On January 21, 2011, at 1357 Pacific standard time, a Piper PA-28R-201T, N47589, sustained substantial damage when the left main landing gear collapsed during landing roll at John Wayne Airport, Santa Ana, California. The private pilot and his passenger were not injured. The pilot/owner was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the personal cross-country flight, which had originated from Mesquite, Nevada, about 1150. A flight plan had not been filed. The pilot said that when he put the landing gear down, the nose wheel indicated unsafe. He recycled the landing gear and it still indicated unsafe. He flew by the air traffic control tower and the controller reported that it looked like the landing gear was down. However, on landing roll, the left main landing gear collapsed. The left aileron sustained substantial damage. A Piper manufacturer’s representative and two Federal Aviation Administration inspectors examined the airplane on February 1, 2011. They found that components of the main landing gear retraction system lacked recent lubrication. Several retraction components utilize grease fittings to apply proper lubrication of movable gear components. The grease fittings on the airplane’s main landing gear had been painted over, and there was no evidence of grease on the movable parts. The landing gear’s ball joints and movable surfaces all appeared dry.