77-24-02 SHORT BROTHERS AND HARLAND, LTD: Amendment 39-3080. Applies to SC 7 Series 3 airplanes except those modified in accordance with Shorts Modification No. 1658.
Compliance is required as indicated.
To detect cracks and prevent possible failure of the flap mechanism support structure, accomplish the following:
(a) Before the accumulation of 5,000 landings or within 10 hours time in service after the effective date of this AD, whichever occurs later, unless already accomplished, visually inspect the flap mechanism support structure using a 10 power magnifying glass, for cracking and evidence of chafing and inadequate clearances in accordance with Part A, Steps 1 through 3, of Shorts Alert Service Bulletin No. 27-A64, Revision 3, dated September 7, 1977, (service bulletin) or an FAA-approved equivalent.
(1) If cracks are found during any inspections required by this AD, that are within the acceptable limits shown in Figures 1 and 2 of the service bulletin, reinspect the flap mechanism support structure prior to each day's operation in accordance with paragraph (a) of this AD.
(2) If cracks are found during any inspections required by this AD that are unacceptable in accordance with the criteria defined in Figures 1 and 2 of the service bulletin, before further flight, either replace cracked parts with new parts of the same part number, after which the aircraft may continue in service for an additional 2,400 hours time in service at which time the inspection requirements of this AD must again be complied with, or comply with paragraph (b) of this AD.
(3) If no cracks are found during any inspections required by this AD, reinspect the flap mechanism support structure in accordance with paragraph (a) of this AD at intervals not to exceed 50 landings.
(4) If evidence of chafing or less than minimum clearances are found during any inspections required by this AD, rework the area as shown in Figure 3 of the service bulletin or an FAA-approved equivalent, in accordance with the following compliance schedule:
(i) Within 10 landings of the inspection where no cracking of structural members is found.
(ii) Before further flight, if any cracking is found.
(b) Compliance with the provisions of this AD may be terminated upon accomplishment of the modification of the flap mechanism support structure as shown in figure 4 of the service bulletin, or an FAA- approved equivalent.
(c) For the purpose of complying with this AD, where airplane landings have not been recorded, number of landings shall be established by assuming two landings for each flight hour recorded.
This amendment becomes effective November 28, 1977.