsuccessful. No work was performed on the landing gear during the annual inspection conducted on August 12, 2006. Review of the Citabria Maintenance Manual and Parts Manual for the landing gear group states for the OLEO PISTON ASSEMBLY, "This assembly consists of spring, plunger, and hydraulic oil retaining cylinder....If it is necessary to change the graphite packing, release oleo unit from the oleo case assembly by removing the bolt at the top of the oleo case. Drive bushing out of spring retaining washer and remove retainer and oleo spring. Pry the plug at the top of the cylinder loose and remove old packing. Press the new into place around the piston rod and replace parts. Extreme care should be taken in replacing the oleo in the old case. Be certain that the bolt passes through the retainer at the top end of the oleo. If this is not done, the oleo will fall out when the aircraft takes off."
The improper reinstallation of the airplane’s oleo piston assembly during an annual inspection, resulting in the collapse of the right main landing gear during touchdown.
Source: NTSB Aviation Accident Database
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