What happened
On 23 December 2013, a Piper 2-180, registration ZS-ELK, was performing a takeoff from a private grass airstrip on a farm in Secunda, Mpumalanga. The pilot, the sole occupant, intended to conduct a short cross-country flight that would return to the same airstrip. During the takeoff roll, the engine experienced a sudden loss of power.
In response to the power loss, the pilot executed a forced landing in an open field approximately 500 meters from the end of the runway. The aircraft struck the ground at a high speed and a low angle, causing the right main landing gear to detach and the nose gear to collapse. The aircraft skidded on its belly, with the propeller and right wing striking the terrain. While the aircraft sustained substantial damage to the undercarriage, propeller, and wing, the pilot escaped the wreckage without injury.
The investigation
SACAA AIID investigators examined the wreckage and the aircraft's maintenance history. During the recovery of the aircraft by a maintenance organization, a fuel leak was discovered at the fuel selector valve located on the left cockpit wall.
Technical analysis revealed that an elbow connection between the engine feed pipe and the selector valve was improperly installed, with only three threads engaged. Furthermore, investigators found that the maintenance of the aircraft was not in accordance with manufacturer recommendations. Specifically, the 50-hour inspection for the selector valve had not been performed, and several manufacturer Service Bulletins (SBs) regarding the valve had not been addressed. The investigation also noted that the pilot did not have the specific aircraft type endorsed on his license.
Findings
- The primary cause of the engine power loss was fuel starvation caused by air being drawn into the fuel system through a leaking elbow fitting.
- The leak was facilitated by the improper installation of the elbow, which lacked sufficient thread engagement.
- Improper maintenance contributed to the accident, as the aircraft had not been maintained according to manufacturer specifications, including the omission of critical Service Bulletins and periodic valve inspections.
- The fuel leak had been active for an extended period, but was hidden from pre-flight inspections because the leaking fuel was being absorbed by the cockpit insulation blankets.
Safety action
- The investigation recommended that the Regulator implement a system to monitor private aircraft owners and operators to ensure stricter enforcement of compliance with manufacturer safety-related service bulletins and service letter recommendations.