76-26-04 SCOTTISH AVIATION LIMITED: Amendment 39-2793. Applies to Model HP- 137 Mk. 1 Jetstream airplanes, certificated in all categories, except those airplanes which incorporate Scottish Aviation Limited Modification No. 5111.
Compliance is required as indicated.
To detect cracks in the outer end of each outer wing flap and to prevent possible flap separation from the airplane and possible loss of airplane control, accomplish the following:
(a) For airplanes with 500 or more total landings on the effective date of this AD:
(1) Comply with paragraph (c) of this AD, before further flight, (except that the airplane may be flown in accordance with FAR Sections 21.197 and 21.199 to a base where the work can be performed, provided that the flaps remain in the fully retracted position for the duration of the flight,) unless already accomplished within the last 50 landings and thereafter continue to comply with paragraph (c) of this AD at intervals not to exceed 50 landings.
(2) Comply with paragraph (d) of this AD, within the next 50 landings and thereafter continue to comply with paragraph (d) at intervals not to exceed 500 landings.
(b) For airplanes with less than 500 total landings on the effective date of this AD:
(1) Comply with paragraph (c) of this AD before the accumulation of 500 landings and thereafter continue to comply with paragraph (c) at intervals not to exceed 50 landings.
(2) Comply with paragraph (d) of this AD before the accumulation of 500 landings or within the next 50 landings after the effective date of this AD whichever occurs later, and thereafter continue to comply with paragraph (d) at intervals not to exceed 500 landings.
(c) Visually inspect the outer end of each outer wing flap, Part No. 13760B-405 (left) and 13760B-406 (right), for cracks along the lower flange of the end rib and rib doubler using a magnifying glass with at least 5 power in accordance with the instructions contained in Paragraph 3, Part B of Scottish Aviation Limited Service Bulletin No. 9/5, issue 2, dated August 4, 1976, or an FAA-approved equivalent.
(d) Inspect the outer end of each outer wing flap, Part No. 13760-B-405 (left) and 13760B-406 (right), for cracks along the lower flange of the end rib and rib doubler using the radiographic technique in accordance with the instructions contained in Paragraph 3, Part C of Scottish Aviation Limited Service Bulletin No. 9/5, issue 2, dated August 4, 1976, or an FAA- approved equivalent.
(e) If, during the inspections required by paragraph (c) and (d) of this AD, cracks are found, replace the affected part with a serviceable part of the same part number.
NOTE: A "serviceable part" is defined in Note 1, Parts (a) and (b) of Scottish Aviation Limited Service Bulletin, No. 9/5, issue 2, dated August 4, 1976.
(f) Compliance with paragraphs (a)(1), (a)(2), (b)(1), and (b)(2) may be discontinued upon the incorporation of Scottish Aviation Limited Modification 5111.
This amendment supersedes Amendment 39-2465, (40FR 58129), AD 75-26-16.
This amendment becomes effective January 6, 1977.