Cessna 172 Maintenance Manual page 64

(4) Any control surface that has a crack that progresses past a stop drilled hole shall be repaired or
replaced.
A control surface that has any of the following conditions shall have a repair made as soon as
(5)
practical:
(a) A crack that is longer than 2 inches.
(b) A crack that does not originate from the trailing edge or a trailing edge rivet.
(c) Cracks in more than six trailing edge rivet locations per skin.
(6) Affected control surfaces with corrugated skins and having a stop drilled crack that does not
extend past the stop drilled hole, may remain in service without additional repair.
(7) Refer to Figure 802 as applicable for repair information.
CESSNA AIRCRAFT COMPANY
SINGLE ENGINE
STRUCTURAL REPAIR MANUAL
© Cessna Aircraft Company
51-75-00
Page 808
Jun 1/2005