On September 10, 2004 at 1730 eastern daylight time, a Piper PA-44-180, N268DA, registered to Jack and Robert Arrow LLC., and operated by the commercial pilot, collapsed the nose and right main landing gear during roll out at the Kendall-Tamiami Airport in Miami, Florida. The personal flight was operated under the provisions of Title 14 CFR Part 91 and visual flight rules. Visual meteorological conditions prevailed and no flight plan was filed. The pilot and two passengers were not injured and the airplane sustained substantial damage. The flight originated at Opa Locka, Florida, on September 10, 2004, at 1715. According to the pilot, when he lowered the landing gear during his approach he verified that he had three green lights and the nose gear was visible in the mirror, and the red gear unsafe warning light was off. When he turned onto final approach and lined up with the runway he again checked and found that he had three green lights and verified the nose gear was visible in the mirror. He said he touched down on runway 9R and began the rollout. After about five seconds, he applied brakes to make the first turn off. Immediately after applying the brakes, he said the landing gear collapsed. The airplane slid down the runway veered to the right and came to a stop just off the side of the runway, damaging the right outboard wing, the under carriage and propeller. Examination of the airplane found the flaps extended about 10 degrees and the gear handle not fully down in its detent. The airplane was moved to a maintenance facility on the airport and the gear was actuated seven times. The gear order of operation was first left main down and locked, second right main down and locked, then the nose gear down to 3/4 travel at which time the right main will unlock and brake over center and both nose and main will then lock. Each time the landing gear functioned normally, there was no damage noted to the gear locks or the squat switch.