Accident Details
On January 20, 2019, at about 1330 central standard time, a Cessna 172P airplane, registration N99308, was substantially damaged during a forced landing near Aguilares, Texas. The pilot sustained minor injuries. The airplane was registered to and operated by Skylens, LLC, conducting an aerial observation flight under Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed; no Federal Aviation Administration (FAA) flight plan was filed for the local flight, which departed Laredo International Airport (LRD), Laredo, Texas, about 0906 and was en route to return to LRD.
Sequence of Events
According to the pilot, she departed with about 40 gallons of fuel, with the fuel selector valve selected for both fuel tanks. During straight and level flight, she switched the fuel selector valve to the slower-burning tank, and after about 2 hours switched it back to both. She monitored the difference in consumption for the remainder of the flight, changing tanks as needed to keep it balanced. Based on experience, she believed full fuel tanks provided about 5.5 hours of flight.
While at an altitude of 5,300 ft mean sea level, the airplane began shaking and the engine rpm dropped to about 900. The pilot moved the fuel selector valve from one side to both and attempted to restore engine power by adjusting the fuel mixture control and the engine throttle control, with no improvement. She pitched the nose down for best glide speed and prepared for a forced landing to a gravel road. During the forced landing, the airplane bounced and veered off the road into a field. As the nose landing gear came down, it stuck in the grass, and the airplane nosed over and came to rest inverted. Both wings and the fuselage were substantially damaged.
Fuel Examination
First responders reported that immediately after the accident, fuel was leaking from the right fuel tank but not the left fuel tank. After the airplane was righted, about 4 gallons of fuel were recovered from the right fuel tank; the left fuel tank was empty. It is unknown how much fuel, if any, leaked out while the airplane was inverted. According to the Cessna Pilot Operating Handbook for the Cessna 172P, the fuel tanks have a total capacity of 43 gallons, with 3 gallons unusable. Cruise performance, if properly leaned, indicates fuel consumption between 6.4 and 7.3 gallons per hour.
Post-Accident Inspection
The airframe, engine, and related systems were examined under the auspices of an FAA inspector. An engine test run was conducted; the engine started without hesitation and ran at various power settings. The FAA inspector reported no mechanical anomalies with the airframe, engine, or related systems that would have precluded normal operations.