77-15-16 HAWKER SIDDELEY AVIATION, LTD: Amendment 39-2987. Applies to Model H.S. 748, Series 2A airplanes, all serial numbers, certificated in all categories.
Compliance is required as indicated, unless already accomplished.
To prevent cracks in the outboard and center elevator hinge ribs and associated structure of the horizontal stabilizer, accomplish the following:
(a) Within the next 100 hours time in service after the effective date of this AD, and thereafter at intervals not to exceed 100 hours time in service from the last inspection, visually inspect the area of the outboard and center elevator hinge ribs in accordance with Part 2A of the section entitled "Accomplishment Instructions" of Hawker Siddeley Aviation, Ltd., Service Bulletin No. 55/11, dated October 15, 1973, or an FAA-approved equivalent.
(b) If, during an inspection required by paragraph (a) of this AD, a crack, loose rivets, or corroded support bearings or pivot pins are found, before further flight, conduct an internal inspection of the area where the affected hinge ribs attach to the stabilizer rear spar in accordance with Part 2B of the section entitled "Accomplishment Instructions" of Hawker Siddeley Aviation, Ltd., Service Bulletin No. 55/11, dated October 15, 1973, or an FAA-approved equivalent, and comply with paragraph (c) of this AD.
(c) If, during an inspection required by paragraph (a) or (b) of this AD, a crack, loose rivets, or corroded support bearings or pivot pins are found, before further flight, replace or repair the affected parts, as appropriate, in accordance with Part 2C of the section entitled "Accomplishment Instructions" of Hawker Siddeley Aviation, Ltd., Service Bulletin No. 55/11, dated October 15, 1973, or an FAA-approved equivalent, and thereafter, continue to comply with paragraphs (a), (b), and (c) of this AD.
(d) Within the next 1000 hours time in service after the effective date of this AD, replace the external gusset plates (top and bottom) at the outboard and center elevator hinge ribs with larger and heavier gusset plates and add inspection holes in accordance with Parts 2A, 2B, 2C, and 2E of the section entitled "Accomplishment Instructions" of Hawker Siddeley Aviation, Ltd., Service Bulletin No. 55/12, dated January 2, 1974, or an FAA-approved equivalent.
(e) Upon incorporation of the alterations required by paragraph (d) of this AD, the repetitive inspections required by this AD may be discontinued.
This amendment becomes effective August 29, 1977.