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Airworthiness Directives; Boeing Model 737-200, -200C, -300, and -500 Series Airplanes

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Information about this document as published in the Federal Register.

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Start Preamble

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-200, -200C, -300, and -500 series airplanes, that requires replacement of the bolt and self-locking nut on the primary support pin of the main landing gear (MLG) support beam with a new bolt, castellated nut, washer, and cotter pin. This action is necessary to prevent the loosening and loss of the support pin retaining bolt on the MLG, which could result in the loosening and movement of the support pin and consequent cracked support fittings and collapse of the MLG. This action is intended to address the identified unsafe condition.

DATES:

Effective March 19, 2002.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of March 19, 2002.

ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

James Blilie, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2131; fax (425) 227-1181.

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SUPPLEMENTARY INFORMATION:

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 737-200, -200C, -300, and -500 series airplanes was published in the Federal Register on July 25, 2001 (66 FR 38587). That action proposed to require replacement of the bolt and self-locking nut on the primary support pin of the main landing gear (MLG) support beam with a new bolt, castellated nut, washer, and cotter pin.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Refer to New Service Information

One commenter, the airplane manufacturer, requests that the FAA revise the proposed AD to refer to Boeing Service Bulletin 737-57A1260, Revision 2, dated October 18, 2001, as the acceptable source of service information for the proposed actions. (The proposed AD refers to the original issue of the service bulletin, dated June 15, 2000, and Revision 1 of the service bulletin, dated October 12, 2000, as appropriate sources of service information for the proposed actions.)

The FAA concurs. Since the issuance of the proposed AD, we have reviewed and approved Revision 2 of the service bulletin. This revision provides significant detailed information on which airplanes need the work described in the service bulletin and which do not. For example, the actions in Boeing Service Bulletin 737-57A1260, Revision 2, do not apply to airplanes in Groups 3 and 4, as listed in the service bulletin, if the airplane has been modified per Boeing Service Bulletin 737-57-1172, dated October 15, 1987; OR Boeing Service Bulletin 737-57-1216, dated December 17, 1992, Revision 1, dated September 23, 1993, or Revision 2, dated May 6, 1999 (but not both of those service bulletins). Revision 2 of the service bulletin also provides instructions for certain airplanes in alternative configurations. Because these changes are relieving in nature, we find that it is appropriate to revise paragraph (a), as well as the applicability statement, of this final rule to refer to Revision 2 of the service bulletin. We have also added a new Note 2 to this AD (and reordered a subsequent note accordingly) to state that accomplishment of the actions before the effective date of this AD per the original issue or Revision 1 of Boeing Service Bulletin 737-57A1260 is acceptable for compliance with paragraph (a) of this AD.

Another commenter reports that, when it tried to do Boeing Service Bulletin 737-57A1260 on an affected airplane, it found that the bolt sizes identified in that service bulletin did Start Printed Page 6373not match parts included with the associated kit. The commenter asks how Boeing will revise the service bulletin. We infer that the commenter attempted to accomplish the original issue or Revision 1 of the service bulletin, and we also infer that the commenter's airplane is one of the airplanes of alternative configuration which are acknowledged in Revision 2 of the service bulletin. We note that revising the final rule as described previously will positively address the commenter's concern, and no further change to the final rule is needed in this regard.

A third commenter requests that we revise the proposed AD to refer to Boeing Alert Service Bulletin 737-57A1260, Information Notice (IN) 02. The commenter notes that this IN contains information about alternative configurations and methods related to the installation of the castellated nut and cotter pin. We note that the data in the IN to which the commenter refers have been incorporated into Boeing Service Bulletin 737-57A1260, Revision 2; thus, no further change to the final rule is needed.

Acknowledge Other Configurations

One commenter requests that we revise the proposed AD to state that accomplishment of Boeing Service Bulletin 737-57-1172 or 737-57-1216 is equivalent to the accomplishment of the original issue or Revision 1 of Boeing Alert Service Bulletin 737-57A1260. Along with its comment, the commenter includes a copy of a telex from the airplane manufacturer which indicates that a castellated nut with a cotter pin through the bolt shank meets the intent of Boeing Service Bulletin 737-57A1260.

We concur with the intent of the commenter's request. Airplanes in certain configurations, as defined under paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-57A1260, Revision 2, are not subject to the requirements of this AD. Therefore, we have added a new paragraph (b) to this AD (and reordered subsequent paragraphs accordingly) to clarify that airplanes in the configurations specified in Revision 2 are not subject to this AD. In addition, for clarification, we have revised paragraph (a) of this AD to specify that the existing parts to be replaced are a RETAINING bolt, a SELF-LOCKING nut, and associated hardware.

Refer to Related Service Bulletin

One commenter, the airplane manufacturer, requests that the FAA revise the proposed AD to explicitly caution operators that accomplishment of the actions in Boeing Service Bulletin 737-57-1216 may result in installation of self-locking nuts that are the subject of this AD. The commenter asserts that the sequencing of Boeing Service Bulletins 737-57-1216 and 737-57A1260 is critical. The commenter points out that the relationship between these service bulletins is noted in Boeing Service Bulletin 737-57-1216, Revision 2, IN 04, dated October 12, 2000. (That IN informs operators of certain airplanes that, if they do Boeing Service Bulletin 737-57-1216, they may be subject to Boeing Service Bulletin 737-57A1260.)

We concur with the commenter's request. While operators are responsible for installing only approved parts, we acknowledge that it may be helpful to advise operators of a related service bulletin that may conflict with the actions in this AD. We have added Note 1 to this final rule accordingly.

Limit Applicability

One commenter states that, if the unsafe condition exists only in “a batch of Kaynar nuts,” as stated in the referenced service bulletin, then the applicability of the proposed AD should be limited to airplanes built in the time period when that batch of nuts was used.

The FAA infers that the commenter is requesting that the applicability of this AD be limited. We note that the revision of the applicability to refer to Revision 2 of the service bulletin, as described previously, may address the commenter's concern, and we do not concur that any further change to this final rule needs to be made. The airplanes listed in the Effectivity section of the referenced service bulletin are those that the airplane manufacturer cannot be certain do not have affected nuts installed. While only certain airplanes included in the applicability of this AD will have discrepant nuts installed, neither we nor the airplane manufacturer are able to narrow the list of potentially affected airplanes any further than it has already been narrowed by Boeing Service Bulletin 737-57A1260, Revision 2.

Extend Compliance Time

Several commenters request that the FAA extend the compliance time for the proposed replacement. One commenter suggests only extension of the compliance time from the earlier of 12 months or 1,500 flight cycles after the effective date of the AD, to the earlier of 24 months or 4,000 flight cycles after the effective date of the AD. Three other commenters suggest adding new repetitive inspections for discrepancies of the nut and bolt at the proposed compliance time of the earlier of 12 months or 1,500 flight cycles after the effective date of the AD, and requiring the proposed replacement at the earlier of 24 months or 4,500 flight cycles after the effective date of the AD. Most of the commenters state that such an extension would ease scheduling difficulties by allowing affected operators to accomplish the proposed replacement at a scheduled maintenance visit.

We do not concur with the commenters' requests. The commenters provide no technical justification to show that extension of the compliance time would provide an acceptable level of safety. While the compliance time for the replacement required by this AD is based on the manufacturer's recommendation in its service bulletin, the FAA also considered the degree of urgency associated with addressing the subject unsafe condition and the average utilization of the affected fleet in developing an appropriate compliance time for this action. In light of all of these factors, the FAA finds a compliance time of 12 months or 1,500 flight cycles after the effective date of this AD, whichever is earlier, for completing the required actions to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety. No change to the final rule is needed in this regard.

Conclusion

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact

There are approximately 2,300 Model 737-200, -200C, -300, and -500 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 980 airplanes of U.S. registry will be affected by this AD, that it will take approximately 6 work hours per airplane to accomplish the replacement, and that the average labor rate is $60 per work hour. Required parts will cost approximately $39 per airplane. Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $391,020, or $399 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and Start Printed Page 6374that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations adopted herein will not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this action (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES.

Start List of Subjects

List of Subjects in 14 CFR Part 39

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Adoption of the Amendment

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Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (

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PART 39—AIRWORTHINESS DIRECTIVES

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1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]
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2. Section 39.13 is amended by adding the following new airworthiness directive:

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2002-02-08 Boeing: Amendment 39-12636. Docket 2000-NM-332-AD.

Applicability: Model 737-200, -200C, -300, and -500 series airplanes; as identified in Boeing Service Bulletin 737-57A1260, Revision 2, dated October 18, 2001; certificated in any category.

Note 1:

Operators should note that, if self-locking nuts are installed on the support beam for the main landing gear (MLG) during accomplishment of Boeing Service Bulletin 737-57-1216, dated December 17, 1992; Revision 1, dated September 23, 1993; or Revision 2, dated May 6, 1999; the airplane may be subject to the requirements of this AD.

Note 2:

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 (c) 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 the loosening and loss of the support pin retaining bolt on the MLG, which could result in the loosening and movement of the support pin, consequent cracked support fittings, and collapse of the MLG, accomplish the following:

Replacement

(a) Within 12 months from the effective date of this AD, or within 1,500 flight cycles from the effective date of this AD, whichever occurs first, replace the retaining bolt, self-locking nut, and associated hardware of the support beam for the MLG with a new bolt, castellated nut, and new hardware, per the Accomplishment Instructions of Boeing Service Bulletin 737-57A1260, Revision 2, dated October 18, 2001.

Note 3:

Replacements accomplished before the effective date of this AD per Boeing Alert Service Bulletin 737-57A1260, dated June 15, 2000; or Revision 1, dated October 12, 2000; are acceptable for compliance with paragraph (a) of this AD.

Airplanes in Other Configurations

(b) As shown under paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-57A1260, Revision 2, dated October 18, 2001, if the airplane is in a configuration in which a drilled shank bolt, castellated nut, and cotter pin are installed in the subject areas of the support beam for the MLG, no action is necessary per this AD.

Alternative Methods of Compliance

(c) 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. 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 4:

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

Special Flight Permits

(d) Special flight permits may be issued in accordance with §§ 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.

Incorporation by Reference

(e) The actions shall be done in accordance with Boeing Service Bulletin 737-57A1260, Revision 2, dated October 18, 2001. 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.

Effective Date

(f) This amendment becomes effective on March 19, 2002.

Start Signature

Issued in Renton, Washington, on January 31, 2002.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. 02-2928 Filed 2-11-02; 8:45 am]

BILLING CODE 4910-13-U