WPR11FA403
WPR11FA403

HISTORY OF THE FLIGHT

On August 23, 2011, at 0940 Pacific daylight time, a Beech A23-24, N5779V, experienced a total loss of engine power and the Certified Flight Instructor (CFI) landed the airplane on a dirt road 2 miles north of Palo Alto Airport, Palo Alto, California. The CFI and student pilot operated the airplane under the provisions of Title 14 Code of Federal Regulations Part 91. The airplane was substantially damaged, and neither the CFI nor student pilot were injured. Visual meteorological conditions prevailed, and no flight plan had been filed. The local instructional flight originated at the Palo Alto Airport around 0830.

The day before the accident the student pilot/airplane owner stated that they had filled the airplane to 40 gallons and conducted a flight that lasted between 1.5 and 2.0 hours. During preflight prior to the accident, they observed that the right tank fuel level was at the tab, which corresponds to 15 gallons, and the left tank was well below the tab, and they estimated that there was 10 gallons of fuel remaining in the left tank. They took off with the right fuel tank selected, performed touch-and-goes, and about 50 minutes in to the flight the student switched the fuel selector to the left tank. Ten minutes later, on the up-wind leg, at 400 feet above ground level (agl), there was a complete loss of engine power. The CFI took control of the airplane, established best glide air speed, 79 kts, landed on a narrow dirt road, and the tip of the left wing struck a small tree causing the airplane to veer left off the road and into tall grass.

A Federal Aviation Administration inspector examined the airplane on scene and reported that a small amount of fuel was observed in the left fuel tank, and fuel was observed in the right fuel tank. There was no evidence of a fuel leak or breach of the fuel tanks. The engine was rotated by hand and thumb compression was achieved on all 4 cylinders. The gascolator screen was examined and was clear of debris. The fuel selector moved freely and the valve would seat itself in each detent. The master switch was activated and the fuel boost pump motor could be heard operating. During the recovery of the airplane, 12 gallons of fuel was drained from the right tank, and 2 cups of fuel were drained from the left.

PERSONNEL INFORMATION

The CFI, age 36, held a commercial pilot certificate issued on August 17, 2009, with airplane single-engine land, and instrument airplane ratings. He held a flight instructor certificate issued on August 12, 2010, with an airplane single-engine land rating. His third-class medical certificate, with no limitations, was issued on October 5, 2010. He reported that he has 620 hours of total flight time, and 280 hours of duel instruction given.

The student pilot, age 30, held a third-class medical certificate, with no limitations, issued on July 20, 2011. He reported he has 30 hours of total flight time, with the majority of that time accumulated within the last 90 days.

AIRPLANE INFORMATION

The four-seat, low-wing, fixed gear airplane, serial number MA-38, was manufactured in 1966. It was powered by a Lycoming IO-360-A2B, 200-hp engine, and equipped with a McCauley fixed pitch propeller. The pilot reported that the airplane had a total airframe time of 3,563 hours at the time of the accident, and the last annual was performed on December 14, 2010. The engine’s time since overhaul was 240 hours.

TESTS AND RESEARCH

On September 13, 2011, the airplane was examined by the NTSB investigator-in-charge. The wings of the airplane had been removed to facilitate aircraft recovery and transportation. There was no evidence of a fuel tank breach or fuel line leakage. The fuel selector rotated smoothly and clicked into place at each detent. The gascolator was clear of debris. In order to facilitate a functional test of the fuel system and engine, an external fuel reservoir was attached to both the left and right fuel tank lines located at each wing root. Fuel was observed to drain from the gascolator when the left or right tank was selected using the fuel selector valve in the cockpit. No fuel was observed to drain from gascolator when the fuel selector valve was in the OFF position. The engine was successfully started and run using this fuel source. It was run for 2 minutes at 2,250 rpm, with the fuel selector positioned on the right tank, then 2 minutes at 2,250 rpm with the left tank selected. Both left and right magnetos were isolated, and a 250 rpm drop was observed when switching from BOTH to LEFT or RIGHT magneto. The engine idled smoothly at 1,200 rpm.

Fuel Usage Calculations.

According to the Beechcraft Musketeer, A23-24, Pilot Operating Handbook, section V, Performance, the following information is provided.

For the fixed pitch propeller on a standard day at 2,500 ft msl, and (2,575 rpm) 75% brake horse power (BHP) fuel flow is 12.3 gallons per hour (GPH). At the same altitude with the engine running at 2,450 rpm (65% BHP) the fuel flow is 9.4 GPH.

Beechcraft technical representative provided the information that for landing pattern operations, a fuel flow equivalent to 65% BHP provides a good estimate of fuel flow. At 2,500 feet msl fuel flow at 2,450 rpm (65% BHP) is 9.4 GPH.

The owner/student pilot stated that they started with 40 gallons of fuel the day before the accident, and flew between 1.5 and 2.0 hours the day before. A conservative fuel flow between 75% - 65% cruise power, would be approximately 10.8 GPH. That value could be applied to the 1.5-2.0 hour flight, and the result would be between 16.2 and 21.6 gallons of fuel used. The next day they flew 1 hour in the pattern, averaging 9.4 GPH, or a total of 9.4 gallons. Total fuel used could be calculated as between 25.6 and 31 gallons combining both flights. Starting with the original 40 gallons and subtract out the 12 gallons that was recovered from the airplane, the result is 28 gallons. Twenty-eight gallons falls between the total amounts of fuel used (25.6 - 31.0 gallons) for the combined flights the pilots flew between the 2 days.

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