Airworthiness Directive · Amendment 39-14217 · Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SP, and 747SR Series Airplanes; Equipped With Pratt & Whitney Model JT9D-3 and -7 Series Engines
Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SP, and 747SR Series Airplanes; Equipped With Pratt & Whitney Model JT9D-3 and -7 Series Engines
This AD applies to Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747SP, and 747SR series airplanes; certificated in any category; equipped with Pratt & Whitney Model JT9D-3 and -7 series engines; as identified in Boeing Alert Service Bulletin 747-54A2212, dated May 1, 2003.
The FAA is adopting a new airworthiness directive (AD) for certain Boeing transport category airplanes listed above. This AD requires repetitive inspections for cracks of the upper surface of the aft lower spar web of the inboard and outboard struts, as applicable; and repetitive inspections for cracks of the upper surface of the intermediate web bay of the aft lower spar. This AD also requires repetitive inspections and torque checks of the bolts common to the aft lower spar chords and the fitting of the rear engine mount bulkhead for missing, loose, or fractured bolts, as applicable; and corrective action, if necessary. This AD is prompted by reports of cracking in the aft lower spar web and reports of missing and fractured bolts. We are issuing this AD to detect and correct cracking of the aft lower spar web, and to prevent missing, loose, or fractured bolts common to the aft lower spar chords and the fitting of the rear engine mount bulkhead, which could result in the loss of the aft lower spar load path and reduced structural capability of the pylon, which may result in the separation of the 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.
The term “service bulletin,” as used in this AD, means Boeing Alert Service Bulletin 747-54A2212, dated May 1, 2003.
At the applicable times specified in paragraph (g)(1), (g)(2), or (g)(3) of Table 1 of this AD, do initial and repetitive detailed inspections for cracks of the upper surface of the aft lower spar web of the inboard and outboard struts, as applicable; and before further flight, do any applicable repair; by doing all the actions specified in “Part 1—Web Inspection” of the Work Instructions of the service bulletin. For certain airplanes, the repetitive inspections may be deferred or ended provided that the optional stiffener addition specified in paragraph (k) of this AD is done.
Note 1: For the purposes of this AD, a detailed inspection is “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required.”
| For airplanes identified in the Service Bulletin as— | Initial compliance time is— | Repetitive interval is— |
|---|---|---|
| (1) Group 1 airplanes on which the modification specified in Boeing Service Bulletin 747-54-2028, dated August 1, 1972, has been done; and Group 2 airplanes | Within 12 months after the effective date of this AD | At intervals not to exceed 2,400 flight cycles. |
| (2) Group 1 airplanes on which the modification specified in Boeing Service Bulletin 747-54-2028, dated August 1, 1972, has not been done; and Group 7 airplanes | Within 6 months after the effective date of this AD | At intervals not to exceed 350 flight cycles. |
| (3) Group 3, 4, 5, 6, and 8 airplanes | Within 12 months after the effective date of this AD | At intervals not to exceed 1,200 flight cycles. |
At the applicable times specified in paragraph (h)(1) or (h)(2) of Table 2 of this AD, do initial and repetitive detailed inspections for cracks of the upper surface of the intermediate web bay of the aft lower spar; and before further flight do any applicable repair; by doing all the actions specified in “Part 2—Intermediate Web Bay Inspection” of the Work Instructions of the service bulletin. The repetitive inspections may be ended provided that the optional intermediate stiffener addition specified in paragraph (l) of this AD is done.
| For airplanes identified in the Service Bulletin as— | Initial compliance time is— | Repetitive interval is— |
|---|---|---|
| (1) Group 1 through 4 airplanes on which the modification specified in Boeing Service Bulletin 747-71-2188, dated March 14, 1983, has been done and on which the additional work specified in Boeing Service Bulletin 747-71-2188, Revision 1, dated January 17, 1986; or Revision 2, dated March 26, 1987; has not been done | Within 6 months after the effective date of this AD | At intervals not to exceed 350 flight cycles. |
| (2) Group 5 airplanes on which the modification specified in Boeing Service Bulletin 747-54-2115, dated February 14, 1986; or Revision 1, dated May 12, 1988; has not been done | Within 6 months after the effective date of this AD | At intervals not to exceed 350 flight cycles. |
(i) For Group 1 through 6 airplanes identified in the service bulletin: Within 12 months after the effective date of this AD, do a detailed inspection and torque check of the bolts common to the aft lower spar chords and the fitting of the rear engine mount bulkhead for missing, loose, or fractured bolts, and do any applicable replacement (including related investigative actions and corrective action), by doing all the actions specified in “Part 3—Maraging or H-11 Steel Bolt Inspection” of the Work Instructions of the service bulletin, except as provided by paragraph (o) of this AD. Do any applicable replacements (including related investigative actions and corrective action) before further flight, except as provided by paragraph (j) of this AD. Repeat the actions thereafter at intervals not to exceed 18 months. The inspections and torque checks specified in paragraph (i) of this AD may be ended provided that the replacement specified in paragraph (n) of this AD is done.
(j) If during any inspection required by paragraph (i) of this AD, one of the conditions specified in paragraphs (j)(1) and (j)(2) of this AD is found, do the applicable actions specified in paragraphs (j)(1) and (j)(2) of this AD.
(1) If a missing or fractured bolt is found on the inboard strut in any one bay, within 36 months after replacing the bolt with a new bolt, do the replacement specified in paragraph (n) of this AD.
(2) If two or more missing or fractured bolts are found in any one bay, before further flight, do the replacement specified in paragraph (n) of this AD.
Except as provided by paragraph (o) of this AD, accomplishing the optional stiffener addition for the inboard and outboard struts, doing the related investigation actions, and doing any applicable repair, by doing all the actions specified in “Part 4—Stiffener Addition” of the Work Instructions of the service bulletin before further flight after accomplishing the actions specified in paragraph (g) of this AD, defers or ends the repetitive inspections required by paragraph (g) of this AD as follows:
(1) For airplanes listed in paragraph (g)(2) of Table 1 of this AD, accomplishing the optional stiffener addition extends the repetitive inspections required by paragraph (g) of this AD to intervals not to exceed 2,400 flight cycles.
(2) For airplanes listed in paragraph (g)(3) of Table 1 of this AD, accomplishing the optional stiffener addition ends the repetitive inspections required by paragraph (g) of this AD.
For airplanes identified in paragraphs (h)(1) and (h)(2) of Table 2 of this AD: Accomplishing the optional intermediate stiffener addition for the inboard and outboard struts, by doing all the actions specified in “Part 5—Intermediate Stiffener Addition” of the Work Instructions of the service bulletin before further flight after accomplishing the actions specified in paragraph (h) of this AD, except as provided by paragraph (m) of this AD, ends the repetitive inspections required by paragraph (h) of this AD.
(m) Where the service bulletin specifies to install stiffeners as shown in “service bulletin 747-71-2188 Revision 1 or later releases (Group 1, 2, 3, and 4 Airplanes) or 747-54-2115 Original Issue or Revision 1 (Group 5 Airplanes),” this AD requires that those actions be done in accordance with Boeing Service Bulletin 747-71-2188, Revision 1, dated January 17, 1986, or Revision 2, dated March 26, 1987; or Boeing Service Bulletin 747-54-2115, dated February 14, 1986, or Revision 1, dated May 12, 1988; as applicable, except as provided by paragraph (o) of this AD.
For Group 1 through 6 airplanes identified in the service bulletin: Except as provided by paragraph (o) of this AD, replacing all Maraging or H-11 steel bolts with new inconel bolts, doing the related investigation actions, and doing any applicable corrective action, by doing all the actions specified in “Part 6—Maraging or H-11 Steel Bolt Replacement” of the Work Instructions of the service bulletin ends the inspections and torque checks required by paragraph (i) of this AD.
If during any action required by this AD the service bulletin specifies to contact Boeing for additional instructions; or if Boeing Service Bulletin 747-71-2188, Revision 1, dated January 17, 1986, or Revision 2, dated March 26, 1987; or Boeing Service Bulletin 747-54-2115, dated February 14, 1986, or Revision 1, dated May 12, 1988; specifies to repair according to operators equivalent procedures: Before further flight, repair according to a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or according to data meeting the certification basis of the airplane approved by an Authorized Representative for the Boeing Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the approval must specifically reference this AD.
As of the effective date of this AD, no person may install a Maraging or H-11 steel bolt in the locations specified in this AD, on any airplane.
