Airworthiness Directive · Amendment 39-17638 · Fuselage
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 747-100, 747-200B, and 747-200F series airplanes, certificated in any category, as listed in Boeing Alert Service Bulletin 747-53A2371, Revision 2, dated December 11, 2012.
We are superseding Airworthiness Directive (AD) 94-13-06 for certain The Boeing Company Model 747 series airplanes. AD 94-13-06 required repetitive detailed inspections to detect cracking in certain fuselage upper deck tension ties, repair or modification of any cracked tension ties, and repetitive inspections of repaired and modified tension ties and repair or modification if necessary. AD 94-13-06 also provided for optional terminating action for the repetitive detailed inspections of tension ties that had not been repaired or modified. This new AD retains the repetitive inspections, mandates the previously optional terminating modification, and adds, for tension ties that have not been repaired or modified, repetitive inspections that must be done concurrently with the existing repetitive inspections. This AD was prompted by an evaluation by the design approval holder indicating that the upper deck tension ties of the fuselage are subject to widespread fatigue damage. We are issuing this AD to prevent widespread fatigue damage of certain fuselage upper deck tension ties, which could result in reduced structural integrity of the airplane.
Except as required by paragraph (k)(3) of this AD, at the applicable time specified in Tables 1 and 3 of paragraph 1.E., “Compliance” of Boeing Alert Service Bulletin 747-53A2371, Revision 2, dated December 11, 2012: Do detailed and surface high frequency eddy current (HFEC) inspections for cracks in the tension ties, as applicable, and do all applicable corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2371, Revision 2, dated December 11, 2012, except as required by paragraph (k)(2) of this AD. The effective date of AD 94-13-06, Amendment 39-8946 (59 FR 32879, June 27, 1994) is July 27, 1994. Do all applicable corrective actions before further flight. Repeat the detailed and HFEC inspections thereafter at the time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2371, Revision 2, dated December 11, 2012, except as specified in paragraph (k)(1) of this AD. Repair of a tension tie, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2371, Revision 2, dated December 11, 2012, except as required by paragraph (k)(2) of this AD, terminates the requirements of this paragraph for that tension tie only.
Except as provided by paragraph (k)(3) of this AD, at the applicable time specified in Table 3 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2371, Revision 2, dated December 11, 2012: Modify the tension ties, including doing an open-hole HFEC inspection for cracks before enlarging the hole, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2371, Revision 2, dated December 11, 2012. Modification of the tension ties terminates the requirements of paragraph (g) of this AD. If any cracking is found, before further flight, do the repair using a method approved in accordance with the procedures specified in paragraph (l) of this AD.
At the applicable time specified in Table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2371, Revision 2, dated December 11, 2012: Do a detailed inspection of all repaired and modified tension ties, and do all applicable corrective actions, except as required by paragraph (k)(2) of this AD, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2371, Revision 2, dated December 11, 2012, except as required by paragraph (k)(2) of this AD. Repeat the inspection thereafter at the times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2371, Revision 2, dated December 11, 2012. Do all applicable corrective actions before further flight.
