Airworthiness Directive · Amendment 39-21689 · Fuselage
The Boeing Company Airplanes
This AD applies to all The Boeing Company Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, -400, -400D, -400F, 747SR, and 747SP airplanes, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 747-100, -100B, -100B SUD, -200B, -200C, - 200F, -300, -400, -400D, -400F, 747SR, and 747SP airplanes. This AD was prompted by reports of cracks found in the front spar shear tie and at the intercostal lug fitting at certain locations. This AD requires repetitive detailed and surface high frequency eddy current (HFEC) inspections of the front spar shear tie and intercostal lug fitting at certain locations for any cracking, and applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products.
Except as specified by paragraph (h) of this AD: At the applicable times specified in the “Compliance” paragraph of Boeing Alert Requirements Bulletin 747-53A2904 RB, dated December 16, 2020, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 747-53A2904 RB, dated December 16, 2020.
Note 1 to paragraph (g): Guidance for accomplishing the actions required by this AD can be found in Boeing Alert Service Bulletin 747-53A2904, dated December 16, 2020, which is referred to in Boeing Alert Requirements Bulletin 747-53A2904 RB, dated December 16, 2020.
(1) Where Boeing Alert Requirements Bulletin 747-53A2904 RB, dated December 16, 2020, uses the phrase “the original issue date of Requirements Bulletin 747-53A2904 RB,” this AD requires using “the effective date of this AD.”
(2) Where Boeing Alert Requirements Bulletin 747-53A2904 RB, dated December 16, 2020, specifies contacting Boeing for repair instructions: This AD requires doing the repair using a method approved in accordance with the procedures specified in paragraph (i) of this AD.
