97-02-09

97-02-09

Main Landing Gear

Category - Airframe
Effective Date - 03/04/1997
Recurring - Yes
Supersedes - 90-02-19 and 93-01-14
Superseded by - N/A
Amendment 39-9894, Docket 95-NM-223-AD.
Supersedes AD 90-02-19, Amendment 39-6433; and supersedes AD 93-01-14, Amendment 39-8368.

Applicability: All Model 727 series airplanes, certificated in any category.

Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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) 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.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the main landing gear (MLG) to extend for landing and subsequent damage to the airplane, accomplish the following:

(a) For airplanes equipped with rib fittings that have been modified (reworked) in accordance with Boeing Service Bulletin 727-32-0364, dated December 15, 1988, or Revision 1, dated October 19, 1989; but have not been modified in accordance with Figure 2 of Boeing Service Bulletin 727-32-0383, Revision 1, dated January 30, 1992: Accomplish the following:

(1) Prior to the accumulation of 1,000 flight cycles after the effective date of this AD, accomplish the actions specified in both paragraphs (a)(1)(i) and (a)(1)(ii):

(i) Perform either a high frequency eddy current or dye penetrant inspection to detect cracking of the actuator rib fitting of the MLG, in accordance with Part I of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995. And

(ii) Inspect the actuator rib fitting of the MLG to ensure that serrations are fully mated, and to detect loose bolts, in accordance with Figure 1 of Boeing Service Bulletin 727-32-0383, Revision 1, dated January 30, 1992.

(2) If the inspections required by paragraph (a)(1) of this AD reveal no cracking or loose bolts, and reveal that the serrations are fully mated, accomplish the actions specified in paragraphs (a)(2)(i), (a)(2)(ii), and (a)(2)(iii) of this AD:

(i) Prior to further flight, re-rig the door in accordance with the maintenance manual procedures referenced in Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995, to ensure proper door rigging. And

(ii) Thereafter, repeat the inspections required by paragraph (a)(1) of this AD at intervals not to exceed 1,000 flight cycles until the modification required by paragraph (a)(2)(iii) of this AD is accomplished; and

(iii) Prior to the accumulation of 3,000 flight cycles after the effective date of this AD, modify the actuator rib fitting in accordance with Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995. As an option to the action specified in Step 1 of Figure 3 of that alert service bulletin, operators may layout a .39-inch minimum radius.

(3) If the inspections required by paragraph (a)(1) of this AD reveal no cracking, but do reveal loose bolts or serrations that are not fully mated, prior to further flight accomplish either paragraph (a)(3)(i)or (a)(3)(ii) of this AD:

(i) Modify the actuator rib fitting in accordance with Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995. As an option to the action specified in Step 1 of Figure 3 of that alert service bulletin, operators may layout a .39-inch minimum radius. Or

(ii) Replace the currently-installed aluminum rib fitting with a new steel rib fitting, in accordance with Part III of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995. After this replacement, no further action is required by this AD for that rib fitting.

(b) For airplanes equipped with rib fittings that have been modified in accordance with Boeing Service Bulletin 727-32-0364, dated December 15, 1988, or Revision 1, dated October 19, 1989; and have been modified in accordance with Figure 2 of Boeing Service Bulletin 727-32-0383, Revision 1, dated January 30, 1992: Accomplish the following:

(1) Perform either a high frequency eddy current or dye penetrant inspection to detect cracking of the actuator rib fitting of the MLG, in accordance with Part I of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995, at the later of the times specified in either paragraph (b)(1)(i), (b)(1)(ii), or (b)(1)(iii) of this AD.

(i) Prior to the accumulation of 1,000 flight cycles after the effective date of the AD; or

(ii) Within 2,500 flight cycles after the immediately preceding inspection performed in accordance with Boeing Service Bulletin 727-32A0399; or

(iii) Within 5,000 flight cycles after accomplishing the terminating action in accordance with AD 93-01-14.

(2) If no cracking is detected during the inspection required by paragraph (b)(1) of this AD, accomplish the actions specified in paragraphs (b)(2)(i), (b)(2)(ii), and (b)(2)(iii) of this AD:

(ii) Thereafter, repeat the inspection required by paragraph (b)(1) at intervals not to exceed 2,500 flight cycles until the modification required by paragraph of (b)(2)(iii) this AD is accomplished; and

(iii) Prior to the accumulation of 6,000 flight cycles after the effective date of this AD, modify the actuator rib fitting in accordance with Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995. As an option to the action specified in Step 1 of Figure 3 of that alert service bulletin, operators may layout a .39-inch minimum radius.

(c) For airplanes equipped with rib fittings that have not been modified in accordance with Boeing Service Bulletin 727-32-0364, dated December 15, 1988, or Revision 1, dated October 19, 1989: Accomplish the following:

(1) Prior to the accumulation of 1,000 flight cycles after the effective date of this AD, accomplish the actions specified in both paragraphs (c)(1)(i) and (c)(1)(ii) of this AD:

(2) If the inspections required by paragraph (c)(1) of this AD reveal no cracking or loose bolts, and reveal that the serrations are fully mated, prior to further flight, accomplish the actions specified in either paragraph (c)(2)(i), (c)(2)(ii), or (c)(2)(iii) of this AD:

(i) Modify the actuator rib fitting in accordance with Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995; and in accordance with Boeing Service Bulletin 727-32-0364, dated December 15, 1988, or Revision 1, dated October 19, 1989. As an option to the action specified in Step 1 of Figure 3 of Boeing Alert Service Bulletin 727-32A0399, operators may layout a .39-inch minimum radius. Or

(iii) Replace the fitting with a like fitting that has been inspected in accordance with Part I of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995; and modified in accordance with Part II of the Accomplishment Instructions of that service bulletin and in accordance with Boeing Service Bulletin 727-32-0364, dated December 15, 1988, or Revision 1, dated October 19, 1989.

(d) If any cracking is detected during the inspections required by paragraphs (a)(1), (b)(1), or (c)(1) of this AD, prior to further flight, accomplish the actions specified in either paragraph (d)(1) or (d)(2) of this AD:

(1) Replace the cracked fitting with a like fitting that has been inspected in accordance with Part I of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995; and modified in accordance with Part II of the Accomplishment Instructions of that service bulletin and in accordance with Boeing Service Bulletin 727-32-0364, dated December 15, 1988, or Revision 1, dated October 19, 1989. As an option to the action specified in Step 1 of Figure 3 of Boeing Alert Service Bulletin 727-32A0399, operators may layout a .39-inch minimum radius. Or

(2) Replace the cracked fitting with a new steel rib fitting in accordance with Part III of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995. This replacement constitutes terminating action for the requirements of that AD for that fitting.

(e) For all airplanes on which modification of the actuator rib fitting has been accomplished in accordance with Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995; and Boeing Service Bulletin 727-32-0364, dated December 15, 1988, or Revision 1, dated October 19, 1989: Within 7,500 flight cycles after accomplishing the modification, accomplish the following:

(1) Perform either a high frequency eddy current or dye penetrant inspection to detect cracking of the modified actuator rib fitting, in accordance with the alert service bulletin.

(2) Repeat the inspection thereafter at intervals not to exceed 2,500 flight cycles until the fitting is replaced with a new steel rib fitting, in accordance with Part III of the Accomplishment Instructions of the alert service bulletin. This replacement constitutes terminating action for the requirements of this AD for that fitting.

(f) Replacement of aluminum actuator rib fittings with new steel actuator rib fittings in accordance with Part III of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995, constitutes terminating action for the requirements of this AD.

(g) 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 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

(h) Special flight permits may be issued in accordance with sections FAR 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR FAR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

(i) The actions shall be done in accordance with Boeing Alert Service Bulletin 727-32A0399, dated July 13, 1995. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(j) This amendment becomes effective on March 4, 1997.

FOR FURTHER INFORMATION CONTACT:

Walter Sippel, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington; telephone (206) 227-2774; fax (206) 227-1181.