Sport Parachute Main Packing  Techniques When we talk about “square” parachutes, what we really  mean is rectangular plan form, semi-elliptical, or elliptical  plan form.  [Figures 4-1  through  4-3]  Plan form refers to the  shape of the canopy from a “birds eye view.”  There are essentially two ways to pack a square parachute:  flat packing or proper ram-air orientation (PRO) packing.  When flat packing, the canopy is laid on its side so that you  are viewing it in profile. The canopy is S-folded stacking the  line groups on top of one another. Variations to this method  include rolling the nose from the leading edge to the A line,  toward the tail, or splitting the nose cells in half, rolling them  inward, and tucking them into the center cell. The tail is then  split and cocooned around the rest of the canopy. The most common method of packing “square” mains and  reserves, however, is PRO packing. Developed by John  Sherman in the early 1970s when “squares” were first being  introduced, the premise was to pack them the same way one  would pack a round parachute—that is, to separate the four  line groups and flake the perimeter of the parachute with  the nose facing forward and the tail of the canopy facing  rearward. If one were tall enough to raise the round parachute  off the floor, it could be PRO packed. The advantage of  PRO packing is that it results in a more even distribution  of forces during opening shock and on-heading openings.  Figures 4-4  through  4-35 illustrate PRO packing. There  are several variations to this technique designed for special  purposes. Free fall cameramen may require a slower opening  to reduce the opening shock. Canopy Relative Work (CRW)  parachutists may want faster sub-terminal openings. The  rigger should be able to provide guidance to the parachutist  for the type of opening required. Figure 4-3.  Elliptical plan form canopy. Figure 4-2.  Tapered tip plan form canopy. 4-2 Figure 4-4.  Check line continuity and separate line groups. Cock  the slider. Figure 4-1.  Rectangular plan form canopy.