Cessna 172 Maintenance Manual page 145

(2) At WS 100.00:
(a) Hold straightedge parallel to wing station.
Place bolt "A" on mark, set protractor head against lower edge of straightedge and verify
(b)
bubble in protractor head indicates level.
(3) At WS 207.00:
(a) Remove bolt "A" from straightedge. Grind another bolt "A" to a dimension of 0.66 inch.
Place this bolt 20.00 inches from bolt "B" and secure to straightedge.
(b) Hold straightedge parallel to wing station and place bolt "A" on mark.
(c) Check to assure that protractor bubble is still centered. If proper twist is present, the
protractor readings will be the same (parallel).
Forward or aft bolt may be lowered from wing 0.10 inch (maximum) to attain
NOTE:
level indication.
CESSNA AIRCRAFT COMPANY
SINGLE ENGINE
STRUCTURAL REPAIR MANUAL
© Cessna Aircraft Company
57-22-00
Page 605
Jun 1/2005