AD 79-12-06

79-12-06 CESSNA: Amendment 39-3492 as amended by Amendment 39-3757. Applies to Model 500 (Serial Numbers 500-0001 through 500-0349), Models 500 and 501 (Unit Numbers -0350 through -0520) and Models 550 and 551 (Unit Numbers -0002 through -0114) airplanes with 600 or more hours time-in-service, except those which have been modified in accordance with one of the following Cessna Citation Service Bulletins: SB57-10, Revision 1, dated March 28, 1980; SB57-11, Revision 1, dated March 28, 1980; or SB550-57-3, Revision 1, dated March 28, 1980, as applicable.

COMPLIANCE: Required as indicated unless already accomplished.

A) Within the next 100 hours time-in-service after the effective date of this AD and thereafter within each 600 hours time-in-service until the number of landings or time-in-service threshold for dye penetrant inspection in Table I is reached, visually inspect the upper and lower spar cap stems at Wing Station 37.0 in the areas specified in Cessna Citation Service Letter SL 57-2, Revision 2, dated May 1, 1979, or SL 550-57-1, Revision 1, dated May 1, 1979, as applicable for cracks and/or:

B) Upon reaching or if at or beyond the dye penetrant inspection threshold specified in Table I, within 100 hours time-in-service or 100 landings, whichever occurs first, and thereafter within 600 hours time-in-service or 600 landings, whichever occurs first, dye penetrant inspect the upper and lower spar cap stem at Wing Station 37.0 in the areas specified in Cessna Citation Service Letter SL 57-2, Revision 2, dated May 1, 1979, or SL 550-57-1, Revision 1, dated May 1, 1979, as applicable, for cracks.

TABLE I

MODEL

SERIAL/UNITS NOS DYE PENETRANT INSPECTION THRESHOLD (LANDINGS OR TIME-IN-SERVICE-HOURS) 500 S/N 500-0001 thru 500-0349 4300 500 & 501 Unit -0350 thru -0520 1300 550 & 551 Unit -0002 thru -0114 4300

C) If, as a result of any inspection required by Paragraph A) or B) a crack of less than .3 inches in length is found in the upper spar cap stem, reduce the dye penetrant inspection interval on this spar cap to 200 landings or 200 hours time-in-service, whichever occurs first.

D) If, as a result of any inspection required by Paragraph A) or B) a crack of less than .3 inches in length is found in the lower spar cap stem, reduce the dye penetrant inspection interval on this spar cap to 100 landings or 100 hours time-in-service, whichever occurs first.

NOTE: The FAA encourages compliance with the manufacturer's request that all cracks be reported to the Cessna Customer Service Department.

E) If, as a result of any inspection required by Paragraph A), B), C) or D), a crack of .3 inches in length or longer is found in either spar cap, prior to further flight, repair or modify the wing in accordance with instructions obtained from Cessna Aircraft Company, Jet Marketing Division, Customer Service, P.O. Box 7706, Wichita, Kansas 67277.

F) The time-in-service for initial andbetween repetitive inspections required herein may be adjusted up to 10 hours to facilitate accomplishing them concurrent with other scheduled maintenance on the airplane.

G) Aircraft may be flown in accordance with Federal Aviation Regulation 21.197 to a location where this AD can be accomplished.

H) Any equivalent method of compliance with this AD must be approved by the Chief, Engineering and Manufacturing District Office, Federal Aviation Administration, Room 238, Terminal Building No. 2299, Mid-Continent Airport, Wichita, Kansas 67209.

Cessna Citation Service Letters SL57-2, Revision 2, dated May 1, 1979; and SL550-57-1, Revision 1, dated May 1, 1979; and Cessna Citation Service Bulletins SB57-10, Revision 1, dated March 28, 1980; SB57-11, Revision 1, dated March 28, 1980; and SB550-57-3, Revision 1, dated March 28, 1980, cover the subject matter of this AD.

Amendment 39-3492 became effective June 21, 1979.

This Amendment 39-3757 becomes effective April10, 1980.