Applicability: All Model 737-100, -200, -300, -400, and -500 series airplanes; certificated in any category.

Effective date: July 15, 1999

Compliance: Required as indicated in FAA AD 99-10-12.

Remarks: Where applicable, the requirements of this AD must be integrated into the Aircraft's Logbook(s). Address inquiries concerning this AD to: Civil Aviation Authority, Airworthiness Division, Ruzyne Airport, 160 08 Prague 6, Czech Republic, tel.: 420 2 33320922, fax: 420 2 20562270.

99-10-12 BOEING: Amendment 39-11165. Docket 99-NM-68-AD. Supersedes AD 91-05-16, Amendment 39-6913.

Applicability: All Model 737-100, -200, -300, -400, and -500 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 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 (d) 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 detect and correct corrosion and cracking of the actuator beam arm of the main landing gear (MLG), which could result in damage to the control cables of the aileron and spoiler and consequent reduced controllability of the airplane, accomplish the following:

(a) For airplanes listed in Boeing Alert Service Bulletin 737-32A1224, Revision 1, dated April 12, 1990: Prior to the accumulation of 10,000 landings or 4 years of service, after new or overhauled MLG installation, whichever occurs first, or within the next 600 landings after April 1, 1991 (the effective date of AD 91-05-16, amendment 39-6913), whichever occurs later, perform visual and ultrasonic inspections of the actuator beam arm clevis for evidence of cracking, in accordance with Boeing Alert Service Bulletin 737-32A1224, Revision 1, dated April 12, 1990, or Revision 2, dated April 25, 1991.

(1) If cracks are found, prior to further flight, remove and rework, or replace, the actuator beam arm in accordance with the service bulletin.

(2) If no cracks are found, repeat the ultrasonic inspections in accordance with the service bulletin, at intervals not to exceed 600 landings, until the initial inspection required by paragraph (b) of this AD has been accomplished.

(b) Inspect the actuator beam arm clevis, by performing a detailed visual inspection to detect corrosion and an ultrasonic inspection to detect cracking, at the latest of the times specified in paragraphs (b)(1), (b)(2), (b)(3), and (b)(4) of this AD; in accordance with Boeing Alert Service Bulletin 737-32A1314, dated April 15, 1999. Accomplishment of these inspections constitutes terminating action for the requirements of paragraph (a) of this AD. Repeat the inspections specified by paragraph (b) of this AD thereafter at intervals not to exceed 90 days.

(1) Inspect within 4 years since date of manufacture or installation of new landing gear.

(2) Inspect within 4 years since the most recent landing gear overhaul.

(3) Inspect within 4 years since accomplishment of the replacement of the actuator beam arm clevis performed in accordance with the alert service bulletin, or the rework performed in accordance with Boeing Alert Service Bulletin 737-32A1224, Revision 1, dated April 12, 1990, or Boeing Service Bulletin 737-32A1224, Revision 2, dated April 25, 1991.

(4) Inspect within 90 days after the effective date of this AD.

NOTE 2: The NOTE in Figure 1 of Boeing Alert Service Bulletin 737-32A1314 contains a reference to Temporary Revision (TR) 04-14 to the 737 Nondestructive Test Manual (NDT). The TR was issued April 26, 1999, by telegraphic release. The TR provides instructions for procuring or fabricating NDT transducers needed to accomplish ultrasonic inspections on airplanes having certain actuator beam arm assemblies. Incorporation of the TR into the general revisions of the NDT is acceptable, provided that the information contained in the general revisions is identical to that specified in the TR.

(c) If any corrosion or cracking is detected during any inspection required by paragraph (b) of this AD, prior to further flight, replace the actuator beam arm with a new actuator beam arm in accordance with Boeing Alert Service Bulletin 737-32A1314, dated April 15, 1999. Repeat the inspections required by paragraph (b) of this AD within 4 years after accomplishment of the replacement, and thereafter at intervals not to exceed 90 days.

(d) 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). 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

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

(f) The actions shall be done in accordance with Boeing Alert Service Bulletin 737-32A1224, Revision 1, dated April 12, 1990; Boeing Service Bulletin 737-32A1224, Revision 2, dated April 25, 1991; or Boeing Alert Service Bulletin 737-32A1314, dated April 15, 1999; as applicable. 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.

(g) This amendment becomes effective on May 27, 1999.

FOR FURTHER INFORMATION CONTACT:

Rick Kawaguchi, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1153; fax (425) 227-1181.