Ask a Rigger—How Do I Know If My Brake Lines are the Correct Length?
By Kevin Gibson
Ask A Rigger
Wednesday, June 23, 2021
In a few words, your brake lines, aka control lines, need to be long enough so your canopy flies at full speed and short enough to provide the most eﬀective flare. Lots of things can happen to make brake lines the wrong length. Having it wrong can change the way your canopy performs in turns, how it flares and even how it opens.
Brake lines have three important measurements. The first one, which is sort of set in stone, comes from three or four line attachments on the trailing edge of the canopy to the cascade (where they join into one control line). Although these lengths could change over the life of some types of line, they rarely need addressing.
The second two measurements deserve more attention. One starts from the cascade and ends at the cat’s eye (the built-in loop where you insert the end of the toggle to set the brakes each time you pack). Techs call this the “lower control line.”
The factory sets the length of the lower control line and sews it down. It seldom needs adjustment throughout the life of the lines—typically 450-500 jumps. However, some line types shrink more than others before reline time. In the extreme, that could aﬀect openings enough to call for a new set of lines from the cascades down.
The third important length may need adjusting for a variety of reasons, even out of the box. This one runs from the cat’s eye to the toggle (aka “brake to toggle”).
The factory sends a new canopy with this section either set and sewn down or just marked for the rigger to set and tie oﬀ. On most intermediate-performance canopies, marked-and-rigger-set lines work better than factory-set-and-sewn lines. With rigger-set lines, the rigger and client can more easily collaborate on the ultimate length and tweak it. It’s diﬃcult to adjust the factory-set-and-sewn lines without damaging the line itself. With high-performance canopies, resetting the brakes calls for an expert with factory guidance.
Adjusting for Success
Most importantly, the canopy has to land well. For starters, the overall length after you release the brakes has to allow a little slack so that the tail of the canopy can fly free. However, the jumper also has to be able to pull the toggles down enough to flare into level flight and then extend them to keep flying flat until the canopy reaches its slowest airspeed before stalling. That final speed depends on the canopy design, the jumper’s weight and how well the jumper unloads the canopy while running out the landing. The jumper’s flare and landing technique counts for a lot.
Contrary to what a lot of skydivers may think, the brake lines don’t need to be short enough for the jumper to pull the tail below the nose for reverse flight. Collapsing the canopy like this can be a lot of fun (if done correctly at a safe altitude, of course), but this action has nothing to do with the canopy’s several stall modes. Still, the “stall” label remains from the old days before informed discussions on canopy flight became part of the lexicon. On many—maybe most—canopies on which the brakes are trimmed correctly, the jumper can’t fly backward even with the brakes fully extended to arms’ length.
So, all in all, good trim spans full flight through a well-executed landing with the jumper reaching the canopy’s minimum flight speed while still supporting whatever weight the jumper hasn’t unloaded onto his sneakers.
Front riser maneuvers—also a blast and very useful for maneuvering and building speed for flashy landings—may require a longer brake setting. At an appropriately high altitude for experimentation, with toggles in hand, pull one front riser down. If the canopy bucks, ask your rigger to lengthen the brake-to-toggle measurement. Sometimes that requires replacing everything from the cascade down, depending on the construction of the brake lines. However, add only two inches at a time to make sure it doesn’t compromise the flare. Once you adjust to where the canopy flies smoothly through a front-riser maneuver and lands well, you’re good to go.
Some line types remain dimensionally stable through the life of the lineset. With them, you can fine-tune the length and forget about it. But if you have microline (the thin, bright-white line that is slowly going out of style), your brake setting will change with use. For this reason, manufacturers and riggers shouldn’t really set and sew the microline brake-to-toggle length on a main canopy. With microline, you will need to periodically evaluate and maybe adjust your brake setting.
Unfortunately, microline lower-control lines (above the cat’s eye) will also shrink with use, which will aﬀect openings. But it’s hard to know where to begin with replacing them, since other lines on the canopy are also shrinking inconsistently. Fortunately, most new designs bypass microline for Vectran or HMA, which hold their settings better.
So, if your microline canopy doesn’t fly and land like it used to, or if your needs and desires don’t match the original brake settings that came with your canopy, you can have a rigger take a look. Then on a hop-and-pop with nobody in the way, test all your flight modes thoroughly following small adjustments so you don’t get surprised.
Kevin Gibson | D-6943 and FAA Designated Parachute Rigger Examiner
Rahlmo’s Rigging at Skydive Orange in Virginia