What happened
During a mission involving a Remotely Piloted Aircraft (RPA), the aircraft lost its data-link signal with the ground control station (GCS). Following this loss of communication, the RPA initiated an automated procedure to track toward its programmed home position. However, the aircraft traveled approximately 1,200 km north of its intended starting point, eventually entering the Coral Sea Islands region, where it could no longer be recovered.
The investigation
The investigation focused on the configuration of the ground control station at the time the mission parameters were established. Although the pilot had performed all necessary pre-flight checks and preparations, the investigation identified a critical error in the georeferencing of the map image used by the GCS. Specifically, the south-eastern georeference marker was assigned to a northern hemisphere latitude rather than a southern hemisphere latitude.
This error meant that the mission's home position and all subsequent waypoints were geographically incorrect. While the aircraft was operating in manual mode and did not attempt to follow the erroneous intermediate waypoints during the mission, the loss of signal forced the RPA to rely on the programmed home coordinates, which were located far north of the actual operational area.
Findings
- The primary cause of the loss was the incorrect hemisphere assignment for the south-eastern georeference marker on the GCS map.
- This configuration error placed the programmed home position at a latitude of 17.22° S.
- The loss of the data-link signal triggered the automated return-to-home function, directing the RPA toward the erroneous coordinates.
- The error in the home position would have resulted in the same loss of the aircraft even if the data-link signal had remained continuous and a manual return-to-home command had been issued.