On December 8, 1996, at 1230 eastern standard time, a Cessna 421C, N5195C, collided with the ground during an emergency landing attempt a mile southeast of the Clearwater Airport in St. Petersburg, Florida. The personal flight operated under the provisions of Title 14 CFR Part 91 with no flight plan filed. Visual meteorological conditions prevailed at the time of the accident. The airplane sustained substantial damage. The pilot received serious injuries and the two passengers received minor injuries. The flight departed St. Petersburg, Florida at 1225. Shortly after takeoff, the pilot experienced a rough running right engine and a subsequent total loss of right engine power. The pilot elected to return to the airport for an emergency landing on runway 09. The pilot stated he immediately shut down the right engine and feathered the propeller. The tower advised him that runway 09 was closed and would have to land runway 35. After entering a downwind for 35, the pilot realized that he was unable to make the runway. He was then directed to land runway 04. He lost a significant amount of altitude through this maneuvering and subsequently collided with some trees and the ground. Service Bulletin, CSB 94-4, was issued on June 13, 1994, regarding starter adapter shaftgear and crankgear inspections. This bulletin required inspection and/or replacement of the starter adapter and crankshaft gear teeth, of the TCM GTSIO-520 model engines. Compliance with this bulletin is required to prevent possible failure of the starter adapter shaftgear and/or crankshaft gear which can result in engine failure and/or metal contamination. Service Bulletin, CSB 94-4, was complied with, by installing a new starter adapter, part number 643259A17 and crankshaft gear. Teledyne Continental Motors personnel performed a tear down of both engines. According to their Analytical Inspection Report, of the right engine, "Viewing the dowel holes of the starter adapter you can see marks that indicate the adapter was not straight when it was installed. If the adapter is not installed straight, the front pilot shaft could damage the needle bearing upon installation. The starter adapter needle bearing was broken up and the starter adapter shaft moved around, mutilating the needle bearing bore, contaminating the engine lubrication system with debris. Debris damaged and held the oil pressure relief valve off its seat allowing oil to bypass within the oil pump, and not supply oil flow downstream, which caused oil starvation to the engine." The number of hours accumulated on the engine, since Service Bulletin compliance, has not been determined.