New requirements from the latest edition of CAP 437 8th edition and Helideck Certification Agency (HCA), states that all systems shall be equipped with a breakaway/weak link on the grounding cable. Breakaway devices are already in use on systems with a single core grounding cable, but shall now also be installed on all systems equipped with a grounding indicator. Reference is made to CAP 437, chapter 7, section 3.6.1(b).
The main purpose of the breakaway device is to ensure that the cable releases if the helicopter has to leave unexpectedly, or if someone has forgotten to disconnect the clip prior to takeoff. In these cases it is of great importance that the cable will break away a short distance from the clip. There have previously been cases where the entire length of grounding cable (30 meters) has still been attached to the helicopter at takeoff, causing dangerous situations.