Generally the kill line on your pilot chute is made from spectra. The strength of the line is not so much of an importance as the correct length of it, because if it breaks,all it means is that your pilot chute won’t collapse. Over time, Spectra shrinks due to the heat generated by friction and it is because of this that the problem arises. Often when replaced, the line is made a little longer in order to compensate which off sets the collapsed position of the pilot chute and can cause it to spin up which is why we often see people on the packing mat untwisting their bridle.
When too short, it will reduce the effectiveness of the pilot chute and this, in turn, has many effects on the deployment of your main parachute. These range from a lazy liftoff of the d-bag from the container, which can cause ‘Funky’ openings and line twists, all the way through to pilot chute in tow, which is one of our malfunctions.
As a rule of thumb, your kill line should be replaced or readjusted at approximately 250 jumps. It all depends on where you jump.