[Federal Register Volume 65, Number 2 (Tuesday, January 4, 2000)]
[Rules and Regulations]
[Pages 205-207]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-11]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-NM-241-AD; Amendment 39-11486; AD 99-27-05]
RIN 2120-AA64
Airworthiness Directives; Boeing Model 767-200, -300, and -300F
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 767-200, -300, and -300F series
airplanes, that requires replacement of the hydraulic reducer fitting
in the return port of the alternate brake selector valve with a new
restrictor fitting. This amendment is prompted by a report indicating
that a brake housing had fractured due to high loads associated with
brake vibration during landing gear retraction, which allowed the
torque rod to swing free. The actions specified by this AD are intended
to prevent failure of the brake housing in the torque rod region, which
could reduce the braking capability of the airplane and/or prevent the
extension of a main landing gear by any method.
DATES: Effective February 8, 2000.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of February 8, 2000.
ADDRESSES: The service information referenced in this AD may be
obtained from Boeing Commercial Airplane
[[Page 206]]
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: David Herron, Aerospace Engineer,
Systems and Equipment Branch, ANM-130S, FAA, Transport Airplane
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue,
SW., Renton, Washington 98055-4056; telephone (425) 227-2672; 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 767-200, -
300, and -300F series airplanes was published in the Federal Register
on August 4, 1998 (63 FR 41481). That action proposed to require
replacement of the hydraulic reducer fitting in the return port of the
alternate brake selector valve with a new restrictor fitting.
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.
Support for the Proposal
One commenter concurs with the requirements of the proposed AD. The
Air Transport Association (ATA) of America states that one of its
members does not currently operate any airplanes affected by the
proposed rule, and another member has no objection to the proposed
rule.
Request To Revise the Discussion Section
One commenter states that it does not agree that the brake
vibration is caused by excessive flow of hydraulic fluid into the
alternate system metering valves during gear retract braking, as
described in the Discussion section of the proposed AD. The commenter
contends that the gear retract braking system, common to Model 757,
747-400, and 777 series airplanes, and to Model 767 series airplanes
equipped with steel brakes, has demonstrated trouble-free service
experience in all of those airplane models without brake vibration. The
brake vibration that has occurred during gear retract braking on Model
767 series airplanes equipped with Boeing part number (P/N) S160T300-
series carbon brakes is attributed to the friction-material
characteristics of the carbon brakes. Reducing the brake-pressure onset
rate consistently reduces peak brake-torque amplitudes and brake
vibration levels, when present.
The new carbon brake, Boeing P/N S160T4000-210, for Model 767
series airplanes, uses a new carbon heatsink that has demonstrated
extremely stable dynamic characteristics during laboratory and flight
tests. Therefore, replacement of the existing carbon brakes, P/N
S160T300-series, with the new carbon brake will, in itself, alleviate
the high loads associated with brake vibration, without replacing the
hydraulic restrictor fitting. The commenter recommends revising the
Discussion section to read ``Brake vibration during gear retract
braking can be reduced on the existing carbon brakes by reducing the
hydraulic flow to the brakes.''
The FAA does not concur that the cause of the brake vibration on
Model 767-200, -300, and -300F series airplanes is due to the brake
material and not the gear retract braking system. In addition, it is
not necessary to revise the Discussion section, as that section does
not appear in the final rule.
Because the brake system comprises a group of components that
include the brake friction material and gear retract brakes, which are
subsets of the brake system, the FAA considers each component to be a
contributor to the unsafe condition. Additionally, Boeing Service
Bulletin 767-32-0152, dated June 6, 1996, and Revisions 1 and 2 of that
service bulletin, do not specify that the cause of the vibration is the
brake material, but only that the vibration occurs in airplanes
equipped with carbon brakes. In fact, the third paragraph of the
Summary section of Revision 1 of the service bulletin states that
``Installation of the restrictor fitting will reduce the flow into the
alternate-system metering valves during gear retract braking. This will
reduce peak torque levels and vibration of the landing gear during
retract braking.''
Request To Change the Applicability of the Proposal
The commenter states that since the brake vibration is associated
only with P/N S160T300-series carbon brakes, the applicability of the
AD should be revised to read ``Model 767-200, -300, and 300F series
airplanes equipped with P/N S160T300-series carbon brakes; certified in
any category.'' The FAA infers that the commenter considers that it is
a combination of carbon brake material and the excessive onset of
hydraulic pressure that results in the unsafe condition; and that
brakes manufactured with a ceram-metallic composite, while benefiting
from the change, do not exhibit the unsafe condition the FAA seeks to
correct through the issuance of this AD.
The FAA concurs that the brake vibration is associated only with
airplanes equipped with Boeing P/N S160T300-series carbon brakes. The
FAA also agrees with the manufacturer that including the specified part
number in the applicability of the final rule correctly identifies
those airplanes with the unsafe condition, and has revised the final
rule accordingly. (The applicability of this AD continues to include
the same airplanes ``1 through 607 inclusive;'' however, the term
``line positions,'' which was used in the proposed AD, has been changed
to ``line numbers'' in this AD.)
Request To Revise Certain Terminology
One commenter states that, with reference to an alternative means
(method) of compliance (AMOC), an ``equivalent'' level of safety rather
than an ``acceptable'' level of safety should be considered. The
commenter provides no justification for its request.
The FAA does not concur that the level of safety should be
specified as ``equivalent'' rather than ``acceptable.'' When
considering any AMOC request, the Manager of the Seattle Aircraft
Certification Office evaluates the request and determines whether the
proposed AMOC request is acceptable (i.e., whether the proposed AMOC
adequately addresses the unsafe condition). If so, the manager approves
the request, even if it is not technically ``equivalent'' to the method
of compliance required by the AD. No change to the final rule is
necessary.
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 change previously
described. The FAA has determined that this change will neither
increase the economic burden on any operator nor increase the scope of
the AD.
Cost Impact
There are approximately 373 Model 767-200, -300, and -300F series
airplanes of the affected design in the worldwide fleet. The FAA
estimates that 86 airplanes of U.S. registry will be affected by this
AD, that it will take approximately 4 work hours per airplane to
accomplish the required actions, and that the average labor rate
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is $60 per work hour. Required parts will cost approximately $104 per
airplane. Based on these figures, the cost impact of the AD on U.S.
operators is estimated to be $29,584, or $344 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 that no operator would accomplish those actions in the
future if this AD were not adopted.
Regulatory Impact
The regulations adopted herein will not have substantial direct
effects 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, in
accordance with Executive Order 12612, it is determined that this final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
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:
99-27-05 Boeing: Amendment 39-11486. Docket 97-NM-241-AD.
Applicability: Model 767-200, -300, and -300F series airplanes,
line numbers 1 through 607 inclusive; equipped with part number
S160T300-series carbon brakes; 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 (b) 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 brake housing in the torque rod
region, which could reduce the braking capability of the airplane
and/or prevent the extension of a main landing gear, accomplish the
following:
Replacement
(a) Within 360 days after the effective date of this AD, replace
the hydraulic reducer fitting in the return port of the alternate
brake selector valve with a new restrictor fitting, in accordance
with Boeing Service Bulletin 767-32-0152, dated June 6, 1996;
Revision 1, dated June 27, 1996; or Revision 2, dated July 10, 1997.
Alternative Methods of Compliance
(b) 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.
Special Flight Permits
(c) 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
(d) The replacement shall be done in accordance with Boeing
Service Bulletin 767-32-0152, dated June 6, 1996; Boeing Service
Bulletin 767-32-0152, Revision 1, dated June 27, 1996; or Boeing
Service Bulletin 767-32-0152, Revision 2, dated July 10, 1997. 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.
(e) This amendment becomes effective on February 8, 2000.
Issued in Renton, Washington, on December 22, 1999.
Vi L. Lipski,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 00-11 Filed 1-3-00; 8:45 am]
BILLING CODE 4910-13-U
