Incident Overview
On 3 October 2021 at approximately 0530Z, a Grumman American AA-5 Traveler, registration ZS-SWX, departed Eagles Creek Airport in Gauteng Province on a private flight with the intention to return to the same airport. The flight was conducted under visual meteorological conditions in accordance with Part 91 of the Civil Aviation Regulations. On board were a pilot and a passenger.
After about 30 minutes of flight at 6,000 feet above ground level, while overhead Buffelspoort Dam, the engine cowling detached from the nose section and fell to the ground. The pilot flew the aircraft back to Eagles Creek Airport and landed without further incident. Both occupants reported no injuries, and the only damage to the aircraft was the lost engine cowling. The operator later retrieved the cowling from the ground near Buffelspoort Dam.
Pilot and Aircraft Information
The pilot held a Private Pilot Licence initially issued on 7 April 2005, with a revalidation issued on 13 July 2021, valid until 31 July 2022. The pilot also held a Class 2 medical certificate issued on 6 July 2021 with a restriction to wear corrective lenses. The pilot had accumulated 736.8 total flying hours, with 7.6 hours on type.
The aircraft, serial number AA5-0040, had a total of 3,201.2 airframe hours. Its maintenance records were up to date, and the aircraft had undergone a mandatory periodic inspection on 8 October 2020 at 3,148.5 airframe hours. The operator complied with all applicable airworthiness directives and service bulletins.
Findings
During the pre-flight inspection, the pilot reported checking the engine cowling and finding it properly latched and secured. After the incident, the pilot noted that the port side bottom latch clip was bent, but it could not be determined whether this occurred before or during the flight. The cowling latch brackets on the lower cowling were found bent, indicating that the latches were fastened when the top cowling separated. Part of a hinge bracket had sheared but remained attached to the engine firewall bracket and nose cowl; the retaining screws did not shear. After the cowling was recovered, the latches were inspected and found serviceable. The aircraft maintenance organisation replaced the engine cowling and latches.
The pilot stated that the port side cowl would not normally become unlatched after being secured, as the pre-flight inspection could be performed from the starboard side. The pilot suggested that the port side latches may have weakened over time, and that during flight, airflow may have raised the cowling from the starboard side, leading to detachment. The pilot also acknowledged that during pre-flight inspection, the security of the port side latches may have been overlooked.
Probable Cause
The engine cowling separated in-flight due to the starboard side engine cowl latches that were not properly secured.