TM 10-1670-287-23&P  0058 00  DIRECT SUPPORT MAINTENANCE  MC-4 RAM AIR FREE-FALL PERSONNEL PARACHUTE SYSTEM  CANOPY RIB  THIS TASK COVERS:  INITIAL SETUP:  Tools Equipment Condition  Personnel Required  Materials/Parts  REPLACE (WHOLE RIB)  0058 00-1  x Replace  Layout on packing table or other  suitable area.  92R (10) Parachute Rigger Needle, Tacking (Item 29, WP 0063 00)  Sewing Machine, Light-Duty (Table 1, WP 0050 00)  Sewing Machine, Double Needle w/Puller ($^{3}$/$_{8}$ gauge) (Table 1, WP 0050 00)  Shears (Item 39, WP 0063 00)  Stitch Removal Tool (Item 40, WP 0063 00)  Tape Measure (Item 42, WP 0063 00)  Rib, Loaded/Unloaded (WP 0068 00/WP 0069 00) As Applicable  Thread, Nylon, Size E (Item 43/44, WP 0076 00)  1.  Cut stitching to open tail section approximately 12-inches on each side of the damaged rib.  2.  Premark the top and bottom skin and rib where the reinforcement tapes are sewn on the rib and  every 3-inches to be used as guide marks.  3.  Layout the canopy and carefully cut the stitching and remove any items necessary to expose the  damaged rib, such as suspension line attaching loops and reinforcing tapes.  4.  Carefully cut and remove the double rows of stitching securing the rib to the top and bottom skin and  remove the damaged rib.  5.  Obtain a new rib from supply stock.  6.  Using the damaged rib as a pattern, transfer the guide marks made in step 2., above, on to the  replacement rib as required.  7.  Starting at the tail end of the rib, fold and sew the bottom of the rib to the bottom skin with a double  needle sewing machine, using size E nylon thread and 7 to 11 stitches per inch.  RIB REPLACEMENT, BOTTOM SKIN  NOSE SEAM, BOTTOM SKIN  CROSS SEAM, BOTTOM SKIN 