N2578LPiper PA-38-112 · 1979

On August 22, 2013, about 1227 Pacific daylight time, a Piper PA-38 Tomahawk, N2578L, was substantially damaged during a forced off-airport landing near Madera, California, due to a complete loss of engine power. The certified flight instructor (CFI) and the private pilot under instruction were not injured. The airplane was owned and operated by Mazzei Flying Service of Fresno, California, and the instructional flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed. A Federal Aviation Administration (FAA) flight plan was filed, but not activated, for the flight.

According to the CFI, the private pilot was in the "pre-commercial" phase of his flight training, and the cross-country flight was planned to originate and terminate at Fresno Yosemite International airport (FAT) Fresno, with an intermediate stop at Napa County airport (APC) Napa, California. The pilot also planned to conduct a touch-and-go landing at Livermore Municipal airport (LVK) Livermore, California, on the APC to FAT leg. When the flight was en route to APC, the weather conditions at APC deteriorated below visual flight rules minima, and the pilot decided to divert to Buchanan Field airport (CCR) Concord, California. The landing at CCR was uneventful, and the pilot re-planned the return flight from CCR to FAT. Although fuel was available at CCR, no fuel was taken on at that airport.

The departure and initial phase of the leg from CCR to FAT were uneventful. The pilot did conduct the planned touch-and-go landing at LVK. When the airplane was about 25 miles from FAT, and in the planned descent, the engine ceased developing power. The CFI landed the airplane in a field shortly thereafter. On-site examination by an FAA inspector revealed that neither fuel tank was compromised, and that both fuel tanks were devoid of usable fuel. No other pre-impact abnormalities were reported by the inspector.

Certificated Flight Instructor (CFI)

The CFI held multiple certificates and ratings, including those for flight instructor in a single-engine airplane. He reported a total flight experience of 1,178 hours, including 915 hours in the accident airplane make and model. He reported that he had 117 hours as a flight instructor, of which 100 were in the accident airplane make and model. His most recent flight review was completed in May 2012, and his most recent FAA second-class medical certificate was issued in December 2012.

Pilot Under Instruction

The pilot held a private pilot certificate with an airplane single-engine land rating. He reported that he had a total flight experience of 86 hours, all of which was in the accident airplane make and model. He reported that he had 8 hours as pilot-in-command. His most recent flight review was completed in July 2013, and his most recent FAA first-class medical certificate was issued in July 2012.

FAA information indicated that the airplane was manufactured in 1979, and was equipped with a Lycoming O-235 series engine. According to information provided by the flight school, the airframe had accumulated a total time (TT) in service of 12,413 hours as of its most recent 100-hour inspection, which was completed on August 6, 2013. The engine had a TT of 5,802 hours, including 434 hours since its most recent overhaul. There were no records of any recent problems with the fuel system.

According to the airplane manufacturer's Pilot's Operating Handbook (POH), the airplane was equipped with two fuel tanks, one in each wing. Total fuel capacity was 32 gallons, and total usable fuel was 30 gallons. The fuel selector had three positions, LEFT, OFF, and RIGHT. There was a separate fuel quantity gauge for each fuel tank, but the POH did not specify the graduations or units of the gauges.

The 1253 automated weather observation at Madera Municipal airport (MAE), Madera, located about 5 miles northwest of the accident site, included wind from 300 degrees at 4 knots, visibility 10 miles, clear skies, temperature 31 degrees C, dew point 11 degrees C, and an altimeter setting of 29.87 inches of mercury.

FAA information indicated that the airplane was manufactured in 1979, and was equipped with a Lycoming O-235 series engine. According to information provided by the flight school, the airframe had accumulated a total time (TT) in service of 12,413 hours as of its most recent 100-hour inspection, which was completed on August 6, 2013. The engine had a TT of 5,802 hours, including 434 hours since its most recent overhaul. There were no records of any recent problems with the fuel system.

According to the airplane manufacturer's Pilot's Operating Handbook (POH), the airplane was equipped with two fuel tanks, one in each wing. Total fuel capacity was 32 gallons, and total usable fuel was 30 gallons. The fuel selector had three positions, LEFT, OFF, and RIGHT. There was a separate fuel quantity gauge for each fuel tank, but the POH did not specify the graduations or units of the gauges.

The accident site was about 5 miles southeast of Madera Municipal airport (MAE), which the airplane had just overflown. The site was about 19 miles northwest of the intended destination, FAT. The airplane came to rest upright in a field of low vegetation. All three fixed landing gear were displaced or collapsed. The left outboard wing was crumpled, as were the firewall and the right trailing edge flap. One blade of the two-blade, fixed-pitch metal propeller was bent aft. No pre-impact damage or mechanical deficiencies were noted.

Flight School Fuel Planning Information

The flight school provided several pages of fuel-related flight planning or operational documentation, all of which were normally provided to Mazzei pilots, both students and instructors. The October 2003 Volume I, Issue 1 edition of a document entitled "The Mazzei Standard" stated that "Tomahawks aren't designed to carry two average weight people and a full load of fuel. Please do not top off (fill up) any plane unless you are planning on flying it for an extended period of time. Also, it is inappropriate to tanker extra fuel [italics original] around unnecessarily."

That document also provided three diagrams (for three different fuel level conditions), which allowed pilots to determine the tank's fuel quantity, based on the visual fuel level in relation to an embossed "X" on the aft wall of each fuel tank. A flight school representative stated that this was a flight school, not Piper, method, and that it was derived empirically by adding known quantities of fuel to an empty fuel tank. The diagrams and accompanying text did not cite any airplane attitude requirements for the readings, which could affect the validity of the fuel level and consequent quantity determination.

Another document provided by the flight school contained the guidance that students "shall not depart...without a minimum fuel reserve of 1 hour...calculated at 65% power."

CFI-Provided Information

According to the CFI, he reviewed the pilot's flight planning and pre-flight inspection information, and found it all to be "proper." The CFI reported that he "visually" checked the fuel quantity at FAT before the flight, and determined that the airplane had "exactly" 21 gallons of fuel on board. Before the departure from CCR, the pilot advised the CFI that the airplane had 14 gallons on board, but this time the CFI did not independently verify the fuel quantity.

The CFI reported that at the top of descent into FAT, one fuel gauge indicated "just under" 5 gallons, and the other indicated "exactly" 5 gallons. He also reported that he had personally observed PA-38 fuel gauges provide erroneous quantity information, but that neither he nor his student had any reason to suspect the accuracy of the fuel quantity indications on this airplane. The CFI did not provide any amplifying information on the basis for that confidence.

Once the engine began running rough and losing power during the descent near Madera, the CFI took control of the airplane and attempted to identify the cause of, and rectify, the power loss. He was unable to restore engine power, and he selected the off-airport landing site, and conducted the approach and landing.

Pilot's Flight Planning

The pilot provided copies of his flight planning documents to the investigation; these included one sheet each for the outbound (FAT to APC) leg, and the inbound (CCR to FAT) leg.

For the outbound leg, the pilot's calculated flight time to APC was 83 minutes. His calculated fuel burn for the trip was 9.5 gallons. To that he added a start/taxi fuel of 1.0 gallons, a "Plan B" increment of 0.9 gallons, and a reserve of 3.0 gallons, for a total planned fuel quantity of 14.4 gallons, excluding 2 gallons of unusable fuel.

For the inbound leg, the pilot's calculated flight time from CCR was also 83 minutes. His calculated fuel burn for the trip was 9.6 gallons. To that he added a start/taxi fuel of 0.5 gallons, a "Plan B" increment of 0.3 gallons, and a reserve of 3.0 gallons, for a total planned fuel quantity of 13.4 gallons, excluding 2 gallons of unusable fuel. This plan did not account for the planned (and executed) maneuvering or touch and go at LVK.

According to a flight school representative, the "Plan B" fuel was the fuel needed to fly to the alternate from the original destination, and was not included as part of the separately-calculated "reserve" fuel. The school's policies required that solo students calculate and carry an additional reserve fuel to enable 1 hour of flight at 65 percent power.

The sum of the pilot's first leg fuel burn quantity value of 10.5 gallons (no reserve), plus his second leg required available fuel quantity of 13.4 gallons (including "Plan B" and reserve fuel), yielded an overall required available fuel quantity of 23.9 gallons. Excluding reserves, and not including any additional fuel for the LVK touch and go, the pilot's overall calculated fuel burn quantity was 20.6 gallons.

NTSB Fuel Related Information

The investigation calculated the trip fuel requirements using the pilot's leg times and altitudes, the POH fuel consumption values, and the flight school reserve requirements. The first leg was calculated to burn 8.2 gallons, with a reserve of 5.8 gallons, for an available total of 14.0 gallons. The second leg, not including the LVK touch and go, was calculated to burn 9.0 gallons, with a reserve of 5.8 gallons, for an available total of 14.8 gallons.

The sum of the first leg fuel quantity of 8.2 gallons (no reserve), plus the second leg available fuel quantity of 14.8 gallons (including reserve fuel), yielded an overall required available fuel quantity of 23.0 gallons. Excluding reserves, and not including any additional fuel for the LVK touch and go, the overall calculated fuel burn quantity was 17.2 gallons.

Although the pilot and investigation calculations for the fuel required for each leg were not exactly congruent, the two sets of calculations yielded similar results for the total trip fuel required.

On-Board Fuel Observations

When the airplane was approximately over MAE, the fuel quantity observed by the CFI on cockpit fuel gauges indicated that the airplane had nearly 10 gallons of fuel left, which indicated that only about 4 gallons were consumed since the departure from CCR. That 4-gallon value was less than half of the pilot's planned calculated consumption for that leg. There was no evidence to indicate that either the pilot or the CFI detected or acted upon that discrepancy between the planned fuel consumption and the indicated fuel quantity remaining.

Pilot's Handbook of Aeronautical Knowledge

The FAA Pilots Handbook of Aeronautical Knowledge contained the following guidance regarding cockpit fuel gauges: "Aircraft certification rules require accuracy in fuel gauges only when they read "empty." Any reading other than "empty" should be verified. Do not depend solely on the accuracy of the fuel quantity gauges. Always visually check the fuel level in each tank during the preflight inspection, and then compare it with the corresponding fuel quantity indication."