Incident Overview
An airport attendant at Peter O. Knight Airport in Tampa, Florida, reported hearing a radio transmission in which a pilot stated that his airplane's engine was experiencing roughness and backfiring. Shortly after the initial call, the attendant heard the pilot say, "we're not going to make it." The airplane subsequently ditched in Tampa Bay, approximately one-third of a mile short of the airport, coming to rest in about 16 feet of water.
Examination Findings
Postaccident examination of the airframe, flight controls, and engine revealed no anomalies. However, a detailed inspection of the Teledyne Continental Motors dual-drive magneto showed that the magneto's cam had lost all lubrication and that the points were seized.
Maintenance Records
Airplane records indicated that the last known magneto overhaul was performed by Electrosystems, Inc. in October 1997. The magneto was reinstalled on July 21, 2003, during an engine overhaul, but the magneto itself was not overhauled at that time. Teledyne Continental Motors Service Bulletin SB643B, which applies to the subject magneto, specifies that the magneto should be overhauled when the engine is overhauled. Additionally, Textron Lycoming's Mandatory Service Bulletin requires mandatory parts replacement at overhaul and during repair and normal maintenance.
Fuel Flow Divider
Examination of the Bendix Fuel Flow Divider installed on the accident airplane revealed that it did not have the latest diaphragm installation, as specified in Bendix Fuel Systems Service Bulletin RS-86, dated December 23, 1983.