Primary finding
Probable cause
The pilot's improper fuel planning, which resulted in a loss of engine power due to fuel exhaustion.
Investigator assessment
Analysis narrative
The pilot was ferrying the airplane from Washington to Alaska. About 40 minutes into the sixth leg of the trip, the airplane's engine lost all power, and the pilot made a forced landing to a tree-covered field, sustaining substantial damage to the wings, fuselage, and empennage. A review of the pilot's fueling receipts, along with the flight times on each of the legs, revealed that the engine was consuming an average of 14.6 gallons per hour (gph) of fuel during the first four legs of the trip. On the next leg, the fuel consumption rose to an average of 17.13 gph. The airplane had flown a total time of 3:10:48, from the time the pilot last refueled. According to the airplane manufacturers cruise and range performance charts, if flown in accordance with the notes on the chart, the airplane should have had enough fuel to fly between four and five hours. However, if the most recent calculated actual fuel burn of 17.13 gph was used, the airplanes fuel endurance would have been about 3 hours 12 minutes. Given the pilot's statement that he did not lean the fuel mixture during the leg before the accident leg, the calculated fuel consumption on that leg, and the absence of fuel found in the fuel tanks postaccident, it is likely that the engine was using considerably more fuel than the pilot had calculated by the performance charts. The investigation was unable to determine if the unattached fuel bladder fasteners would have an effect on fuel quantity. Also, given the lack of anomaly during the test engine run, it is likely that the engine lost power due to fuel exhaustion.
Source record
Factual narrative
On July 31, 2012, about 1000 Alaska daylight time, a Cessna 182B airplane, N7150E, sustained substantial damage during a forced landing, following a loss of engine power, near Gakona, Alaska. The private pilot sustained minor injuries, and the sole passenger sustained serious injuries. The flight was being operated as a visual flight rules (VFR) personal cross-country flight under the provisions of 14 Code of Federal Regulations Part 91 when the accident occurred. Visual meteorological conditions prevailed, and a VFR flight plan was filed and active. The flight originated at Northway, Alaska about 0910, and was destined to Gulkana, Alaska. In an interview with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on August 2, the pilot stated that he had just purchased the airplane, and was ferrying it from Washington to Alaska. He said he refueled the airplane the previous night in Whitehorse, British Columbia, Canada. He flew from Whitehorse to Northway, where he cleared Customs, and then continued on toward Gulkana. About 40 minutes into the flight, the engine began to lose power. He switched the fuel selector valve to different positions, and was able to briefly regain engine power. The engine lost power a second time, and the pilot elected to make a forced landing, but had insufficient altitude to reach a highway, and landed in a tree-covered field. The airplane sustained substantial damage to the wings, fuselage, and the empennage. On August 1, an airworthiness inspector from the Federal Aviation Administration Fairbanks Flight Standards District Office examined the wreckage at the accident site. The right wing was severed at the wing root attach points, and folded back alongside the fuselage by the impact. The left wing was still attached to the fuselage which was mostly intact. Sumping of the airplane's fuel tanks revealed only a small amount of residual fuel in both fuel bladder tanks. On August 7, the NTSB IIC, along with representatives of Cessna Aircraft Company, and Continental Motors Inc., performed a test run on the accident engine at the facilities of Alaska Claims Services, Wasilla, Alaska. The engine remained attached to the fuselage, and fuel was introduced to the engine through the left wing fuel inlet line. The engine started without hesitation or stumbling, and ran to full throttle. No anomalies were noted that would have prevented normal operation and production of rated horsepower. Examination of the wing fuel bladders showed that both the left and right bladders were collapsed on the outer ends. The right bladder outboard upper fasteners were loose in the tank cavity; not attached to the bladder. The left wing fasteners were attached to the bladder but were not snapped into the upper cavity receptacles. Also, the fastener receptacles (several) had repairs done to them. The fasteners did not look like the correct size/shape/grip length. A review of fueling receipts provided by the pilot, along with his flight times, and Global Positioning System (GPS) data from a handheld unit in the airplane, showed that the engine was using approximately 14.6 gallons per hour (gph) of fuel on the first three legs of the trip. On the fourth leg, from Watson Lake, British Columbia, Canada, to Whitehorse, the engine averaged 17.13 gph. Data retrieved from the GPS onboard the airplane showed that the flight from Whitehorse to Northway took 2:23:08, from startup to shut down. The accident flight from Northway to the accident site showed a time of 0:47:40 from startup to shutdown, for a total flight time since the last refueling of 3:10:48. The pilot stated that he did not lean the mixture on the flight from Whitehorse to Northway, as he was "up and down" with the weather. He said he did lean the mixture on the accident flight, but could not give specifics on his leaning procedures.