On November 4, 1994, about 1941 eastern standard time, a Cessna 310L, N216Y, registered to Twonesix Yankee, Inc., went off the runway when the landing gear collapsed during landing at Kendall-Tamiami Executive Airport, Miami, Florida, while on a 14 CFR Part 91 positioning flight. Visual meteorological conditions prevailed at the time and an instrument flight rules flight plan was filed. The aircraft received substantial damage and the commercial-rated pilot was not injured. The pilot-rated passenger received serious injuries. The flight originated at Kendall-Tamiami Executive Airport on November 4, 1994, about 1700. The pilot stated that after takeoff from Kendall-Tamiami Executive Airport the tower reported that the left main landing gear appeared to still be down. He lowered and retracted the landing gear again and the tower reported the left main gear was still extended. The pilot-rated passenger read the emergency gear extension checklist and he attempted to perform a manual gear extension. This was unsuccessful. The pilot-rated passenger also attempted to manually lower the gear, with no success. After several hours of flying around the airport to burn fuel he began to smell an odor similar to that of a wire burning. The instrument lights quit, and the leftengine manifold pressure gauge began to fluctuate. He then returned to the airport for landing. On touchdown the aircraft veered to the right and went off the right side of the runway where it came to rest in the grass. After exiting the aircraft the passenger fell in the grass and injured her ankle. The mechanic who gave assistance to the pilot over the radio prior to landing, and who later recovered the aircraft, stated he initially observed the aircraft with the left main gear down and the right main gear and nose gear up. When the aircraft landed the left main gear and nose gear were down. The right main gear was extended about midway between the up and down position. When the aircraft was raised by a crane after the accident the mechanic used the manual extension system to lower and lock all three landing gear. Examination of the aircraft by NTSB and FAA inspectors revealed the left and right main gear retraction and extension linkages were broken at the point they attach to the respective landing gear. A replacement linkage was installed on each main landing gear. The aircraft was placed on jacks and the manual extension system was used to raise and lower the landing gear. Each landing gear moved freely. The landing gear transmission and all linkages operated normally. The electric gear motor was not used due to damage to the aircrafts electrical system. Examination of the left engine revealed the exhaust pipe at the no. 4 chlinder had cracked at a weld repair allowing exhaust gases to leak. The nos. 2 and 4 rocker box covers had been partially burned away and the no. 2 intake valve had stuck due to heat damage. Electrical wiring from the left engine generator had been burned. Examination of the aircraft indicated the left main landing gear attach structure was bent. The nose and nose wheel well structure was bent. The right wing leading edge structure was bent near the tip fuel tank. The accident was reported to NTSB shortly after it occurred. Initial reports from FAA indicated the aircraaft had sustained minor damage and that the passenger had sustained minor injuries. On November 30, 1994, the passenger called NTSB and reported she had sustained serious injury to her ankle.