Cessna Stationair/Turbo Stationair 6
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor
Flight Crew Last 90 Days 100; Flight Crew Total 3000; Flight Crew Type 75
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Ground Strike - Aircraft; Ground Event / Encounter Person / Animal / Bird; Inflight Event / Encounter Fuel Issue
Air Traffic Control Provided Assistance; Aircraft Aircraft Damaged; Flight Crew Took Evasive Action; Flight Crew Landed in Emergency Condition; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft; Procedure
At 8;000 ft. on a cross country flight from ZZZ to ZZZ1 the engine lost full power but was returned to operational power by switching tanks; adjusting mixture; using aux fuel pump and the emergency fuel pump. ATC questioned the loss of altitude and after dealing with the situation I explained the situation and that I had returned to normal flight and no assistance was necessary.A placard inside of the aircraft advises that in the event of a major fuel flow fluctuations/power surges to.1. Aux fuel pump on and adjust mixture2. Select opposite tank.3. when fuel flow steady; RESUME NORMAL OPERATIONSApproximately an hour after this event (after switching fuel tanks back and forth to and from the original tank which the engine lost power on) the fuel flow dropped and the engine quit again. This time I was at 10000 ft. MSL and was unable to reestablish fuel flow and restart the engine. [I Requested Priority Handling]; I navigated the aircraft to the nearest airport with the help of ATC and after exiting the clouds at 300 ft. AGL flew under a set of power lines; over a barbed wire fence (the main landing gear caught the barbed wire and damaged the fence) then landed on the airport however not on the runway. The gear sunk into the mud; the nose wheel broke off; the airplane tipped on its nose then settled back onto the main landing gear and came to a stop.I believe this to be a fuel related issue. According to my flight planning I had plenty of fuel; additionally the fuel monitor in the aircraft; the fuel gauges and the fuel planning function of the gps system all agreed that there was plenty of fuel on board.The problem seems to be related to vapor lock which I had read about just prior to departing in the aircraft. My reaction was 'If its known about and there's an emergency fuel pump and placarding for it then it can't be a big deal.' If the placard had not read 'resume normal operations' I would have discontinued flight and landed appropriately and had the issue fixed.
Pilot reported recurring fuel problems resulting in engine power loss; causing a rough landing and aircraft damage from landing off the runway.