Mapleton, ME, USA
N5168E
CESSNA A185F
During a cross-country flight at an altitude of about 2,500 feet mean sea level and about 5 nautical miles from the destination airport, the pilot observed a sudden decrease in engine power. After activating the high-power fuel boost pump setting and subsequently switching fuel tanks, the pilot performed a forced landing to a nearby field; the boost pump remained activated for the rest of the flight. During the landing, the airplane collided with trees, resulting in substantial damage to the fuselage and right wing. Fuel normally flows by gravity from each wing’s fuel tank to a three-position selector valve. The selector valve then allows fuel flow from either the left wing tank, the right wing tank, or both tanks simultaneously. A postaccident examination of the airplane revealed no fuel in the right wing tank, 10 to 12 gallons of fuel in the left wing tank, and unobstructed fuel lines from the left wing tank to the fuel selector. A visual engine examination and engine test run with fuel supplied directly to the fuel selector revealed no engine operating anomalies, indicating that the pilot likely had the right fuel tank selected when the engine first lost power. When the pilot attempted to regain engine power, he left the auxiliary fuel pump activated for the rest of the flight, well beyond the 3- to 5-second interval dictated by the airplane’s engine restart procedures, which likely resulted in the engine flooding.
On July 22, 2012, about 1430 eastern daylight time, a Cessna A185F, N5168E, was substantially damaged following a partial loss of engine power and collision with terrain in Mapleton, Maine. The private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight, which was operated under the provisions of 14 Code of Federal Regulations Part 91. The flight originated at a private airstrip in Ashland, Maine about 1330, and was destined for Presque Isle Airport (KPQI), Presque Isle, Maine. According to the pilot, he departed with about 26 to 28 gallons of fuel onboard for the one hour flight to PQI, where he intended to refuel the airplane. While flying north of PQI at an altitude between 2,500 and 3,000 feet mean sea level and an engine power setting of 2,500 rpm, the pilot noticed a sudden decrease in engine power that sounded like the engine was being “throttled back.” At the time, he observed that the right wing fuel tank indicated a “very low” fuel level and the left tank fuel gauge indicated about one-quarter tank full. According to a Federal Aviation Administration (FAA) inspector, the pilot initially reported having the fuel selector on the left tank. After the loss of engine power, the pilot switched to the right tank and activated the fuel boost pump. The engine appeared to regain some power, but lost power shortly after at which point the pilot placed the fuel selector in the “Both” position. In his statement to the NTSB, the pilot noted that after the initial power loss, he turned the fuel selector from the “Both” setting to the left tank position, activated the high power setting of the fuel boost pump and then rotated the fuel selector to the right tank setting. The boost pump remained engaged and in the high power setting for the remainder of the flight. After observing the engine continue to produce low power, the pilot performed a forced landing in a field. During the landing, the airplane collided with trees, resulting in substantial damage to the fuselage and right wing. An FAA inspector examined the airplane at the scene, which was located about 2 nautical miles north of PQI. The inspector confirmed substantial damage to the airframe and fuel in the left wing tank, but could not verify fuel in the right tank due to its inaccessibility. An examination of the left and right tank fuel vents revealed no obstructions. According to the pilot, 3 days after the accident, the airplane was recovered from the trees and about 10 to 12 gallons of fuel were drained from the left wing tank while the right wing tank was empty. According to a mechanic, neither wing tank had been breached. The fuel bowl and selector were drained, and no evidence of contamination was noted. There was also no evidence of contamination of the fuel tanks and screens. An external fuel tank was connected directly to the fuel selector and a propeller was installed on the engine. The engine was started and allowed to warm up for 2 to 3 minutes before tests were conducted. A magneto check revealed no anomalies. The engine was run for approximately 15 minutes at various power settings, during which, it accelerated without hesitation and ran smoothly. Unobstructed fuel flow was confirmed from the fuel tanks to the fuel selector, which was operated through its full range with no anomalies. After the engine run, a subsequent examination revealed no abnormalities with the spark plugs or engine fuel filter bowl. The pilot held a private pilot certificate and had accumulated about 430 hours total flight time, of which 202 hours were in the accident airplane make and model. His most recent third class FAA medical certificate was issued on September 9, 2010. The 1845 automated weather observation at PQI included winds from 220 degrees at 10 knots with gusts to 15 knots; visibility 10 statute miles; broken cloud layers at 7,000 feet and 8,000 feet; temperature 27 degrees Celsius (C); dew point 13 degrees C, and an altimeter setting of 29.95 inches of mercury. The airplane was manufactured in 1979, and was equipped with a Continental IO-520-D, 300-horsepower reciprocating engine, and amphibious landing gear. According to maintenance records, the airplane’s most recent annual inspection was completed on May 12, 2012. The airframe had accrued a total time of 3,437.4 hours and the engine had accrued a total time of 3,382.2 hours at the time of inspection. According to the description of the Cessna A185F fuel system found in the pilot’s operating handbook, “Fuel flows by gravity from the two wing tanks to a three-position selector valve labeled LEFT TANK, RIGHT TANK, AND BOTH ON. With the selector valve in the LEFT TANK, RIGHT TANK, or BOTH ON position, fuel flows through an accumulator tank, fuel shutoff valve, fuel strainer and through a bypass in the auxiliary fuel pump (when it is not in operation) to an engine-driven fuel pump. The engine-driven fuel pump delivers the fuel to the fuel control unit where it is metered and directed to a manifold which distributes it to each cylinder. Vapor and excess fuel from the engine-driven fuel pump and fuel control unit are returned by way of a vapor return lie to an accumulator tank and to both wing tanks.” Air start procedures for the Cessna A185F in accordance with the pilot’s operating handbook included: “To ensure a prompt engine restart after running a fuel tank dry, immediately switch to a tank containing fuel at the first indication of fuel pressure fluctuation and/or power loss. Then place the right half of the auxiliary fuel pump switch in the “ON” position momentarily (3 to 5 seconds) with the throttle at least ½ open. Excessive use of the auxiliary fuel pump at high altitude and full rich mixture can cause flooding of the engine as indicated by a short (1 to 2 seconds) period of power followed by a loss of power. This can later be detected by a fuel flow indication accompanied by a lack of power. If flooding does occur, turn off the auxiliary fuel pump switch, and normal propeller windmilling should start the engine in 1 to 2 seconds.”
The pilot’s improper fuel management, which resulted in fuel starvation and a total loss of engine power, and his use of an improper engine restart procedure.
Source: NTSB Aviation Accident Database
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