Cessna 172 Maintenance Manual page 141

1. General
A. This section applies to the procedures required to perform a wing twist check and is applicable to both
wing. If damage has occurred to a wing, it is advisable to check the wing twist (washout).
B. Wing twist (washout) for the Model 172, 182/T182 and 206/T206 airplanes is 3°37'.
2. Tools, Equipment and Materials
A. The following equipment is required to accomplish the wing twist check procedure:
NAME
32 Inch Straightedge
Protractor Head with
Bubble Level
Bolts Machined to
Specific Lengths
3. Model 172 Series Wing Twist Check Procedure
A. Mark Wing Station Reference Points (Refer to Figure 601)
(1) Locate WS 39.00. Make a mark, with a felt tip pen, approximately 0.50 inch aft of lateral row of
rivets in wing leading edge spar flange.
(2) Locate WS 100.50. Make a mark, with a felt tip pen, approximately 0.50 inch aft of lateral row
of rivets in wing leading edge spar flange.
(3) Locate outboard WS 207.00. Make a mark, with a felt tip pen, approximately 0.50 inch aft of
lateral row of rivets in wing leading edge spar flange.
B. Measure Wing Twist at Each Wing Station (Refer to Figure 601)
NOTE: While performing the following procedure, stay as far away as possible from the "canned"
areas of the wing.
(1) At WS 39.00:
(a) Grind bolt "A" to a dimension of 2.00 inches. Grind bolt "B" to a dimension of 1.00 inch.
Place these bolts 29.50 inches from each other on the upper edge of the straightedge and
secure using tape.
(b) Secure protractor to bottom of the straightedge.
(c) Hold straightedge parallel to wing station and place bolt "A" on mark.
(d) Set bubble in protractor to center, and lock protractor to hold this reading.
(2) At WS 100.50:
(a) Hold straightedge parallel to wing station.
(b) Place bolt "A" on mark, set protractor head against lower edge of straightedge and verify
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 0.45 inch.
Place this bolt 24.00 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).
NOTE:
CESSNA AIRCRAFT COMPANY
SINGLE ENGINE
STRUCTURAL REPAIR MANUAL
MEASURING WING TWIST - INSPECTION/CHECK
NUMBER
Commercially Available
Commercially Available
Fabricate Locally
Forward or aft bolt may be lowered from wing 0.10 inch (maximum) to attain
level indication.
© Cessna Aircraft Company
MANUFACTURER USE
Used to aid in determining
wing twist.
To ensure wings are level.
Used to determine wing
twist.
57-22-00
Page 601
Jun 1/2005