What happened
On 14 November 2007, a PA28-140 aircraft, registration ZS-FTH, departed from Brakpan Benoni Aerodrome (FABB) for a dual training flight. The flight, which included an instructor and a student pilot, was intended to be a short circuit returning to the same aerodrome.
During the initial climb-out phase, the aircraft experienced a sudden sink and a significant loss of climb performance. While the pilot attempted to scan the cockpit for mechanical abnormalities, none were identified. In an effort to avoid nearby trees, the pilot opted to maintain a straight flight path to seek a landing site. During this maneuver, the aircraft struck high-tension Eskom power lines running parallel to the N17 highway. The impact caused the aircraft to bank left and crash onto the traffic island of the N17 highway near Carnival City. Both occupants sustained minor injuries.
The investigation
SACAA AIID investigators examined the wreckage and the environmental conditions at the time of the accident. The inspection of the engine and propeller suggested they were operating normally, and no structural failures were found to have occurred prior to the impact. The investigation also reviewed the aircraft's weight and balance, noting that while the aircraft was within its maximum takeoff weight, it was operating only 86 lbs below the limit.
Findings
- The primary cause of the accident was poor aircraft climb performance which prevented the aircraft from clearing obstacles.
- A significant contributing factor was the high density altitude, calculated at approximately 8,300 ft, resulting from a high surface temperature of 29°C.
- The combination of high density altitude and a heavy takeoff weight adversely affected the aircraft's acceleration and ability to climb.
- The aircraft's impact with the power lines caused substantial damage to the airframe, specifically the right wing, undercarriage, and propeller.