83-05-05 BRITISH AEROSPACE: Amendment 39-4578. Applies to BAC 1-11 200 and 400 series airplanes, certificated in all categories. Compliance is required as indicated, unless already accomplished. To detect cracking of the windshield glazing frame and prevent possible failure of the adjacent fuselage frame, accomplish the following:
A. For airplanes that have accumulated less than 25,000 total landings on the effective date of this AD, comply with the following:
1. Prior to the accumulation of 15,000 landings or within the next 500 landings after the effective date of this AD, whichever occurs later, unless accomplished within the previous 2,000 landings, visually inspect the windshield glazing frame for cracks internally and externally in accordance with the instructions contained in paragraph 4 entitled "Guidance to Operators" of British Aerospace Alert Service Bulletin 53-A-PM5425, Issue 3, dated February 20, 1978 (hereinafter referred to as the service bulletin).2. Repeat the inspection specified in paragraph A.1. of this AD at intervals not to exceed 2,500 landings from the last inspection until 25,000 landings are accumulated and thereafter comply with the inspection interval specified in paragraph B. of this AD.
B. For airplanes that have accumulated 25,000 landings or more on the effective date of this AD, inspect the area in accordance with paragraph 4 entitled "Guidance to Operators" of the service bulletin within the next 400 landings after the effective date of this AD, unless accomplished within the last 800 landings, and thereafter continue to inspect the area at intervals not to exceed 1,200 landings from the last inspection.
C. If cracks are found during any inspection required by this AD that do not extend forward of the cutouts for the windshield wiper shafts, accomplish the repair modification specified in BAC Modification PM2857, Part (a).
1. Within the next 750 landings after discovery of the cracks onairplanes with less than 25,000 landings at the time of the inspection.
2. Within the next 250 landings after discovery of the cracks on airplanes with 25,000 or more landings at the time of the inspection.
D. If cracks are found during any inspection required by this AD that extend forward of the cutouts for the windshield wiper shafts (refer to Figure 1 of the service bulletin), accomplish the repair modification specified in BAC Modification PM2857, part (a), prior to further flight.
E. Incorporation of BAC Modification PM2857, Part (a), or PM3346 or PM5525 eliminates the repetitive inspection requirement of this AD and constitutes terminating action.
F. Alternate means of compliance which provide an equivalent level of safety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.
G. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and/or modifications required by this AD.
H. For the purpose of complying with this AD, subject to acceptance by the assigned FAA Maintenance Inspector, the number of landings may be determined by dividing each airplane's time in service by the operator's fleet average from takeoff to landing for the airplane type.
The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1).
This amendment becomes effective April 4, 1983.