A A 2 1 3 Spar chord Web Fillet seal (typical) Seal heads (typical) Make a laying surface seal refer to SRM 51-20-05 Web 3 0.050 0.070 Gap (typical) 2 1 2D minumum (typical) Damage cutout 0.50R minimum all corners AFT B B Note: Use this repair at the  inboard end of the spar  when the damage is near  the upper or lower chord. Figure 4-189.  Wing spar repair.  If it is permitted by the applicable aircraft maintenance  manual, installation of a flush access door for inspection  purposes sometimes makes it easier to repair the internal  structure as well as damage to the skin in certain areas. This  installation consists of a doubler and a stressed cover plate.  A single row of nut plates is riveted to the doubler, and the  doubler is riveted to the skin with two staggered rows of  rivets.  [Figure 4-199]  The cover plate is then attached to the  doubler with machine screws. 4-108 Inspection Openings