What happened
On 15 July 2021, a Piper PA-28-140 Cherokee, registration ZS-LRO, departed Virginia Aerodrome for Kruger Mpumalanga International Airport. The aircraft was carrying two pilots and two passengers. While cruising at approximately 1,000 feet above ground level, the engine began running roughly and experienced a drop in RPM.
The pilot monitoring took control of the aircraft and attempted to divert to King Shaka International Airport. However, the engine continued to lose power, making it impossible to maintain the necessary airspeed. As the aircraft lost altitude rapidly, the crew identified a dirt road on a private farm as a potential landing site. The crew successfully landed the aircraft on the road, resulting in zero fatalities and zero injuries, with no damage sustained by the aircraft.
The investigation
Investigators examined the engine's right-side magneto following the incident. The inspection revealed that 11 teeth on the nylon distributor gear had been stripped, with fragments of the teeth found inside the magneto housing. The magneto was subsequently repaired with a new gear and tested successfully.
While various factors can cause nylon distributor gear failure—including aging, fatigue, high temperatures, or mechanical shock—the investigation found no evidence of propeller strikes, lightning, or improper installation in the aircraft's records. The magneto had only operated for 114.33 hours since its last overhaul.