Airworthiness Directive · Amendment 39-16168 · Nacelles/pylons
The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP Series Airplanes Equipped With General Electric CF6-45 or -50 Series Engines, or Equipped With Pratt & Whitney JT9D-3 or -7 (Excluding -70) Series Engines
This AD applies to The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes, certificated in any category, equipped with General Electric CF6-45 or -50 series engines, or equipped with Pratt & Whitney JT9D-3 or -7 (excluding -70) series engines, as identified in Boeing Alert Service Bulletin 747-54A2224, Revision 1, dated November 16, 2006.
The FAA is superseding an existing airworthiness directive (AD), which applies to certain Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. That AD currently requires repetitive inspections to detect cracks and fractures of the strut front spar chord assembly (including the forward side) at each strut location, and repair if necessary. This new AD adds a one-time inspection for cracking of the forward side of the front spar chord assembly on the inboard and outboard struts, installation of a cap skin doubler for certain airplanes, and repair if necessary. These actions terminate the repetitive inspections of the forward side of the strut front spar chord assembly; the inspections of the aft side assembly continue as specified in the existing AD. This AD results from a report of a fractured front spar assembly for strut No. 3, which resulted in the loss of the strut upper link load path. We are issuing this AD to detect and correct cracks and fractures of the nacelle strut front spar chord assembly. Fracture of the front spar chord assembly could lead to loss of the strut upper link load path and consequent fracture of the diagonal brace, which could result in in- flight separation of the strut and engine from 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.
Within 90 days after December 27, 2004 (the effective date of AD 2004-25-05, which was superseded by AD 2007-01-15), perform detailed and HFEC inspections to detect any cracks or fractures of the front spar chord assembly for strut numbers 1 through 4 inclusive, in accordance with Boeing Alert Service Bulletin 747-54A2224, dated September 30, 2004; or in accordance with Part 1—Aft Side Inspection of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-54A2224, Revision 1, dated November 16, 2006. As of January 29, 2007 (the effective date of AD 2007-01-15), only Part 1—Aft Side Inspection of the Accomplishment Instructions of Revision 1 of Boeing Alert Service Bulletin 747-54A2224, Revision 1, dated November 16, 2006, may be used.
(h) Accomplishment of the detailed and HFEC inspections in accordance with Boeing 747 Fleet Team Digest 747-FTD-54-04002, dated April 15, 2004, May 4, 2004, June 1, 2004, July 12, 2004, or July 28, 2004; or Boeing Message 1-C6ELC (Service Request ID No.: 218724992), dated April 14, 2004; before December 27, 2004, is considered acceptable for compliance with the requirements of paragraph (g) of this AD.
(i) For airplanes on which no crack or fracture is detected during the inspections required by paragraph (g) of this AD: At the applicable times specified in Table 1—Repetitive Intervals of this AD, repeat the detailed and HFEC inspections required by paragraph (g) of this AD.
| For airplanes identified in Boeing Alert Service Bulletin 747-54A2224, dated September 30, 2004; or Revision 1, dated November 16, 2006; as— | Repeat the inspections at intervals not to exceed— |
|---|---|
| Group 1 | 1,000 flight cycles or 18 months, whichever occurs first. |
| Group 2 and Group 3 | 1,200 flight cycles or 18 months, whichever occurs first. |
| Group 4 and Group 6 | 1,500 flight cycles or 18 months, whichever occurs first. |
| Group 5 | 2,000 flight cycles or 18 months, whichever occurs first. |
If any crack or fracture is found during any inspection required by paragraphs (g) and (i) of this AD, and Boeing Alert Service Bulletin 747-54A2224, dated September 30, 2004; or Revision 1, dated November 16, 2006; specifies contacting Boeing for appropriate action: Before further flight, repair the crack or fracture using a method approved in accordance with the procedures specified in paragraph (q) of this AD.
Within 90 days after January 29, 2007 the effective date of AD 2007-01-15), do detailed and HFEC inspections for any cracks or fracture of the front spar chord assembly for strut numbers 1, 2, 3, and 4, in accordance with Part 2—Forward Side Inspection of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-54A2224, Revision 1, dated November 16, 2006. If no crack or fracture is found, repeat the inspections thereafter at the applicable interval specified in Table 1 of this AD. Doing the inspections required by paragraph (n) of this AD terminates the forward side detailed and HFEC inspection requirements of this paragraph.
If any crack or fracture is found during any inspection required by paragraph (k) of this AD, and Boeing Alert Service Bulletin 747-54A2224, Revision 1, dated November 16, 2006, specifies to contact Boeing for appropriate action: Before further flight, repair the crack or fracture using a method approved in accordance with the procedures specified in paragraph (q) of this AD.
Detailed and HFEC inspections done before January 29, 2007, in accordance with Boeing 747 Fleet Team Digest 747-FTD-54-06002, dated June 29, 2006; or October 16, 2006; are acceptable for compliance with the initial inspection required by paragraph (k) of this AD.
At the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-54A2230, dated October 30, 2008; except that where the service bulletin specifies a compliance time after the date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD: Do an open-hole high frequency eddy current (HFEC) inspection for cracking of the forward side of the front spar chord assembly on the inboard and outboard struts; and, for airplanes on which the cap skin doubler is not installed, install the cap skin doubler; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-54A2230, dated October 30, 2008.
(o) If any crack is found during the inspection required by paragraph (n) of this AD: Before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (q) of this AD.
(p) Doing all applicable actions required by paragraphs (n) and (o) of this AD terminates the repetitive forward side detailed and HFEC inspection requirements of paragraph (k) of this AD. All aft side inspection requirements of this AD remain in effect.
