What happened
On the morning of 27 April 2025, a flight instructor and a student pilot were conducting a routine training flight departing from Cape Winelands Aerodrome (FAWN) in the Western Cape. The flight, operating under visual meteorological conditions, was part of a Part 1/41 training program. The crew was performing standard circuit exercises in a Piper PA-28-140 Cherokee, registration ZS-FWR.
During the flight, the instructor initiated a simulated engine failure procedure on final approach. This maneuver required reducing engine power to practice emergency protocols before increasing power to recover. However, upon attempting to increase power, the engine failed to respond, began misfiring, and lost significant power. The instructor declared a "PAN-PAN" to air traffic control and attempted to divert back to the aerodrome. When power could not be restored, the crew executed a forced landing in a suitable open area on a nearby farm. There were no injuries to the occupants, and the aircraft sustained no damage during the landing.
The investigation
Following the incident, investigators examined the engine and discovered that the right magneto had failed. This failure directly caused the engine to run rough and lose power. During the inspection, it was also noted that a scat hose, which directs air from the engine cowl to the carburetor intake, had become detached. Investigators determined that this detachment was a secondary effect caused by the engine backfiring during the magneto failure, rather than the primary cause of the power loss.
An approved maintenance organization performed a detailed inspection of the failed component. Their analysis revealed that a broken distributor gear within the magneto was the internal mechanical failure that triggered the malfunction.
Findings
- The primary cause of the engine malfunction was the mechanical failure of the right magneto due to a broken distributor gear.
- The engine misfired and lost power as a direct result of this component failure.
- The detachment of the scat hose was a consequence of engine backfiring and did not initiate the incident.
- Weather conditions were clear and did not contribute to the occurrence.