On April 2, 2003, at 1357 Pacific standard time, a Cessna T210L, N701TM, in the process of being re-registered, and being operated/flown by a private pilot, sustained substantial damage during ditching approximately one mile west of the Tacoma Narrows airport, Gig Harbor, Washington. Visual meteorological conditions prevailed and no flight plan had been filed. The flight, which was a maintenance test flight, was operated under 14 CFR 91, and originated from the Tacoma Narrows airport, approximately 1340. The pilot reported that he departed in the aircraft from Tacoma Narrows on a check flight due to a previous power loss event. He indicated that the aircraft was inbound back to the airport when he experienced an abrupt and total loss of power. He activated the fuel boost pump and power returned for approximately 10 seconds and then the engine quit again. He then switched fuel tanks, activated the boost pump and the engine started and ran approximately three seconds and then quit. He reported that the fuel pressure dropped to about 4-5 PSI during each power loss and returned to its normal reading each time the engine restarted. He reported that the aircraft had about one-third to one-quarter fuel in each wing tank. The pilot executed an intentional ditching along the shoreline about one mile west of the airport and in about three feet of water (refer to NTSB Form 6120.1). The aircraft was recovered and then the engine/fuel system was examined on April 4, 2003, under the oversight of an inspector from the Federal Aviation Administration's (FAA) Renton Flight Standards District Office (FSDO). Among the findings noted during this examination were: > No fuel in the main wing tanks (previously drained during recovery). > A mix of fuel/salt water was found in the left header (reservoir) tank. > Fuel was found in the right header (reservoir) tank. > Uncontaminated fuel in both the fuel strainer, fuel hoses and fuel flow divider. > A basic compression and continuity check was successfully accomplished. > The turbocharger was found to be free to rotate. > The turbocharger inlet hose internal spring was found separated allowing the hose to collapse and this condition could not be determined to pre-exist the ditching event. > After inserting approximately 10 gallons of fuel in both left and right tanks the main fuel line to the engine was decoupled at the firewall and no fuel was observed to gravity flow out when left or right tank was selected at the fuel selector. The fuel line was disconnected at the outflow side of the auxiliary fuel pump and fuel was observed to flow. The fuel line was then reconnected to the auxiliary pump and fuel was observed to flow freely at the decoupled firewall fitting end. > The auxiliary pump was exclaimed and no discrepancies were found. > The fuel venting system was examined and no discrepancies were found. The aircraft's engine was test run on April 8, 2003, under the oversight of the same FAA inspector. Aside from a slightly rich mixture condition, the engine appeared to run satisfactorily (refer to ATTACHMENTS ROI-I, AA-I, and DIAGRAM I).