HISTORY OF FLIGHT On July 10, 2004 at 0920 eastern daylight time, a Cessna 401B, N7983Q, registered to and operated by Parrot Air, LLC right landing gear collapsed during landing roll on runway 14 at Naples Municipal Airport, Naples, Florida. The flight operated under the provisions of Title 14 CFR Part 91. Visual meteorological conditions prevailed at the time of the accident and no flight plan was filed. The airplane was substantially damaged. The pilot, pilot rated passenger and other passengers were not injured. The flight originated from Key West International Airport, Key West, Florida, on July 10, 2004 at 0850. The personal flight from Key West to Naples was uneventful, however, the pilot stated that during landing roll, there was a vibration that felt like a "wheel shimmy condition". According to the pilot, as the airplane crossed the intersection of runway 14 and runway 23, the airplane became "light". As the pilot attempted to maintain control of the airplane, the right wing collided with the runway and the airplane slid to the right and came to a stop in the grass on the south side of the intersection of runway 14 and taxiway "A", about 2,650 feet from the approach end of runway 14. PERSONNEL INFORMATION Review of information on file with the FAA Airman's Certification Division, Oklahoma City, Oklahoma, revealed that the airman held a private pilot certificate with ratings for airplane single engine land, airplane multiengine land and instrument airplane. His pilot certificate was issued on May 25, 2004. The review of medical records on file with the FAA revealed the pilot held a third class medical certificate issued on January 28, 2004 with the limitation that the pilot must wear corrective lenses. The pilot reported having a total flight time of 607 hours with 31.4 hours in a Cessna 401B. Review of information on file with the FAA Airman's Certification Division, Oklahoma City, Oklahoma, revealed that the co-pilot held a commercial pilot certificate with ratings for airplane single engine land, airplane multiengine land and instrument airplane. His last biennial flight review at the time of the accident was February 19, 2004 in a Piper Aztec, PA 23-250. The review of medical records on file with the FAA revealed the co-pilot held a third class medical dated August 2002 with the limitation that he must wear corrective lenses. The co-pilot reported having a total flight time of 1,393 hours with 115 hours in a Cessna 401B. AIRCRAFT INFORMATION The airplane was a fixed wing, multiengine, 1971 Cessna 401B. It's maximum gross weight was 6,210 pounds and it had 7 seats installed. The airplane was equipped with two TSIO-520E reciprocating, 300 horsepower engines manufactured by Teledyne Continental Motors. The last recorded annual inspection was conducted on December 1, 2003. The airframe total time was 6,320.3 hours and there was 31.4 hours recorded since that last inspection. METEOROLOGICAL INFORMATION The weather reporting facility was at the Naples Municipal Airport in Naples, Florida. The 1353 Zulu surface weather observation was: winds variable at 03 knots, visibility 10 statute miles, cloud condition clear, temperature 29-degrees Celsius, dewpoint 25-degrees Celsius, and altimeter 30.10 inches of mercury. Visual meteorological conditions prevailed at the time of the accident. WRECKAGE AND IMPACT INFORMATION The post-accident examination of the airplane revealed damaged to the propeller, a broken drag brace, the left flap bent upwards, damage to the underbelly of the fuselage, the right main gear collapsed and the right elevator tip scraped. Also, the right wing inboard was bent, right aileron was damaged and right flap and right wing rear spar was damaged. The pilot did not report any mechanical malfunctions with the airplane prior to the accident. Further examination of the right landing gear assembly revealed that the down lock adjustment stud was broken. A visual examination of the stud fracture face disclosed that approximately 3/4 of the fracture face appeared to be old, and 1/4 of the fracture face appeared to be a fresh fracture. The maintenance history of the down lock adjustment stud was not determined nor was subsequent efforts to secure the fractured stud for further examination successful.