Accident Overview
On September 27, 2021, at about 2238 eastern daylight time, a Cessna 172G, registration N4118L, was substantially damaged in an accident near Miramar, Florida. The flight instructor and student pilot sustained serious injuries. The airplane was being operated as a Title 14 Code of Federal Regulations Part 91 instructional flight.
Preflight Inspection
The student pilot reported that during the preflight inspection, she noted the airplane had been operated for 1.2 hours since the fuel tanks were filled. She visually inspected both fuel tanks and saw fuel inside but did not have a fuel dipstick available. She informed the flight instructor that the fuel level was a “little less” than full. The flight instructor also performed a preflight inspection but did not check the fuel tanks.
Flight Instructor's Account
The flight instructor stated that she checked the right fuel tank, which she verified by feel as full, but did not check the left fuel tank, nor did she use the fuel dipstick. The student pilot checked the left fuel tank and told her it was full. After proceeding to a nearby airport with the mixture control set to full rich, the student pilot performed 11 stop-and-go landings. They then returned to the departure airport with the mixture control still full rich. The instructor indicated that had she known the left fuel tank was not full, she would have refueled before the return flight.
Loss of Engine Power
About 3 miles from the airport, the engine lost total power. The instructor noted that both fuel gauges were stuck between 1/2 and empty. She moved the fuel selector from the BOTH position, where it had been since engine start, to the LEFT and then the RIGHT tank positions, but engine power did not restore. She informed the student of the impending forced landing to a street.
Forced Landing and Impact
After touchdown on the road, the instructor turned to avoid traffic and the airplane impacted another tree. The instructor was not wearing the shoulder harness, which she said contributed to her injury.
Post-Accident Examination
The airplane came to rest upright with substantial damage to the fuselage and right horizontal stabilizer. Neither fuel tank was breached. The right fuel tank was empty, while about 2.5 gallons of fuel were drained from the left fuel tank. The fuel selector was found between the BOTH and RIGHT fuel tank positions. The airplane’s published total unusable fuel amount was 3.0 gallons (1.5 gallons in each tank). The engine was removed from the airframe, and only “drops” of fuel were noted in the fuel line between the fuel strainer and carburetor. No fuel was found in the airframe fuel strainer. Extensive impact damage precluded operational testing of the fuel quantity indicating system; the fuel transmitters were not tested. No fuel was noted in the carburetor bowl. Based on the hour meter, the airplane had been operated for about 4.5 hours since the fuel tanks had been filled.