SEA95LA130

The pilot reported that he departed Challis, Idaho, several days earlier with 54 gallons of usable fuel, and flew approximately 1 hour on the right tank to a remote mountain airstrip. He then returned to Challis, stating that he flew the first 45 minutes of the return flight on the left tank before switching back to the right. The engine ceased operating on final approach, and the pilot executed a forced landing impacting a dirt bank in his ground roll path. Postcrash examination of the aircraft revealed no discrepancies with the airframe fuel system and 2.75 gallons of unusable fuel in the right tank. The engine was subsequently test run and no discrepancies were noted.

On June 25, 1995, approximately 1035 hours mountain daylight time, a Beech P35, N9768Y, being flown by a private pilot, was destroyed during a collision with a dirt bank on landing roll following a loss of power and emergency landing short of runway 16 at the Challis Airport, Challis, Idaho. The pilot sustained serious injuries and the passenger sustained minor injuries. Visual meteorological conditions prevailed and no flight plan had been filed. The flight, which was personal, was to have been operated under 14CFR91, and originated from the Moose Creek USFS airstrip approximately 0930.

The pilot reported departing Salt Lake City at an engine tach time of 4059.61 hours with 54 gallons of usable fuel equally distributed between the left and right wing bladder tanks. The aircraft was flown to Challis, Idaho, (1 hour 45 minutes flight time) where 24.7 gallons of fuel were added to return the total fuel quantity back to the level upon departure from Salt Lake. The aircraft was then flown to Moose Creek USFS on the right tank for a flight duration of approximately one hour.

The pilot reported that several days later he pre-flighted the aircraft, checked the fuel, selected the left fuel tank and departed Moose Creek approximately 0930 on the return flight to Challis. He stated than when about 20 minutes out from Challis "both fuel gages were showing around half full with the right fuel gage indicating slightly more remaining than the left tank" and that "based on this observation, I switched tanks from left to right."

Approximately one hour after departing Moose Creek (about 20 minutes after switching fuel tanks) and while on final approach to runway 16 at Challis at an altitude of 500 feet above ground the engine ceased operating. The pilot reported that he "was more concerned with where we were going to land than with attempting to switch tanks or restart the engine."

The aircraft's left wing impacted a dirt bank which had been built up as a bovine burial site north of the approach end of runway 16 and off airport property (refer to photograph 1).

Post crash examination of the aircraft revealed no airframe fuel system discrepancies and approximately 2.75 gallons of (unusable) fuel within the right wing tank. The integrity of the left wing fuel tank lines was observed to have been compromised. The engine was shipped to the facilities of Teledyne Continental Motors where it was subsequently test run. No discrepancies were noted during the test run (refer to attached reports).