18. Grasp canopy fabric near line 1D attaching loop. Moving to center line of canopy, pull line 1D and the  control line on the right riser and compare lengths to ensure control line is 15-inches (+ 1-inch) longer  than line 1D.  0006 00  TM 10-1670-287-23&P  0006 00-22  Change 1  Pull both lines evenly before looking at ruler to ensure an accurate  measurement can be obtained. Adjust knot at the toggle to obtain  correct length . NOTE 15 ±  1-IN.  Line 1D  Control Line