RSM traces an activated unregistered personal locator beacon
Recently, the Rescue Coordination Centre (RCC) asked RSM for help locating an unregistered Personal Locator Beacon (PLB)*. The PLB was successfully located due to the capability of the RSM compliance team.
The beacon was thought to be obscured from the sky, as satellite passes were occurring without detection. The RCC gave the PLB fix a tolerance of +/- 6 nautical miles (10.8 kilometres). Aircraft were not hearing the homing signal on 121.5 MHz (that the PLB also transmits on) – despite being close to an airport.
Approximately 2km from where the PLB was located RSM received the 406 MHz transmissions - a 500 milli-second transmission every 50 seconds. RSM’s Automatic Direction Finder was able to give bearings on these transmissions. Around 100m from the PLB, the homing signal was detected. This enabled easier tracking because this signal was essentially on constantly. However, to find the exact location, the PLB still had to be tracked manually.
Due to health and safety concerns about approaching the address to where the PLB was traced, it was retrieved with the assistance of the New Zealand Police.
* PLBs are for distress situations only. Registration of 406 MHz PLB is a legal requirement in New Zealand. A registered 406 MHz PLB helps the RCC to find the owners contact details in the event that the PLB is activated.