[Federal Register Volume 67, Number 29 (Tuesday, February 12, 2002)]
[Rules and Regulations]
[Pages 6372-6374]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-2928]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-332-AD; Amendment 39-12636; AD 2002-02-08]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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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.

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.

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

[[Page 6373]]

not 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

[[Page 6374]]

that 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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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

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


Sec. 39.13  [Amended]

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

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 
Secs. 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.

    Issued in Renton, Washington, on January 31, 2002.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-2928 Filed 2-11-02; 8:45 am]
BILLING CODE 4910-13-U