SEA97LA017

On October 17, 1996, approximately 1820 mountain daylight time, a Cessna 182Q, N5117N, registered to the Civil Air Patrol (CAP), experienced a loss of engine power while inbound to the airport at Pocatello, Idaho. The airplane flipped over in a forced landing attempt in a field 5 miles northeast of Pocatello and was substantially damaged. The commercial pilot received minor injuries. The 14 CFR 91 business flight had departed Idaho Falls, Idaho, on a visual flight rules flight plan. Visual meteorological conditions existed at Pocatello at the time of the accident.

An FAA inspector who responded to the accident reported that the pilot had flown several legs prior to the accident flight and had not refueled the aircraft during any of the en route stops. He reported that in an examination of the aircraft wreckage, both wing tanks were found empty and no fuel was found in the gascolator.

The pilot provided a comprehensive statement including departure and arrival times, and fuel remaining on board the aircraft for each of four legs (Pocatello to Idaho Falls; Idaho Falls to Nampa, Idaho; Nampa to Idaho Falls; and Idaho Falls to Pocatello.) The pilot stated that he used a calibrated dipstick to check the fuel prior to departure from Pocatello (71 gallons at departure), at Nampa (39 gallons remaining), and at Idaho Falls (19 gallons) on the return flight. The accident aircraft had a fuel capacity of 92 gallons, with 88 gallons usable.

From the pilot's records, total fuel consumption for the first two legs (Pocatello-Idaho Falls-Nampa) was 32 gallons. Usable fuel on board at departure from Nampa was 35 gallons (39 gallons, as reported by the pilot, minus 4 gallons unusable) for the return flight with the same routing. The elapsed time for the return leg from Nampa to Idaho Falls was 93 minutes, as opposed to the outbound time of 111 minutes, due to higher ground speed.

The pilot was observed by line personnel when he checked his remaining fuel supply at Idaho Falls prior to the 42-mile return flight to Pocatello. The pilot stated that he used a calibrated dipstick to check the fuel prior to his last departure on the return flight. The pilot stated that the fuel remaining at that time was 19 gallons (7 gallons in the left tank and 12 gallons in the right tank.) An inquiry to a safety officer of the Idaho Wing of the CAP, which operated the aircraft, revealed that the dipstick used by the pilot (which was normally kept in the aircraft) was homemade and not commercially produced. The calibration accuracy of the homemade dipstick was not determined or reported.

No mechanical discrepancies were found during the investigation. No consideration was made by the pilot concerning the accuracy of the dipstick calibration and the effects upon the indicated fuel quantity of static pitch attitude of the aircraft on the ramp.

According to aircraft maintenance records, the accident aircraft had a zero-time engine installed on October 11, 1996 (six days before the accident) and, according to the records and the pilot's statement, was operating on "break-in" or mineral oil at the time of the accident. Information supplied by the CAP indicated that this trip was the first operation of the accident aircraft since the engine installation, which coincided with an annual inspection of the aircraft.