History of Flight
On August 23, 2011, at 0940 Pacific daylight time, a Beech A23-24, registration N5779V, experienced a total loss of engine power. The Certified Flight Instructor (CFI) landed the airplane on a dirt road approximately 2 miles north of Palo Alto Airport, Palo Alto, California. The CFI and a student pilot were operating under Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. The local instructional flight had originated at Palo Alto Airport around 0830.
The day before the accident, the student pilot, who owned the airplane, reported that they had filled the tanks to 40 gallons and conducted a flight lasting between 1.5 and 2.0 hours. During preflight on the accident day, they observed the right tank fuel level at the tab (15 gallons) and the left tank well below the tab, estimating 10 gallons remaining. They took off with the right tank selected, performed touch-and-goes, and about 50 minutes into the flight, the student switched the fuel selector to the left tank. Ten minutes later, while on the upwind leg at 400 feet above ground level, the engine lost power completely. The CFI took control, established best glide speed of 79 knots, and landed on a narrow dirt road. During the landing, the left wingtip struck a small tree, causing the airplane to veer left off the road into tall grass.
Post-Accident Examination
A Federal Aviation Administration inspector examined the airplane on scene and observed a small amount of fuel in the left tank and fuel in the right 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 four cylinders. The gascolator screen was clear of debris. The fuel selector moved freely and seated in each detent. The master switch was activated, and the fuel boost pump motor was heard operating. During recovery, 12 gallons of fuel were drained from the right tank and approximately 2 cups from the left tank.
Personnel Information
The CFI, aged 36, held a commercial pilot certificate with airplane single-engine land and instrument ratings, and a flight instructor certificate with an airplane single-engine land rating. He had 620 hours of total flight time and 280 hours of dual instruction given. The student pilot, aged 30, held a third-class medical certificate and reported 30 hours of total flight time, most accumulated within the previous 90 days.
Aircraft 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, equipped with a McCauley fixed-pitch propeller. Total airframe time was 3,563 hours, and the last annual inspection was performed on December 14, 2010. The engine had 240 hours since overhaul.
Tests and Research
On September 13, 2011, the NTSB investigator-in-charge examined the airplane. The wings had been removed, but there was no evidence of fuel tank breach or fuel line leakage. The fuel selector rotated smoothly and clicked into each detent. The gascolator was clear. An external fuel reservoir was attached to both tank lines, and fuel drained from the gascolator when either tank was selected; no fuel drained when the selector was off. The engine started and ran successfully at 2,250 rpm for 2 minutes on each tank. Both magnetos were isolated, and a 250 rpm drop was observed when switching from BOTH to LEFT or RIGHT. The engine idled smoothly at 1,200 rpm.
Fuel usage calculations were performed. The Beechcraft Pilot Operating Handbook indicates at 75% power fuel flow is 12.3 GPH, and at 65% power 9.4 GPH. A Beechcraft technical representative noted that landing pattern operations approximate 65% BHP fuel flow. Using conservative estimates, the previous day's flight of 1.5–2.0 hours would have used 16.2–21.6 gallons, and the accident day's 1-hour pattern flight used about 9.4 gallons, totaling 25.6–31.0 gallons. Starting with 40 gallons and subtracting the 12 recovered yields 28 gallons used, which falls within that range.