Airworthiness Directive · Amendment 39-17721 · Fuselage
The Boeing Company Airplanes
This AD applies to all The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes, certificated in any category.
We are superseding Airworthiness Directive (AD) 2009-14-02 for certain The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747- 200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes. AD 2009-14-02 required repetitive inspections for wear damage and cracks of the fuselage skin in the interface area of the vertical stabilizer seal and fuselage skin, a detailed inspection for wear damage and cracks of the surface of any skin repair doubler in the area, and corrective actions if necessary. For airplanes on which the fuselage skin has been blended to remove wear damage, AD 2009-14-02 also required repetitive external detailed inspections or high frequency eddy current inspections for cracks of the blended area of the fuselage skin, and corrective actions if necessary. This new AD reduces the repetitive inspection interval, changes certain corrective actions, and expands the applicability. This AD was prompted by a report of wear through the fuselage skin that occurred sooner than the previous repetitive inspection interval. We are issuing this AD to detect and correct wear damage and cracks of the fuselage skin in the interface area of the vertical stabilizer seal and fuselage skin in sections 46 and 48, which could cause in-flight depressurization of the airplane.
At the applicable compliance time specified in paragraph 1.E., ”Compliance,” of Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011, except as specified in paragraph (j)(1) of this AD: Do a detailed inspection of the fuselage skin and any skin repair doubler surface for wear damage and cracking at the vertical stabilizer seal interface, apply Boeing Material Specifications (BMS) 10-86 Teflon-filled coating, and do all applicable corrective actions, except as specified in paragraph (j)(2) of this AD, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011. Do all applicable corrective actions at the applicable compliance time specified in paragraph 1.E., ”Compliance,” of Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011. Repeat the detailed inspection thereafter at intervals not to exceed the applicable repetitive interval specified in paragraph 1.E., ”Compliance,” of Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011, except as specified in paragraph (j)(2) of this AD. The effective date of AD 2009-14-02, Amendment 39-15951 (74 FR 30919, June 29, 2009), is August 3, 2009. Doing the installation of the rub strips in accordance with Boeing Service Bulletin 747-53-2721, Revision 2, dated March 17, 2011, is a terminating action for the work given in Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011, at the locations of the rub strip installation only.
For airplanes on which the skin is blended forward of station 2360 without external reinforcement: At the applicable compliance time specified in Table 4 in paragraph 1.E., ”Compliance,” of Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011, do an external surface HFEC inspection of the blended area of the fuselage skin and the surface of any repair doubler for cracks, apply BMS 10-86 Teflon-filled coating, and do all applicable corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011. Do all applicable corrective actions at the applicable compliance time specified in paragraph 1.E., ”Compliance,” of Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011. Repeat the HFEC inspection thereafter at intervals not to exceed the compliance time specified in paragraph 1.E., ”Compliance,” of Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011. The effective date of AD 2009-14-02, Amendment 39-15951 (74 FR 30919, June 29, 2009) is August 3, 2009. Doing the installation of the rub strips in accordance with Boeing Service Bulletin 747-53-2721, Revision 2, dated March 17, 2011, is a terminating action for the work given in Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011, at the locations of the rub strip installation only.
Installation of corrosion resistant steel (CRES) rub strips in accordance with Boeing Service Bulletin 747-53-2721, Revision 3, dated June 25, 2013, except as specified in paragraph (j)(3) of this AD, is terminating action for the inspections specified in paragraphs (g) and (h) of this AD at the locations of the CRES rub strip installations only.
(1) Where Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011, specifies a compliance time after the “Revision 3 date of this service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD.
(2) Part 3 of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011, is not a requirement of this AD.
(3) Where Boeing Service Bulletin 747-53-2721, Revision 3, dated June 25, 2013, and Boeing Alert Service Bulletin 747-53A2478, Revision 3, dated October 17, 2011, specify to contact Boeing for a modification or for instructions: Before further flight, contact the FAA for instructions using a method approved in accordance with the procedures specified in paragraph (l) of this AD, and accomplish those instructions.
