Airworthiness Directive · Amendment 39-16131 · Fuselage
Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747-400, 747SR, and 747SP Series Airplanes
This AD applies to Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747-400, 747SR, and 747SP series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-53A2749, dated September 25, 2008.
The FAA is superseding an existing airworthiness directive (AD), which applies to certain Boeing Model 747 airplanes. The existing AD currently requires repetitive inspections for cracking, and repair as necessary, of lower lobe body frames (sections 42 and 46) of the fuselage. The existing AD also provides for optional modification of the frames, which terminates the repetitive inspections. This new AD requires additional repetitive inspections for cracking of certain fuselage frames, and corrective actions if necessary. This AD results from a new report of a crack found in a body frame with a tapered side guide bracket at fuselage station 1800, located on the left side between stringers 39 and 40; the frame was severed. We are issuing this AD to detect and correct the loss of structural integrity of the fuselage, which could result in rapid depressurization of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
For airplanes listed in Boeing Alert Service Bulletin 747-53A2237, Revision 1, dated March 28, 1986: Perform a detailed visual inspection for frame cracking from fuselage section 540 to 760, and 1820 to 1900, stringers 35 left to 42 left, in accordance with Section III of Boeing Alert Service Bulletin 747-53A2237, Revision 1, dated March 28, 1986. Do the inspection at the time specified in paragraph (g)(1), (g)(2), or (g)(3) of this AD, as applicable. If any crack is found, before further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, or using a method approved in accordance with the procedures specified in paragraph (p) of this AD. Repeat the inspection at intervals not to exceed 3,000 landings until the terminating action specified in paragraph (g)(4) or (k) of this AD is performed.
(1) Within 300 landings for airplanes that have accumulated more than 12,000 landings on September 17, 1986 (the effective date of AD 86-18-01, amendment 39-5390).
(2) Within 800 landings for airplanes that have accumulated 10,000 to 12,000 landings on September 17, 1986.
(3) Within 800 landings or prior to the accumulation of 10,000 landings, whichever occurs later, for airplanes that have accumulated less than 10,000 landings on September 17, 1986.
(4) Modification of the frames before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-53A2237, Revision 1, dated March 28, 1986, constitutes terminating action for the repetitive inspections required by paragraph (g) of this AD.
(h) For airplanes listed in Boeing Alert Service Bulletin 747-53A2259, Revision 1, dated April 18, 1986: Perform a visual inspection of cargo side guide support brackets from fuselage station 1500 to 1800, right and left hand side, for a proper machined taper in accordance with Section III of Boeing Alert Service Bulletin 747-53A2259, Revision 1, dated April 18, 1986. Do the inspection at the time specified in paragraph (h)(1), (h)(2), or (h)(3) of this AD, as applicable. If any cargo side guide support bracket is improperly tapered, before further flight, perform a detailed visual inspection of the frame area adjacent to the untapered bracket for cracking in accordance with Boeing Alert Service Bulletin 747-53A2259, Revision 1, dated April 18, 1986. If any crack is found, before further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, or using a method approved in accordance with the procedures specified in paragraph (p) of this AD. Repeat the detailed visual inspection at intervals not to exceed 3,000 landings until the terminating action specified in paragraph (h)(4) of this AD is performed. Accomplishment of the inspections required by paragraph (k) of this AD terminates the inspections required by this paragraph.
(1) Within 300 landings for airplanes that have accumulated more than 12,000 landings on September 17, 1986 (the effective date of AD 86-18-01, amendment 39-5390).
(2) Within 800 landings for airplanes that have accumulated 10,000 to 12,000 landings on September 17, 1986.
(3) Within 800 landings or prior to the accumulation of 10,000 landings, whichever occurs later, for airplanes that have accumulated less than 10,000 landings on September 17, 1986.
(4) Installation of a tapered strap adjacent to the affected brackets before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-53A2259, Revision 1, dated April 18, 1986, constitutes terminating action for the repetitive inspections required by paragraph (h) of this AD.
(i) For Boeing Model 747SR airplanes only, based on continued mixed operation of cabin pressure differentials, the initial inspection thresholds and reinspection intervals specified in AD 86-18-01 may be multiplied by a 1.2 adjustment factor. This provision is not applicable to paragraphs (k), (m), and (n) of this AD.
(j) For the purposes of complying with AD 86-18-01, the number of landings may be determined to equal the number of pressurization cycles where the cabin pressure differential was greater than 2.0 pounds per square inch. This provision is not applicable to paragraphs (k), (m), and (n) of this AD.
For airplanes identified in Boeing Alert Service Bulletin 747-53A2749, dated September 25, 2008, that have accumulated 22,000 or fewer total flight cycles as of the effective date of this AD: Do initial and repetitive detailed inspections for frame cracking from fuselage body stations 1500 to 1800, stringers 39 to 40, by doing all the actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2749, dated September 25, 2008, except as required by paragraph (l) of this AD. Do the inspections and corrective actions at the times specified in paragraph 1.E. of Boeing Alert Service Bulletin 747-53A2749, dated September 25, 2008, except as required by paragraphs (m) and (n) of this AD. Accomplishment of the inspections required by this paragraph terminates the inspections required by paragraph (h) of this AD.
If any crack is found during any inspection required by this AD, and Boeing Alert Service Bulletin 747-53A2749, dated September 25, 2008, specifies to contact Boeing for appropriate action: Before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (p) of this AD.
(m) Where Boeing Alert Service Bulletin 747-53A2749, dated September 25, 2008, specifies a compliance time after the date of the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.
(n) Where Boeing Alert Service Bulletin 747-53A2749, dated September 25, 2008, specifies a compliance time related to accomplishing an action “as given in Boeing Service Bulletin 747-53A2259,” this AD requires compliance within the specified compliance time after the applicable compliance time required by paragraph (h) of this AD.
Accomplishing the repetitive frame inspections required by AD 2006-05-02, amendment 39-14499; or AD 2005-20-30, amendment 39-14327; terminates the inspections required by paragraphs (g), (h), and (k) of this AD.
