AD 73-26-09

73-26-09 CESSNA: Amendment 39-1763 as amended by Amendment 39-1983. Applies to Model 500 (Serial Numbers 500-0001 through 500-0183) airplanes, with 400 or more hours' time in service.

Compliance: Required as indicated, unless already accomplished.

To detect cracks in the left and right flight compartment side windows (P/Ns 5511265-3 and -4), within the next 25 hours' time in service after the effective date of this AD, (on all airplanes with 400 or more hours' time in service) and thereafter at intervals not to exceed 200 hours' time in service, except as provided in Paragraph B(2), accomplish the following in accordance with the inspection procedures set forth in Cessna Service Letter SL56-2, dated November 9, 1973, or FAA-approved revisions or any equivalent method approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region:

A) Either by use of x-ray procedures outlined in Cessna Service Letter SL56-2, dated November 9, 1973, inspect the flight compartment side windows (P/Ns 5511265-3 and -4) at the attachment locations, or in the alternative, visually inspect the window attachment locations by first removing the window outside retainers in accordance with the manufacturer's service instructions.

B) (1) Prior to further pressurized flight replace unairworthy windows if as a result of any inspection required by this AD any of the following conditions are found:

(a) A crack is visible in the window pane which has progressed past the edge of the retainer.

(b) Any three or more screw holes are interconnected by a crack.

(c) A crack has progressed to three inches or longer.

(d) The sum of individual crack lengths exceeds six inches.

(2) If a crack is discovered in a window pane but does not exceed any of the conditions specified in Paragraph B(1), inspect the window panes each 100 hours' time in service thereafter per Paragraph A of the AD until the window panes are replaced.

C) Upon accumulation of 400 hours' time in service inspect replacement window panes in accordance with the requirements of this AD.

D) The inspections and 400 hour window replacement requirements of this AD may be discontinued upon installation of left and right flight compartment side windows (P/N 5511285-3 and -4) in accordance with Cessna Service Bulletin SB 56-4 dated July 24, 1974, or later approved revisions. Any equivalent method must be approved by the Chief, Engineering and Manufacturing Branch, FAA, Central Region.

Amendment 39-1763 became effective December 26, 1973.

This Amendment 39-1983 becomes effective October 9, 1974.