Airworthiness Directive · Amendment 39-11537 · Boeing Model 727 Series Airplanes
Boeing Model 727 Series Airplanes
Model 727 series airplanes, as listed in Boeing Service Bulletin 727-57-0177, dated December 22, 1988; certificated in any category.
Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (g)(1) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 727 series airplanes, that currently requires repetitive inspections of the front spar web between the upper and lower seals of the center section of the wings, and repair, if necessary. That amendment also provides for an optional terminating modification for the repetitive inspections. This amendment requires a new terminating modification for the repetitive inspections. For certain airplanes, this amendment also requires new repetitive inspections to detect discrepancies of the front spar web. This amendment is prompted by a report indicating that the optional terminating modification in the existing AD does not adequately address the identified unsafe condition. The actions specified by this AD are intended to prevent fatigue cracks in the front spar web, which could lead to fuel leakage into the air-conditioning distribution bay and/or depressurization of the cabin, and to prevent fuel fumes in the cabin of the airplane.
To prevent fatigue cracks of the front spar web of the center section of the wings, which could lead to fuel leakage and/or depressurization of the cabin, or to prevent fuel fumes in the cabin of the airplane, accomplish the following:
(a) For areas on which the front spar web between the upper and lower seals of the center section of the wings has not been repaired or modified in accordance with Figure 2 or 3 of Boeing Service Bulletin 727-57-0177, dated December 22, 1988; Revision 1, dated November 21, 1991; or Revision 2, dated September 16, 1993: Prior to the accumulation of 40,000 total flight cycles, or within the next 2,300 flight cycles after February 12, 1990 (effective date of AD 90-02-16, amendment 39-6452), whichever occurs later, unless accomplished within the last 700 flight cycles, accomplish the requirements of either paragraph (a)(1) or (a)(2) of this AD.
(1) Perform a detailed visual inspection to detect cracks in the front spar web, in accordance with Figure 1 of Boeing Service Bulletin 727-57-0177, dated December 22, 1988; Revision 1, dated November 21, 1991; Revision 2, dated September 16, 1993; Revision 3, dated February 15, 1996; or Revision 4, dated October 28, 1999. Repeat the detailed visual inspection thereafter at intervals not to exceed 3,000 flight cycles, until accomplishment of the requirements specified in either paragraph (b) or (c) of this AD.
Note 2: For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
(2) Perform a high frequency eddy current (HFEC) inspection to detect cracks in the front spar web, in accordance with Boeing Service Bulletin 727-57-0177, Revision 4, dated October 28, 1999. Repeat the HFEC inspection thereafter at intervals not to exceed 4,500 flight cycles, until accomplishment of the requirements specified in either paragraph (b) or (c) of this AD.
Note 3: Accomplishment of the high frequency eddy current (HFEC) inspection required by AD 90-02-16, is considered acceptable for compliance with the initial detailed visual inspection required by paragraph (a) of this AD.
(b) If any crack is detected during any inspection required by paragraph (a) of this AD, prior to further flight, accomplish the actions specified in either paragraph (b)(1) or (b)(2) of this AD, as applicable. Accomplishment of the repair constitutes terminating action for the repetitive inspection requirements of paragraph (a) of this AD for that repaired area.
(1) For airplanes equipped with integral fuel tanks in the center section of the wings: Repair in accordance with Figure 2 of Boeing Service Bulletin 727-57-0177, Revision 3, dated February 15, 1996; or Revision 4, dated October 28, 1999.
(2) For airplanes not equipped with integral fuel tanks in the center section of the wings: Repair in accordance with Figure 2 of Boeing Service Bulletin 727-57-0177, dated December 22, 1988, Revision 1, dated November 21, 1991; Revision 2, dated September 16, 1993; Revision 3, dated February 15, 1996; or Revision 4, dated October 28, 1999.
Note 4: Where there are differences between the referenced service bulletins and this AD, the AD prevails.
(c) Except as provided by paragraph (d) of this AD, prior to the accumulation of 60,000 total flight cycles, or within 48 months after the effective date of this AD, whichever occurs later, accomplish the actions specified in either paragraph (c)(1) or (c)(2) of this AD, as applicable. Accomplishment of this action constitutes terminating action for the repetitive inspection requirements of paragraph (a) of this AD.
(1) For airplanes equipped with integral fuel tanks in the center section of the wings: Modify the front spar web, between the upper and lower seals, of the center section of the wings, in accordance with Part I of the Accomplishment Instructions of Boeing Service Bulletin 727-57-0177, Revision 3, dated February 15, 1996; or Revision 4, dated October 28, 1999.
(2) For airplanes not equipped with integral fuel tanks in the center section of the wings: Modify the front spar web, between the upper and lower seals, of the center section of the wings, in accordance with Boeing Service Bulletin 727-57-0177, dated December 22, 1988, Revision 1, dated November 21, 1991; Revision 2, dated September 16, 1993; Revision 3, dated February 15, 1996; or Revision 4, dated October 28, 1999.
(d) For areas on which the front spar web between the upper and lower seals of the center section of the wings has been repaired or modified in accordance with Figure 2 or 3 of Boeing Service Bulletin 727-57-0177, dated December 22, 1988; Revision 1, dated November 21, 1991; or Revision 2, dated September 16, 1993: Accomplish the actions required by either paragraph (d)(1) or (d)(2) of this AD, as applicable.
(1) For airplanes not equipped with integral fuel tanks in the center section of the wings: No further action is required by this AD for those areas repaired or modified.
(2) For airplanes equipped with integral fuel tanks in the center section of the wings: Accomplish the actions required by both paragraphs (d)(2)(i) and (d)(2)(ii) of this AD.
(i) Within 500 flight cycles after the effective date of this AD, perform a detailed visual inspection of the front spar web to detect fuel leakage and penetrations in the secondary fuel barrier, and to verify the installation of the secondary fuel barrier; in accordance with Boeing Service Bulletin 727-57-0177, Revision 3, dated February 15, 1996; or Revision 4, dated October 28, 1999. Repeat the visual inspection thereafter at intervals not to exceed 1,500 flight cycles, until accomplishment of the actions required by paragraph (d)(2)(ii) of this AD.
(ii) Prior to the accumulation of 14,000 flight cycles, or within 96 months after the effective date of this AD, whichever occurs later, repair/modify the front spar web in accordance with Part II of the Accomplishment Instructions of Boeing Service Bulletin 727-57-0177, Revision 3, dated February 15, 1996; or Revision 4, dated October 28, 1999. Accomplishment of this action constitutes terminating action for the repetitive inspection requirements of paragraph (d)(2)(i) of this AD for that repaired/modified area.
(e) During any inspection required by paragraph (d)(2)(i) of this AD, if any fuel leakage or penetration in the secondary fuel barrier is detected, or if any secondary fuel barrier is verified as not being installed, prior to further flight, repair in accordance with Part II of the Accomplishment Instructions of Boeing Service Bulletin 727-57-0177, Revision 3, dated February 15, 1996; or Revision 4, dated October 28, 1999. Accomplishment of this action constitutes terminating action for the repetitive inspection requirements of paragraph (d)(2)(i) of this AD for that repaired area.
(f) Accomplishment of the actions required by paragraph (b), (c), (d)(2)(ii), or (e) of this AD constitutes terminating action for the requirements specified in paragraph (a) of AD 94-05-04, amendment 39-8842 (59 FR 13442, March 22, 1994), with respect to the modification specified in Boeing Service Bulletin 727-57-0177, dated December 22, 1988. This service bulletin is one of many service bulletins referenced in Boeing Document D6-54860, Revision G, Appendix A.3, dated March 5, 1993. All other service bulletins referenced in that document still apply.
(g)(1) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.
Note 5: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.
(2) For airplanes not equipped with integral fuel tanks in the center section of the wings: Alternative methods of compliance, approved previously in accordance with AD 90-02-16, amendment 39-6452, are approved as alternative methods of compliance with this AD. For airplanes equipped with integral fuel tanks in the center section of the wings: Alternative methods of compliance, approved previously in accordance with AD 90-02-16, are NOT approved as alternative methods of compliance with this AD.
