Cessna C172 Fuel Exhaustion Incident at Lanseria International Airport (ZS-STP)

Incident Overview and Flight Details On 21 August 2023, a Cessna C172 with registration ZS-STP was conducting an instrument flight rules (IFR) navigational training flight under Part 141 of the Civil Aviation Regulations. The flight departed from Wonderboom Airport (FAWB) at 0910Z, with an instructor and a student pilot on board. The planned route included a letdown approach at Pilanesberg Airport (FAPN), a route to Lanseria LIV-VOR, and an instrument landing system (ILS) approach for Runway 07 at Lanseria International Airport (FALA), followed by a touch-and-go landing and return to FAWB. ## Sequence of Events After completing the touch-and-go landing at FALA, the aircraft climbed out and began routing back to FAWB. While passing through approximately 6,500 feet above mean sea level, the engine surged twice. The instructor took control of the aircraft and broadcasted a MAYDAY emergency call to Johannesburg Radar. Air traffic control vectored the aircraft to return to FALA and granted priority landing on Runway 25. However, the aircraft landed approximately 300 metres short of Runway 25. Airport Rescue and Fire Fighting personnel responded to the scene, but both crew members were uninjured, and the aircraft sustained no damage. ## Investigation Findings The investigation determined that the aircraft had exhausted all available fuel on board, which caused the engine to surge and stop. The student pilot had calculated a fuel requirement of 24 gallons for a 3-hour endurance, based on a consumption rate of 8 gallons per hour. The aircraft's total usable fuel capacity is 40 gallons. At the time of the engine failure, the aircraft had covered 2.03 hours of flight time since departure from FAWB, indicating that 17 gallons of fuel remained at departure. The student pilot had estimated the previous flight used only 1 hour of fuel based on a visual inspection of the flight folio and did not use a fuel measuring stick to confirm the actual fuel levels. The instructor did not verify the fuel levels prior to the flight. The aircraft's last annual inspection was conducted on 30 June 2023, and its Certificate of Airworthiness was valid at the time of the incident. ## Probable Cause and Contributing Factors The probable cause of the incident was engine failure due to fuel exhaustion, resulting from the failure of both the instructor and the student pilot to verify the fuel on board. Contributing factors included non-compliance with CAR Part 91 flight planning requirements, the student pilot's failure to use a measuring stick to confirm fuel levels, and the instructor's failure to verify the student's fuel measurements. ## Safety Actions Following the incident, the operator issued a “Red Tag” notice on 22 August 2023, reminding pilots and instructors that fuel measuring sticks must be used to measure fuel and that instructors must verify fuel levels before each flight.