1. Mark for a cutout at the root of the flap for the flap control arm to move through when the flaps have been lowered. Bottom edge of cutout should be approximately even with the top of the hinge. Left side flap shown, right side similar.
2. Cut out area marked in step 1, Round over all sharp corners, particularly the inside corners.
3. Make a doubler from .063” 6061-T6 2 ¼” by 7/8”
4. A strap duplicator is a handy tool to have around.
5. Place pin of the strap duplicator in rivet hole and align edge of doubler with edge of the flap. Bottom of doubler should be flush with the top of the control arm cutout.
6. Drill 2 #40 holes 5/8” from either side of the hole just drilled, same distance from bottom of the hole drilled previously.
7. Position doubler on flap and cleco in place. Transfer drill the 2 #40 holes into the flap, then updrill to #30.
8. Countersink the 3 holes for BSC-43 rivets.
9. Install doubler with 3 BSC-43 rivets.
10. Repeat for the other flap.
