77-13-14 HAWKER SIDDELEY AVIATION, LIMITED: Amendment 39-2939. Applies to Model DH-114 airplanes, certificated in all categories, except those modified in accordance with either Hawker Siddeley Modification 1102 or 1103.
Compliance is required as indicated, unless already accomplished.
To detect corrosion and cracking of the drag brace fittings at the center section spar lower cap, and prevent possible structural failure of the wing, accomplish the following:
(a) Within the next 50 hours time-in-service after the effective date of this AD, inspect the drag brace fittings, P/N 4 FS.1797(L.H.) and 4 FS.1798(R.H.), for corrosion and cracks in accordance with paragraph 4, entitled "Inspection of Fittings," of Hawker Siddeley Aviation, Ltd., Technical News Sheet, Series 114, No. F.18, dated April 9, 1973, or an FAA- approved equivalent.
(b) If a crack or evidence of severe corrosion is found in either drag brace fitting during the inspection specified in paragraph (a)of this AD, before further flight, replace the drag brace fitting with an improved fitting, P/N 14FS.6069 (L.H.) or P/N 14FS. 6070 (R.H.), in accordance with the instructions set forth in paragraph 5.2 of Hawker Siddeley Aviation, Ltd., Technical News Sheet, Series 114, No. F.18, dated April 9, 1973, or an FAA-approved equivalent.
(c) "Severe corrosion" as used in this AD is internal corrosion that has progressed to a point where there is evidence of corrosion breaking through the exterior surface of the fitting. "Surface corrosion" as used in this AD means corrosion limited to surface pitting.
NOTE: The Hawker Siddeley Aviation, Ltd., Model DH-114 Maintenance and Repair Manual further defines the terms "severe corrosion" and "surface corrosion."
(d) If, during an inspection specified in paragraph (a) of this AD, no crack is found and evidence of corrosion is found but it is limited to surface corrosion and does not constitute the severe corrosion specified in paragraph (b) of this AD, before further flight, remove the corrosion and protect the surface from further corrosion in accordance with FAR 43.13, and thereafter reinspect the drag brace fittings in accordance with the inspection requirements of paragraph (a) of this AD at intervals not to exceed 100 hours time-in-service from the last inspection.
NOTE: Advisory Circular AC 43.13-1A, "Acceptable Methods, Techniques and Practices - Aircraft Inspection and Repair," contains information relating to corrosion protection and removal.
(e) If, during an inspection specified in paragraph (a) of this AD, no crack is found in the fittings, and the fittings are free of evidence of any corrosion, reinspect the fittings in accordance with the inspection requirements of paragraph (a) of this AD at intervals not to exceed 100 hours time-in-service from the last inspection.
(f) The repetitive inspections required by paragraphs (d) and (e) of this AD may be terminated upon the installation of the improved fittings, P/Ns 14FS. 6069 (L.H.) and 14FS. 6070 (R.H.), in accordance with the instructions set forth in paragraph 5.2 of Hawker Siddeley Aviation, Ltd., Technical News Sheet, Series 114, No. F.18, dated April 9, 1973, or an FAA- approved equivalent.
This amendment becomes effective July 7, 1977.