N6599S

On June 20, 1997, approximately 1320 Pacific daylight time, a Cessna 150H, N6599S, crashed during a forced landing attempt following a loss of engine power east of Sweet Home, Oregon. The aircraft was substantially damaged, the private pilot (who owned the airplane) was uninjured, and a passenger received minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the local 14 CFR 91 flight from Sweet Home.

An FAA inspector from Hillsboro, Oregon, who responded to the accident site, reported that he found only about 1 1/2 gallons of fuel in the accident aircraft. The FAA inspector did not report finding any evidence of an inflgiht fuel leak or engine malfuction in the wreckage. The pilot subsequently reported the accident to the NTSB as follows:

I had flown from Sequim, [Washington] to Renton[,Washington] and then on to Sweethome [sic]...I added 5 1/2 [gallons] of fuel to the left wing (Autofuel) using a can I regularlyuse....I dipped the tanks [and] measured 8 1/2 [gallons in the left] wing and 7 1/2 in [the right]...more than 2 [hours fuel on board]...[I] advised [the passenger] that we would return in 1 to 1 1/2 [hours]...we launced to the west and circled my folks and her new home and took photos (1/2 mile east of field)....then climbed to 9000 [feet] as we headed East to circle the 3 Sisters mountains. Circled [and took] photo [and] return[ed]....at 4-5 [miles] out...the engine died. I used full carb heat, full rich, [pumped] throttle [and] cycled carb heat. [No] effect. I felt we could make the field - pulled nose up [and] stopped prop. Then held 70 MPH for several [minutes. At approximately] 2 [ miles] from [runway I] realized we might not make it...did a 180 [degree] turn to my [second] choice "field" down to treetop level - pulled up over a power line I had not seen earlier and [dodged] trees - "landed" and hit an 8 [foot] high wild blackberry patch, a 2 [foot] embankment, plane spun 250 [degrees] and stopped on [centerline] of a 2 lane roadway.

On his NTSB accident report, the pilot stated that he had been unable to find evidence of an inflight fuel leak, and speculated that "I must have misread the fuel dip stick." (NOTE: The FAA inspector assigned to the accident reported that he examined this dipstick, and that it was homemade.) In response to a request by the NTSB investigator-in-charge (IIC) to provide the last fueling receipt or other record documenting the last refueling, the pilot responded that he was unable to provide such a record "as I regularly use Autofuel in the plane." The pilot stated that he has two 5 1/2 gallon polyethylene jugs that are normally used, that he filled the plane at Sequim on June 19, 1997 before departure, and that he checked the fuel quantity at Renton. He stated that the fuel quantity at Renton was 21 gallons, although he had not written this down. The pilot stated that he took off from Sweet Home at 1208 and crashed at 1320, 1 hour and 12 minutes after takeoff.

Straight-line distances to the accident were determined by chart measurement as follows: Sequim Valley Airport to Renton Airport, 55 nautical miles; Renton Airport to Sweet Home airport, approximately 185 nautical miles; Sweet Home Airport to South Sister Mountain (elevation 10,358 feet), 43 nautical miles; South Sister Mountain to North Sister Mountain (elevation 10,085 feet), 4 nautical miles; and North Sister Mountain to Sweet Home Airport, 42 nautical miles.

The Cessna 150H owner's manual states that the airplane may be equipped either with standard fuel tanks with 22.5 gallons total usable capacity (plus 3.5 gallons unusable), or long range tanks with 35 gallons total usable capacity (plus 3 gallons unusable.) Cessna Aircraft Company reported that according to its manufacture records the accident aircraft was delivered with standard fuel tanks. The owner's manual gives cruise performance at 7,500 feet ranging from 77 MPH (67 knots) true airspeed (TAS) at 3.2 gallons per hour fuel burn (at 2,200 RPM/40% power), to 117 MPH (102 knots) TAS at 5.5 gallons per hour fuel burn (at 2,700 RPM/74% power.) At 10,000 feet, the owner's manual indicates cruise performance as being from 82 MPH (71 knots) TAS at 3.3 gallons per hour (at 2,300 RPM/42% power), to 116 MPH (101 knots) TAS at 5.1 gallons per hour (at 2,700 RPM/68% power.) The owner's manual cruise performance data is based on lean mixture. At 7,500 feet, 2,600 RPM yields 66% power, at 111 MPH (97 knots) TAS and 4.9 gallons per hour. At 10,000 feet, 65% power is at approximately 2,650 RPM, at about 113 MPH (98 knots) TAS and 4.9 gallons per hour.