[Federal Register Volume 65, Number 183 (Wednesday, September 20, 2000)]
[Rules and Regulations]
[Pages 56783-56785]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-23856]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-69-AD; Amendment 39-11906; AD 2000-19-05]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD); applicable to certain Boeing Model 737-100, -200, -200C, -300, -
400, and -500 series airplanes; that currently requires a one-time 
inspection of the attachment nuts at each end attachment of the 
elevator tab push rods to measure run-on torque values, and corrective 
actions, if necessary. This amendment adds a requirement to replace all 
existing bolts and attachment nuts at the forward and aft end 
attachment of each elevator tab push rod with new bolts and self-
locking castellated nuts with cotter pins. This amendment is prompted 
by reports of excessive high-frequency airframe vibration during 
flight, with consequent structural damage to the elevator tab, 
elevator, and stabilizer. The actions specified by this AD are intended 
to prevent detachment of an elevator tab push rod due to a detached nut 
at either end attachment of a push rod, which could result in excessive 
high-frequency airframe vibration during flight; consequent structural 
damage to the elevator tab, elevator, and horizontal stabilizer; and 
reduced controllability of the airplane.

DATES: Effective October 25, 2000.
    The incorporation by reference of Boeing Service Letter 737-SL-27-
118-D, dated December 17, 1999, as listed in the regulations, is 
approved by the Director of the Federal Register as of October 25, 
2000.
    The incorporation by reference of Boeing Alert Service Bulletin 
737-27A1205, dated August 28, 1997, was approved previously by the 
Director of the Federal Register as of March 23, 1999 (64 FR 10935, 
March 8, 1999).

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: Scott Fung, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
227-1221; fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 99-05-15, 
amendment 39-11063 (64 FR 10935, March 8, 1999); applicable to certain 
Boeing Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes; was published in the Federal Register on December 3, 1999 
(64 FR 67807). The action proposed to continue to require a one-time 
inspection of the attachment nuts at each end attachment of the 
elevator tab push rods to measure run-on torque values, and corrective 
actions, if necessary. The action also proposed to add a requirement to 
replace all existing bolts and attachment nuts at the forward and aft 
end attachment of each elevator tab push rod with new bolts and self-
locking castellated nuts with cotter pins.

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.

Supportive Comment

    One commenter supports the proposed rule.

Request To Extend Compliance Time in Paragraph (b)

    Several commenters request that the FAA extend the proposed 
compliance time for the replacement of the existing bolts and 
attachment nuts specified in paragraph (b) of the proposal. One 
commenter requests that the proposed compliance time be extended from 
12 months to 18 months after the effective date of this AD. The 
commenter indicates that an 18-month compliance time will allow the 
work to be incorporated into its regularly scheduled maintenance visits 
when sufficient time and resources are available.
    A second commenter requests that the proposed compliance time be 
extended to within 24 months after the effective date of this AD, not 
to exceed 4,000 flight cycles. The commenter states that this change 
will enable the tab freeplay inspections and tab push rod bolt and nut 
replacement to be made concurrently during a regularly scheduled major 
maintenance check (a ``C'' check). The commenter adds that this change 
also will reduce the impact on fleet operations, a concern operators 
expressed during the lead airline reviews for Boeing Service Bulletin 
737-55A1070, dated January 13, 2000. According to the commenter, 737-
55A1070 specifies that tab installation inspections and tab hinge and 
tab trailing edge freeplay checks be made within 4,000 flight cycles or 
24 months after release of the service bulletin. That service bulletin 
also has repeat inspections at 1,500 flight cycles or 2,000 flight 
hours.
    A third commenter requests an extension of the proposed compliance 
time to 24 months after the effective date of this AD. The commenter 
states that the extension would allow accomplishment of the replacement 
during its heavy maintenance checks.
    A fourth commenter requests an extension of the proposed compliance 
time to 4 years after the effective date of this AD. The commenter 
states that replacement of the hardware cannot be done in a short 
(overnight) maintenance visit. The commenter proposes that the 
compliance time be extended in order to allow the work to be 
accomplished during a major maintenance visit. The commenter currently 
is working on replacing the subject hardware per the accomplishment 
schedule in the proposed rule. The commenter indicates that the 
inspection of the bolts for current run-on torque values specified in 
the proposal has been accomplished on its fleet, and the attachment 
hardware has been replaced if its condition was beyond allowable 
limits. In light of this fact, the commenter notes that an extension of 
the compliance time for the remaining attachments should not pose a 
significant decrease in safety.
    The FAA concurs with the commenters' requests to extend the 
compliance time required by paragraph (b) of the final rule. Following 
careful consideration of the comments, and in light of the fact that AD 
99-05-15, amendment 39-11063, mandated the one-time inspection and 
corrective actions, the FAA has determined that it will not compromise 
safety to extend the compliance time for the replacement required by 
paragraph (b) of this AD.

[[Page 56784]]

Therefore, the compliance time in paragraph (b) of this final rule has 
been extended to within 24 months or 4,000 flight cycles after the 
effective date of this AD, whichever occurs first.

Request To Revise Cost Impact Information

    One commenter states that the actual time required to modify an 
airplane (replace the existing bolts and nuts) is 12 work hours and 
will exceed the 4 work hours estimated in the proposed rule. The 
commenter adds that the modification cannot be done during an overnight 
maintenance visit without disrupting service, and special routing would 
be required.
    The FAA acknowledges that the cost impact information, below, 
describes only the ``direct'' costs of the specific actions required by 
this AD. The estimate of 12 work hours submitted by the commenter 
includes time for gaining access and closing up. The cost analysis in 
AD rulemaking actions, however, typically does not include incidental 
costs, such as the time required to gain access and close up, planning 
time, or time necessitated by other administrative actions. Because 
incidental costs may vary significantly from operator to operator, they 
are almost impossible to calculate. The number of work hours necessary 
to accomplish the required actions, specified as 4 in the cost impact 
information in the proposal and restated below, represents the time 
necessary to perform only the actions actually required by this AD 
(that is, the replacement). No change to the final rule is necessary in 
this regard.

Later Revision of Service Letter

    Two commenters state that the most current revision level of the 
service letter should be used in the proposed rule. The FAA agrees with 
the commenters statement. The FAA has reviewed and approved Boeing 
Service Letters 737-SL-27-118-B, dated April 14, 1999; 737-SL-27-118-C, 
dated May 19, 1999; and 737-SL-27-118-D, dated December 17, 1999; and 
finds that they are essentially similar to the service letter 
referenced in paragraphs (a)(2) and (b) of the proposed rule. 
Accordingly, Revision `D' has replaced the reference to Revision `A' in 
paragraphs (a)(2) and (b) of this AD. In addition, a new note (Note 3) 
has been added to this final rule to give credit for accomplishment of 
the actions in paragraphs (a)(2) and (b) of this AD in accordance with 
Revisions `A,' `B,' or `C' of the service letter prior to the effective 
date of this AD.

Explanation of Change to Proposal

    Since the issuance of the notice of proposed rulemaking (NPRM), the 
FAA has concluded that paragraph (c)(2) of the proposal is incorrect. 
That paragraph reads, ``Alternative methods of compliance (AMOC), 
approved previously in accordance with AD 99-05-15, amendment 39-11063, 
are NOT considered to be approved as alternative methods of compliance 
with this AD.'' The FAA has determined that the AMOC's specified are 
indeed approved. Therefore, paragraph (c)(2) of this final rule has 
been revised accordingly.

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 2,742 airplanes of the affected design in 
the worldwide fleet. The FAA estimates that 1,106 airplanes of U.S. 
registry will be affected by this AD.
    The new replacement that is required in this AD action takes 
approximately 4 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Required parts will cost approximately 
$560 per airplane. Based on these figures, the cost impact of the 
replacement required by this AD on U.S. operators is estimated to be 
$884,800, or $800 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the current or new requirements 
of this AD action, and that no operator would accomplish those actions 
in the future if this AD were not adopted.
    The one-time inspection required by AD 99-05-15 was required to be 
accomplished within 90 days after the effective date of that AD (March 
23, 1999). Since the 90-day compliance time has passed, the FAA assumes 
that all airplanes currently on the U.S. Register have been inspected. 
Therefore, there is no future cost impact of this requirement on 
current U.S. operators of these airplanes.
    However, should an affected airplane be imported and placed on the 
U.S. Register in the future, it would take approximately 4 work hours 
per airplane to accomplish the one-time inspection, at an average labor 
rate of $60 per work hour. Based on these figures, the cost impact of 
the inspection required by this AD on U.S. operators is estimated to be 
$240 per airplane.

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 removing amendment 39-11063 (64 FR 
10935, March 8, 1999), and by adding a new airworthiness directive 
(AD), amendment 39-11906, to read as follows:

2000-19-05  Boeing: Amendment 39-11906. Docket 99-NM-69-AD. 
Supersedes AD 99-05-15, Amendment 39-11063.

    Applicability: Model 737-100, -200, -200C, -300, -400, and -500 
series airplanes; line numbers 1 through 2939 inclusive; 
certificated in any category.


[[Page 56785]]


    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 (c)(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.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent detachment of an elevator tab push rod due to a 
detached nut at either end attachment of a push rod, which could 
result in excessive high-frequency airframe vibration during flight; 
consequent structural damage to the elevator tab, elevator, and 
horizontal stabilizer; and reduced controllability of the airplane; 
accomplish the following:

Restatement of Requirements of AD 99-05-15

One-Time Inspection

    (a) Within 90 days after March 23, 1999 (the effective date of 
AD 99-05-15, amendment 39-11063): Perform a one-time inspection of 
all attachment nuts at each end of each elevator tab push rod to 
measure the run-on torque values of the nuts, in accordance with 
Boeing Alert Service Bulletin 737-27A1205, dated August 28, 1997.

Corrective Actions

    (1) If the run-on torque value of any end attachment nut is 
within the limits specified in the alert service bulletin, prior to 
further flight, ensure that the final seating torque of the 
attachment nuts is within the torque values specified in the alert 
service bulletin.
    (2) If the run-on torque value of any end attachment nut is 
outside the limits specified in the alert service bulletin, prior to 
further flight, replace all existing bolts and attachment nuts at 
each end of each elevator tab push rod with new bolts and self-
locking castellated nuts that have cotter pins installed as a 
secondary locking feature, in accordance with Boeing Service Letter 
737-SL-27-118-D, dated December 17, 1999, and ensure that the final 
seating torque of the nuts is within the torque values specified in 
the service letter.

    Note 2: Accomplishment of the inspection and ensuring adequate 
final seating torque values prior to the effective date of this AD 
in accordance with Boeing All-Base Telex M-7272-97-0897, dated 
February 13, 1997, are considered acceptable for compliance with the 
actions specified in paragraphs (a) and (a)(1) of this AD for only 
the forward attachment nuts.

New Requirements of This AD

Replacement

    (b) Within 12 months or 4,000 flight cycles after the effective 
date of this AD, whichever occurs first: Replace all existing bolts 
and attachment nuts at the forward and aft end attachment of each 
elevator tab push rod with new bolts and self-locking castellated 
nuts that have cotter pins installed as a secondary locking feature, 
in accordance with Boeing Service Letter 737-SL-27-118-D, dated 
December 17, 1999.

    Note 3: Replacements accomplished prior to the effective date of 
this AD in accordance with Boeing Service Letter 737-SL-27-118-A, 
dated November 14, 1997; 737-SL-27-118-B, dated April 14, 1999; or 
737-SL-27-118-C, dated May 19, 1999; are considered acceptable for 
compliance with paragraphs (a)(2) and (b) of this AD.

Alternative Methods of Compliance

    (c)(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. 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.
    (2) Alternative methods of compliance, approved previously in 
accordance with AD 99-05-15, amendment 39-11063, are considered to 
be approved as alternative methods of compliance with paragraph (a) 
of this AD only.

    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 
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.

Incorporation by Reference

    (e) The actions shall be done in accordance with Boeing Alert 
Service Bulletin 737-27A1205, dated August 28, 1997, and Boeing 
Service Letter 737-SL-27-118-D, dated December 17, 1999.
    (1) The incorporation by reference of Boeing Service Letter 737-
SL-27-118-D, dated December 17, 1999, is approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51.
    (2) The incorporation by reference of Boeing Alert Service 
Bulletin 737-27A1205, dated August 28, 1997, was approved previously 
by the Director of the Federal Register as of March 23, 1999 (64 FR 
10935, March 8, 1999).
    (3) 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.
    (f) This amendment becomes effective on October 25, 2000.

    Issued in Renton, Washington, on September 12, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-23856 Filed 9-19-00; 8:45 am]
BILLING CODE 4910-13-P