of line inserted into the finger-trap. So, depending on  the amount of line that is needed to be gained for the  trim adjustment, the rigger may be able to adjust each  end of the line to gain the necessary adjustment. Container repairs share some techniques with canopy repairs,  such as single-side patches. Most repairs, however, involve  replacement of panels or flaps, Velcro $^{®}$, grommets, plastic  stiffeners, worn binding tape, and broken hand tackings.  Even more so than canopy repairs, the cosmetic results of the  container repair are most important to the customer and, thus,  the rigger. A shoddy repair to the container is immediately  obvious each time the user puts on the parachute. Even if it is  functional, it has to look good to instill confidence in the user. The following are repairs found in Section 2, Container: 7.  If this needed line can be gained, remove the bar tacks or  zigzag at each end of the line and reattach after adjusting  the length. Before permanently attaching, the rigger  should simply tie the lines in place and check the trim.  If everything is within limits, then re-tie or finger-trap  and re-stitch with bar tacks or zigzag as per the original. 5.  Measure all the A lines first and then proceed to the B,  C, and D line groups. The lines should be measured  under approximately 10 pounds of tension. As the  rigger moves through the lines and changes riser  groups, the end of the tape measure should be moved  to the corresponding connector link and re-clamped. 6.  Measure the control line groups and fill in the boxes. 1.  Compare the measurements to the original line lengths  as in the manual. 2.  Depending on the type of canopy and type of line  used, most canopies tend to have the center A lines  stretch due to the load on opening. The outside lines  that attach to the stabilizers and the control lines tend  to shrink due to the friction generated by the slider  on opening. The key concept to remember is that  the length of the lines is not the critical dimension.  What is most important is the trim differential, which  determines the angle of attack of the canopy. The trim  differential is the difference in the line length between  the A, B, C, and D lines. The most accurate method  of measuring this is to use the A lines as the base  dimension and then measure A-B, A-C, and A-D. This  method takes into consideration the tolerance allowed.  This dimension is what makes the canopy open and  fly correctly. If the overall length of the lines is 2–3  inches longer or shorter, but the trim is correct, there  is probably no appreciable effect on the canopy. With  this in mind, it may be desirable to “shortline” the  canopy during the trim process in order to not have  to replace any main lines. 3.  Because of the fact that the cascaded main lines may  stretch at different rates, the adjustment to be made  to the lines that have stretched (i.e., gotten longer)  needs to be done at the canopy end and not at the  connector link. 4.  Remove the bar tacks or zigzag stitching at the canopy  end of the lines. 5.  Adjust the line length as needed to return to the  original dimensions. Re-tie the knots or finger-trap  as necessary and re-sew as per the original. 6.  For the lines that may have shrunk in length, it may  be possible to gain as much as 2–3 inches of line  adjustment by utilizing the extra line that is finger- trapped into each line attachment point. Depending  on the type of line used on the canopy, the amount of  excess line finger-trapped may vary. Dacron lines can  have as little as 2–3 inches inserted into the finger- trap and hold securely. The smaller and more slippery  Spectra$^{®}$ line is recommended to have at least 6 inches  •  Materials: E thread—color to match; fabric—type  and color to match; nylon tapes—assorted types and  widths, such as Type-3, Type-4, or Type-12 •  Authorized repairmen: FAA Senior or Master  Parachute Rigger  •  Description: Application of a patch repair to container  panels. •  Applicable products: All types of parachute container  systems. •  3-ring release housing replacement •  Bottom of container (BOC) pocket replacement •  Main container side flap replacement •  Container plastic stiffener replacement •  Container Velcro$^{®}$ replacement •  Container grommet replacement •  Container fabric panel repair Container Fabric Panel Repair Inspection Section 2, Container Reassembly •  Check final trim dimensions against original •  Check continuity so there are no twists or crossed lines •  Verify all junctions are either knotted or finger-trapped  and sewn as per the original 7-38