AD 2001-11-07

[Federal Register Volume 66, Number 112 (Monday, June 11, 2001)]
[Rules and Regulations]
[Pages 31135-31141]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-14000]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-298-AD; Amendment 39-12249; AD 2001-11-07]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737, 757, and 767 Series 
Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 737, 757, and 767 series airplanes. 
This AD requires repetitive operational checks of certain motor-
operated hydraulic shutoff valves to detect malfunctioning; replacement 
with new valves, if necessary; and eventual replacement of certain 
existing valves with new valves, which terminates the repetitive 
inspections. This amendment is prompted by reports that various 
intermittent limit-switch problems have caused valve failures. The 
actions specified by this AD are intended to prevent failure of the 
motor-operated hydraulic shutoff valves, which could result in leakage 
of hydraulic fluid to the engine fire zone, reduced ability to retract 
the landing gear, loss of backup electrical power or other combinations 
of failures; and consequent reduced controllability of the airplane.

DATES: Effective July 16, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 16, 2001.

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: Kenneth W. Frey, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 227-2673; 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, 757, and 
767 series airplanes was published as a supplemental notice of proposed 
rulemaking (NPRM) in the Federal Register on June 21, 2000 (65 FR 
38450). That action proposed to require repetitive operational checks 
of certain motor-operated hydraulic shutoff valves to detect 
malfunctioning; replacement with new valves, if necessary; and eventual 
replacement of certain existing valves with new valves, which 
terminates the repetitive inspections.

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 concurred with the original notice of proposed 
rulemaking (NPRM), and that commenter submitted no additional comment 
to the supplemental NPRM.

Request To Clarify Subject Valves

    Several commenters request that the FAA clarify the language in the 
original NPRM and supplemental NPRM to clarify what valves on the 
airplane are subject to the proposed AD. The commenters point out that 
the referenced service bulletins apply only to valves in ``sensitive 
system'' applications (hereinafter referred to as ``sensitive'' 
applications). However, the language in the NPRM and supplemental NPRM 
does not clarify whether only valves with the subject part numbers (P/
N) in ``sensitive'' applications are subject to the requirements of the 
proposed AD, or whether ALL valves with the subject P/N's installed on 
the airplane are subject to the proposed AD, regardless of whether the 
valves are installed in ``sensitive'' or ``non-sensitive'' 
applications.
    The FAA concurs with the commenters' request for clarification. 
This AD is intended to apply only to the valves in locations listed in 
the referenced service bulletins--that is, valves in ``sensitive'' 
applications. The FAA has revised paragraphs (a) and (b) of this AD 
accordingly and added a new note, Note 1, after the applicability 
statement to clarify this issue. (Subsequent notes have also been 
reordered.)
    Operators should note that, while the airplane manufacturer will 
issue new service bulletins with instructions for

[[Page 31136]]

replacing valves in ``non-sensitive'' applications on the affected 
airplanes, at this time, the FAA does not plan to mandate replacing 
these valves.

Request To Reference New Service Information

    Several operators request that the FAA revise the proposed AD to 
reference new service bulletins issued by Boeing.
    The FAA concurs with the commenters' request and--since the 
issuance of the supplemental NPRM--has reviewed and approved the 
following 10 new service bulletins:
    <bullet> Boeing Alert Service Bulletin 737-29A1073, Revision 3, 
including Appendices A and B, dated December 2, 1999: This service 
bulletin revises Boeing Service Bulletin 737-29A1073, Revision 2, dated 
July 1, 1999, which was referenced as an appropriate source of service 
information in the supplemental NPRM. Revision 3 describes procedures 
for repetitive operational checks of certain motor-operated hydraulic 
shutoff valves to detect malfunctioning on certain Boeing Model 737-
100, -200, -300, -400, and -500 series airplanes. The procedures in 
this bulletin are essentially similar to those in Revision 2; however, 
this service bulletin removes all Boeing Model 737-600, 737-700, and 
737-800 series airplanes from the effectivity listing. (Boeing Model 
737-600, -700, and -800 series airplanes have been included in a new 
service bulletin, which is described below.) This service bulletin also 
references a new service bulletin, described below, that describes 
replacement of the subject valves with new, improved valves, which ends 
the need for the repetitive operational checks.
    <bullet> Boeing Alert Service Bulletin 737-29A1081, including 
Appendices A and B, dated December 2, 1999: This service bulletin 
describes procedures for repetitive operational checks of certain 
motor-operated hydraulic shutoff valves to detect malfunctioning on 
certain Boeing Model 737-600, 737-700, and 737-800 series airplanes. 
These procedures are essentially the same as those described in Boeing 
Alert Service Bulletin 737-29A1073, Revision 2, for these airplanes. 
This service bulletin also references a new service bulletin, described 
below, that describes replacement of the subject valves with new, 
improved valves, which ends the need for the repetitive operational 
checks.
    <bullet> Boeing Alert Service Bulletin 757-29A0048, Revision 3, 
including Appendices A and B, dated December 2, 1999: This service 
bulletin revises Boeing Service Bulletin 757-29A0048, Revision 2, dated 
July 1, 1999, which was referenced as an appropriate source of service 
information in the supplemental NPRM. Revision 3 describes procedures 
for repetitive operational checks of certain motor-operated hydraulic 
shutoff valves to detect malfunctioning on certain Boeing Model 757 
series airplanes. The procedures in this service bulletin are 
essentially similar to those in Revision 2; however, this service 
bulletin removes all Boeing Model 757-300 series airplanes from the 
effectivity listing. (Boeing Model 757-300 series airplanes have been 
included in a new service bulletin, which is described below.) This 
service bulletin also references a new service bulletin, described 
below, that describes replacement of the subject valves with new, 
improved valves, which ends the need for the repetitive operational 
checks.
    <bullet> Boeing Alert Service Bulletin 757-29A0051, including 
Appendices A and B, dated December 2, 1999: This service bulletin 
describes procedures for repetitive operational checks of certain 
motor-operated hydraulic shutoff valves to detect malfunctioning on 
certain Boeing Model 757-300 series airplanes. These procedures are 
essentially similar to those described in Boeing Alert Service Bulletin 
757-29A0048, Revision 2, for these airplanes. This service bulletin 
also references a new service bulletin, described below, that describes 
replacement of the subject valves with new, improved valves, which ends 
the need for the repetitive operational checks.
    <bullet> Boeing Service Bulletin 767-29A0083, Revision 4, including 
Appendix A, dated September 28, 2000: This service bulletin revises 
Boeing Service Bulletin 767-29A0083, Revision 2, dated July 15, 1999, 
which was referenced as an appropriate source of service information in 
the supplemental NPRM. This service bulletin describes procedures for 
repetitive operational checks of certain motor-operated hydraulic 
shutoff valves to detect malfunctioning on certain Boeing Model 767 
series airplanes. The procedures in this service bulletin are 
essentially similar to those in Revision 2. However, this service 
bulletin also corrects certain instructions for the functional test of 
two of the motor-operated hydraulic shutoff valves. The service 
bulletin states that the functional tests in previous revisions of the 
service bulletin, including Revision 2, could not be completed without 
the revised instructions contained in Revision 4.
    <bullet> Boeing Alert Service Bulletin 737-29A1078, dated December 
7, 2000: This service bulletin describes procedures for replacement of 
Circle Seal Controls valves in ``sensitive'' applications on certain 
Boeing Model 737-100, -200, -300, -400, and -500 series airplanes, with 
certain new Whittaker Controls valves or new, improved Circle Seal 
Controls valves. Such replacement terminates the repetitive operational 
checks described in Boeing Alert Service Bulletin 737-29A1073, Revision 
3.
    <bullet> Boeing Alert Service Bulletin 737-29A1082, dated December 
7, 2000: This service bulletin describes procedures for replacement of 
Circle Seal Controls valves in ``sensitive'' applications on certain 
Boeing Model 737-600, -700, and -800 series airplanes, with certain new 
Whittaker Controls valves or new, improved Circle Seal Controls valves. 
Such replacement terminates the repetitive operational checks described 
in Boeing Alert Service Bulletin 737-29A1081.
    <bullet> Boeing Alert Service Bulletin 757-29A0049, dated December 
7, 2000: This service bulletin describes procedures for replacement of 
Circle Seal Controls valves in ``sensitive'' applications on certain 
Boeing Model 757-200 series airplanes, with certain new Whittaker 
Controls valves or new, improved Circle Seal Controls valves. Such 
replacement terminates the repetitive operational checks described in 
Boeing Alert Service Bulletin 757-29A0048, Revision 3.
    <bullet> Boeing Alert Service Bulletin 757-29A0052, dated December 
7, 2000: This service bulletin describes procedures for replacement of 
Circle Seal Controls valves in ``sensitive'' applications on certain 
Boeing Model 757-300 series airplanes, with certain new Whittaker 
Controls valves or new, improved Circle Seal Controls valves. Such 
replacement terminates the repetitive operational checks described in 
Boeing Alert Service Bulletin 757-29A0051.
    <bullet> Boeing Alert Service Bulletin 767-29A0090, dated December 
7, 2000: This service bulletin describes procedures for replacement of 
Circle Seal Controls valves in ``sensitive'' applications on certain 
Boeing Model 767 series airplanes, with certain new Whittaker Controls 
valves or new, improved Circle Seal Controls valves. Such replacement 
terminates the repetitive operational checks described in Boeing 
Service Bulletin 767-29A0083, Revision 4.
    In view of the approval of these service bulletins by the FAA, we 
have revised paragraph (a) of this AD to specify Boeing Service 
Bulletins 737-29A1073, Revision 3 (for Model 737-

[[Page 31137]]

100, -200, -300, -400, and -500 series airplanes), 737-29A1081 (for 
Model 737-600, -700, and ``800 series airplanes), 757-29A0048, Revision 
3 (for Model 757-200 series airplanes), 757-29A0051 (for Model 757-300 
series airplanes), and 767-29A0083, Revision 4 (for Model 767 series 
airplanes); as applicable; as appropriate sources of service 
information for the requirements of that paragraph. The FAA has revised 
paragraph (b) of this AD to specify Boeing Alert Service Bulletins 737-
29A1078 (for Model 737-100, -200, -300, -400, and -500 series 
airplanes), 737-29A1082 (for Model 737-600, -700, and -800 series 
airplanes), 757-29A0049 (for Model 757-200 series airplanes), 757-
29A0052 (for Model 757-300 series airplanes), and 767-29A0090 (for 
Model 767 series airplanes), as appropriate sources of service 
information for the requirements of that paragraph.
    In addition, the FAA has provided for airplanes on which the 
requirements of this AD have been accomplished before the effective 
date of this AD, by adding two new notes, Notes 3 and 4, which specify 
that operational checks and valve replacements done before the 
effective date of this AD per Boeing Alert Service Bulletins 737-
29A1073, Revision 2, or 757-29A0048, Revision 2, both dated July 1, 
1999; or 767-29A0083, Revision 2, dated July 15, 1999; as applicable; 
are acceptable for compliance with paragraphs (a) and (b) of this AD.
    Also, the applicability statement of this final rule has been 
revised to specify airplanes listed in Boeing Service Bulletins 737-
29A1073, Revision 3, 737-29A1081, 757-29A0048, Revision 3, 757-29A0051, 
and 767-29A0083, Revision 4. The FAA has determined that this change 
does not add any new airplanes to the applicability statement which 
were not included in the applicability statement of the proposed rule.

Allow Use of Serviceable Parts

    Several commenters request that the FAA revise paragraph (a)(1) of 
the supplemental NPRM to allow replacement of malfunctioning Circle 
Seal Controls valves having P/N's S270T010-1 through -9, with new or 
serviceable Circle Seal Controls valves having P/N's S270T010-1 through 
-9. Paragraph (a)(1) of the supplemental NPRM requires replacement of a 
malfunctioning valve with a new Whittaker Controls valve, and paragraph 
(c) of the supplemental NPRM prohibits installation after the effective 
date of this AD of ``any part identified in the `Existing Part Number' 
column (including parts marked with the suffix ``R'' after the serial 
number), of Paragraph 2.E.'' of the applicable alert service bulletin. 
Parts listed in the ``Existing Part Number'' column are Circle Seal 
Controls valves having P/N's S270T010-1 through -9. The commenters 
state that prohibiting installation any new or serviceable valves with 
P/N's S270T010-1 through -9 imposes an undue burden on operators. 
Commenters are also concerned that airplanes needing replacement valves 
could be grounded if Whittaker Controls is unable to produce a 
sufficient amount of replacement parts.
    The FAA concurs with the commenters' request to allow installation 
of serviceable parts. The FAA has revised paragraph (a)(2) of this AD 
to allow replacement of a malfunctioning valve with a new or 
serviceable replacement valve manufactured by Circle Seal Controls or 
Whittaker Controls. A valve replaced with a new or serviceable Circle 
Seal Controls valve having a P/N S270T010-1 through -9 will continue to 
be subject to repetitive operational checks per paragraph (a) of this 
AD, until the terminating action is accomplished per paragraph (b). 
Replacement of a valve with a new or serviceable Whittaker Controls 
valve or a new or serviceable Circle Seal Controls valve with P/N 
S270T010-10, -11, -12, -13, -14, or -15; as applicable; terminates the 
repetitive inspections for the replaced valve. Relevant to this change 
to paragraph (a)(1) of this AD, it is no longer necessary to include 
paragraph (c) of the supplemental NPRM in this AD. [Installation of a 
Circle Seal Controls valve having a P/N S270T010-1 through -9 is 
prohibited after 3 years after the effective date of this AD by virtue 
of the terminating action required by paragraph (b) of this AD.]

Request To Clarify Need for Repetitive Operational Checks

    Two commenters request that the FAA clarify the requirements of 
paragraph (a)(1) of the supplemental NPRM. The commenters point out 
that paragraph (a)(1) of the supplemental NPRM requires replacement of 
any malfunctioning Circle Seal Controls valve with a new Whittaker 
Controls valve before further flight. However, that paragraph goes on 
to require repeating the operational check required by paragraph (a). 
The commenters point out that paragraph (b) of the supplemental NPRM 
states that replacement of Circle Seal Controls valves with new 
Whittaker Controls valves constitutes terminating action for the 
repetitive inspections required by paragraph (a) of this AD. Therefore, 
replacement parts installed per paragraph (a)(1) of this AD should not 
be subject to the repetitive operational checks.
    The FAA concurs with the commenters' rationale. Replacement of all 
existing Circle Seal Controls valves with new Whittaker Controls valves 
does constitute terminating action for the requirements of paragraph 
(a) of this AD for the replaced valve. However, as stated previously, 
the FAA has revised this final rule to allow replacement of existing 
Circle Seal Controls valves with serviceable valves having certain part 
numbers. Accordingly, paragraph (a)(1) has been revised in this final 
rule, and paragraph (c) of the supplemental NPRM has not been included 
in this final rule. No further change to the final rule is needed in 
this regard.

Request To Allow Use of Certain Other Valves for Terminating Action

    Several commenters request that the FAA revise the supplemental 
NPRM to allow use of certain valves manufactured by Circle Seal 
Controls, Inc., as terminating action for the repetitive operational 
checks in paragraph (a) of the proposed AD. The supplemental NPRM only 
allowed replacement of any Circle Seal Controls valve with a new 
Whittaker Controls valve as terminating action for the repetitive 
operational checks. (The original NPRM had referenced replacement with 
Circle Seal Controls valves with part numbers (P/N) S270T010-10, -11, 
and -12, as terminating action. However, as explained in the 
supplemental NPRM, the FAA reviewed information regarding the failure 
rate of the valves and determined that the valves were not an adequate 
replacement.) The commenters' rationale for their requests includes the 
following:
    <bullet> Boeing has found that initial failures of Circle Seal 
Controls valves with P/N's S270T010-10, -11, and -12 were due to 
improper rework rather than design flaws. Thus, Boeing now considers 
these Circle Seal Controls valves adequate for terminating action. 
Other commenters state that these Circle Seal Controls valves provide 
an equivalent level of safety to that provided by the Whittaker 
Controls valves.
    <bullet> Some operators are concerned about Whittaker Controls' 
ability to produce an adequate supply of replacement parts within the 
three-year compliance time for the replacement required by this AD.
    <bullet> Some operators point out that the supplemental NPRM does 
not require

[[Page 31138]]

repetitive operational checks of Circle Seal Controls valves with P/N's 
S270T010-10, -11, and -12; therefore, these valves should be acceptable 
for terminating action.
    The FAA concurs with the commenters' request to revise the final 
rule to allow use of certain Circle Seal Controls valves as terminating 
action for this AD's repetitive operational checks. The FAA finds that 
replacement of existing Circle Seal Controls valves with Circle Seal 
Controls valves with P/N S270T010-10, -11, -12, -13, -14, or -15; or 
with Whittaker Controls valves; is acceptable for doing the terminating 
action in paragraph (b) of this AD. Paragraph (b) of this AD has been 
revised accordingly.
    While replacement with Circle Seal Controls valves with P/Ns 
S270T010-10, -11, and -12 is acceptable as terminating action, the FAA 
points out that these valves are not currently being manufactured by 
Circle Seal Controls. That company is only manufacturing P/Ns S270T010-
13, -14, and -15 valves.

Request To Revise Preamble Language

    One commenter requests that the FAA revise the ``Discussion'' 
section in the original NPRM and one sentence in the ``Summary'' 
section to more accurately explain what prompted the proposed AD. The 
sentence in the ``Summary'' explains that the proposal ``was prompted 
by reports that the motor switch contacts on certain hydraulic shutoff 
valves were mis-aligned, causing subsequent malfunction of those 
valves.'' The commenter states that this statement could be misleading 
and requests that the FAA use a more general statement.
    The FAA concurs with the commenter's request, and has revised the 
affected sentence in the summary of this final rule to state that this 
AD is prompted by reports that ``various intermittent limit switch 
problems have caused valve failures.'' (As the ``Discussion'' section 
is not restated in this final rule, no change is necessary in that 
regard.)

Request To Allow Installation of Only Certain Valves

    One commenter requests that the FAA NOT revise the supplemental 
NPRM to allow installation of Circle Seal Controls valves to be 
terminating action for the repetitive operational checks in this AD. 
The commenter states that Circle Seal Controls, Inc., has repeatedly 
failed to design and manufacture reliable valves. The commenter points 
out that each new design has met all of the airplane manufacturer's 
design criteria, passed all the appropriate tests, and been approved by 
the FAA. However, after each approval, the valves failed to function. 
The commenter also questions whether the FAA made an error in the 
applicability of the supplemental NPRM by making the AD apply only to 
Circle Seal Controls valves having P/N S270T010-1 through -9. The 
commenter requests that the AD also apply to Circle Seal Controls 
valves having P/N S270T010-10 through -12.
    The FAA does not concur with the commenter's requests. Information 
provided by the manufacturer regarding the failure rate of Circle Seal 
Controls valves having P/N S270T010-10 through -12 resulted in the FAA 
removing these parts from the list of replacement parts acceptable for 
terminating action in the supplemental NPRM. However, since the 
issuance of the supplemental NPRM, the FAA has determined that the 
failures in Circle Seal Controls valves having P/N S270T010-10 through 
-12 were due to manufacturing errors, not design flaws. Also, further 
refinements in the design of P/N S270T010-13 through -15 have focused 
on improving the ease of manufacture and assembly of the valves. Thus, 
as stated previously, the FAA is revising this final rule to allow 
installation of either new Whittaker Controls valves or new Circle Seal 
Controls parts having P/N S270T010-10 through -15 as terminating action 
for the requirements of this AD. The FAA finds that these parts will 
adequately ensure the continued safety of the airplane fleet. No 
further change to the final rule is necessary in this regard.

Request To Require Replacement of All Valves in All Locations

    One of the commenters that requested clarification on which valves 
are subject to the proposed AD also requests that the FAA require 
replacement of ALL valves of the subject part numbers on the affected 
airplanes, not just those installed in locations listed in the service 
bulletins. The commenter's rationale is that, if the AD applies only to 
valves installed in ``sensitive'' applications, it will result in a 
``configuration control nightmare'' for operators, with some valves 
being acceptable for installation in some applications on the affected 
airplanes, but not in other applications. The commenter's point is that 
valves may not be interchangeable from one location to another. Thus, 
operators will be forced to track the manufacturer of every valve and 
create customized maintenance instructions to ensure that correct 
valves are installed in the correct locations on the airplane.
    Though the FAA acknowledges that operators will have to track the 
location of each valve to ensure that only the correct parts are 
installed in the locations identified in the referenced service 
bulletins, the FAA does not concur that it is necessary to require 
replacement of all valves of the affected part numbers, regardless of 
location, on the subject airplanes. Requiring replacement of all valves 
in all locations, ``sensitive'' and ``non-sensitive,'' would place an 
undue burden on affected operators and may call into question the 
availability of replacement parts for the three-year compliance time. 
No change to the final rule is necessary in this regard.

Request To Extend Threshold/Repetitive Interval for Operational 
Checks

    Two commenters request that the FAA increase the threshold and 
repetitive interval for the operational checks in paragraph (a) of the 
proposed AD. One commenter requests that the interval be increased from 
6 months to 456 days; the other commenter requests an increase to 1 
year. The first commenter states that the frequency of operational 
checks associated with the six-month interval may increase the 
likelihood of failure of the valves. The commenter bases its comment on 
the fact that, except for testing, the valves would normally only be 
operated during an emergency situation, and the six-month interval 
would add unnecessary cycles and may eventually contribute to an early 
failure of the valves. The other commenter states that there is no 
technical justification for the six-month threshold and interval 
because proper operation of the valves cannot be guaranteed no matter 
how frequent the operational checks. The commenters both state that an 
increased threshold and repetitive interval will still be adequate to 
ensure safety of flight.
    The FAA does not concur with the commenters' requests. While the 
second commenter is correct that an operational check only guarantees 
the functionality of the valve for that one cycle and the valve could 
fail the next time it is cycled, the FAA finds that the operational 
check may be sufficient to detect valves that are likely to fail. In 
addition, the repetitive inspection interval of six months will ensure 
that a failed valve will be detected in a timely manner. No change to 
the final rule is necessary in this regard.

Request To Extend Compliance Time for Replacement

    Several commenters request that the FAA revise the proposed rule to 
extend

[[Page 31139]]

the three-year compliance time for the replacement in paragraph (b) of 
the proposed AD. Certain commenters state that three years is not 
enough time for operators to replace nearly 5,000 valves in the 
affected airplane fleet. One commenter suggests a compliance time of 
four years; another suggests four and a half years. Certain commenters 
express concern that the parts manufacturers may not be able to produce 
an adequate supply of parts for replacement of affected valves on the 
entire affected worldwide fleet within the three-year compliance time. 
The commenters state that repetitive operational checks at six-month 
intervals, as required by paragraph (a) of this AD, should provide an 
adequate level of safety until valves can be replaced.
    The FAA does not concur with the commenters' request for an 
extension of the compliance time for paragraph (b) of this AD. The 
compliance time for the replacement of existing Circle Seal Controls 
valves was extended from two years to three years in the supplemental 
NPRM. The FAA finds that three years is the maximum time that affected 
airplanes may be allowed to continue to operate with the older-design 
Circle Seal Controls valves installed. Based on commitments by 
Whittaker Controls, the FAA finds that an adequate supply of 
replacement parts will be available within the three-year compliance 
time for replacement the subject valves on affected airplanes. No 
change to the final rule is necessary in this regard.

Request To Revise Cost Estimate

    Two commenters ask the FAA to revise the cost impact information 
presented in the proposed rule. One of the commenters states that, for 
the operational check on Model 757 series airplanes, it finds 12 work 
hours to be a more accurate estimate than the 3 hours stated in the 
proposal. The other commenter states that the FAA has ``grossly 
underestimated'' the costs associated with this AD: the estimated 
inspection cost is for a single operational check, but the check will 
be required twice per year until accomplishment of the terminating 
action. The second commenter also states that if the cost estimate is 
intended to reflect the cost of replacing all Circle Seal Controls 
valves (i.e., in ``sensitive'' and ``non-sensitive'' applications), the 
FAA's underestimation is worse.
    The FAA does not concur with the commenters' request to revise the 
cost impact information. The cost impact information describes only the 
``direct'' costs of the specific actions required by this AD. The 
number of work hours necessary to accomplish the required actions is 
based on the manufacturer's estimate provided in the service bulletin, 
excluding the time necessary to gain access and close up. The estimate 
represents the time necessary to perform only the actions actually 
required by this AD. The FAA recognizes that, in accomplishing the 
requirements of any AD, operators may incur ``incidental'' costs in 
addition to the ``direct'' costs. 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.
    With regard to the commenter's observation that the cost impact 
estimate is only for a single operational check, the FAA points out 
that the cost estimate states that the cost is ``per operational 
check.''
    With regard to the commenter's observation about replacement of all 
Circle Seal Controls valves versus replacement of all valves specified 
in the service bulletin: as stated previously, this AD only requires 
replacement of the valves stated in the applicable service bulletin.
    No change to the final rule is necessary 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 3,029 Boeing Model 737 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 
1,234 airplanes of U.S. registry will be affected by this AD, and that 
it will take approximately 2 work hours per airplane to accomplish the 
required operational check, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of this requirement on 
U.S. operators of these airplanes is estimated to be $148,080, or $120 
per airplane, per operational check.
    There are approximately 802 Boeing Model 757 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 558 
airplanes of U.S. registry will be affected by this AD, and that it 
will take approximately 3 work hours per airplane to accomplish the 
required operational check, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of this requirement on 
U.S. operators of these airplanes is estimated to be $100,440, or $180 
per airplane, per operational check.
    There are approximately 701 Boeing Model 767 series airplanes of 
the affected design in the worldwide fleet. The FAA estimates that 280 
airplanes of U.S. registry will be affected by this AD, and that it 
will take approximately 4 work hours per airplane to accomplish the 
required operational check, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of this requirement on 
U.S. operators of these airplanes is estimated to be $67,200, or $240 
per airplane, per operational check.
    For all airplanes, it will take approximately 5 work hours per 
valve to accomplish the replacement required by this AD, at an average 
labor rate of $60 per work hour. Required parts and hydraulic fluid 
will cost approximately $4,316 per airplane. Based on these figures, 
the cost impact of the valve replacements required by this AD on U.S. 
operators is estimated to be $4,616 per airplane, per valve 
replacement. This AD will require eventual replacement of approximately 
5,000 valves.
    The cost impact figures discussed above are 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. 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

[[Page 31140]]

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:

2001-11-07 Boeing: Amendment 39-12249. Docket 98-NM-298-AD.

    Applicability: Model 737, 757, and 767 series airplanes, 
certificated in any category, as listed in the following Boeing 
Service Bulletins:

                          Table 1.--Effectivity
------------------------------------------------------------------------
                                                      Affected models/
    Boeing Service Bulletin            Date                series
------------------------------------------------------------------------
737-29A1073, Revision 3.......  December 2, 1999.  Model 737-100, -200,
                                                    300, -400, and -500.
737-29A1081...................  December 2, 1999.  Model 737-600, -700,
                                                    and -800.
757-29A0048, Revision 3.......  December 2, 1999.  Model 757-200.
757-29A0051...................  December 2, 1999.  Model 757-300.
767-29A0083, Revision 4.......  September 28,      Model 767.
                                 2000.
------------------------------------------------------------------------


    Note 1: Only motor operated hydraulic shutoff valves 
manufactured by Circle Seal Controls that are installed in the 
locations specified in the applicable alert service bulletin listed 
in the table above are subject to 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 failure of the motor operated hydraulic shutoff 
valves, which could result in leakage of hydraulic fluid to the 
engine fire zone, reduced ability to retract the landing gear, loss 
of backup electrical power or other combinations of failures, and 
consequent reduced controllability of the airplane, accomplish the 
following:

Repetitive Operational Checks/Corrective Action

    (a) Within 6 months after the effective date of this AD: Perform 
an operational check to detect malfunctioning of any Circle Seal 
Controls motor operated hydraulic shutoff valve in a ``sensitive 
system'' application (as defined in the applicable service bulletin) 
having a part number specified in the ``Existing Part Number'' 
column (including parts marked with the suffix ``R'' after the 
serial number), of Paragraph 2.E. of Boeing Alert Service Bulletins 
737-29A1073, Revision 3 (for Model 737-100, -200, -300, -400, and -
500 series airplanes), 737-29A1081 (for Model 737-600, -700, and -
800 series airplanes), 757-29A0048, Revision 3 (for Model 757-200 
series airplanes), or 757-29A0051 (for Model 757-300 series 
airplanes); all dated December 2, 1999; or Boeing Service Bulletin 
767-29A0083, Revision 4, dated September 28, 2000 (for Model 767 
series airplanes); as applicable; in accordance with the applicable 
service bulletin.
    (1) If any malfunction of any valve is detected, prior to 
further flight, replace the valve with a new or serviceable 
Whittaker Controls or Circle Seal Controls valve in accordance with 
the applicable service bulletin. Repeat the operational check 
thereafter at intervals not to exceed 6 months until accomplishment 
of the terminating action required by paragraph (b) of this AD on 
all subject valves.
    (2) If no malfunction of any valve is detected, repeat the 
operational check thereafter at intervals not to exceed 6 months 
until accomplishment of the terminating action required by paragraph 
(b) of this AD on all subject valves.

    Note 3: Operational checks done before the effective date of 
this AD per Boeing Alert Service Bulletin 737-29A1073, Revision 2 
(for Model 737 series airplanes), or 757-29A0048, Revision 2 (for 
Model 757 series airplanes), both dated July 1, 1999; or 767-
29A0083, Revision 2, dated July 15, 1999 (for Model 767 series 
airplanes); as applicable; is acceptable for compliance with 
paragraph (a) of this AD.

Terminating Action

    (b) Within 3 years after the effective date of this AD, 
accomplish the replacement of any Circle Seal Controls valve in a 
``sensitive system'' application (as defined in the applicable 
service bulletin) having a P/N specified in the ``Existing Part 
Number'' column (including parts marked with the suffix ``R'' after 
the serial number), of Paragraph 2.E. of Boeing Alert Service 
Bulletin 737-29A1078 (for Model 737-100, -200, -300, -400, and -500 
series airplanes), 737-29A1082 (for Model 737-600, -700, and -800 
series airplanes), 757-29A0049 (for Model 757-200 series airplanes), 
757-29A0052 (for Model 757-300 series airplanes), or 767-29A0090 
(for Model 767 series airplanes); all dated December 7, 2000; as 
applicable. Replace an existing part with a new Whittaker Controls 
valve having a P/N specified in the ``New Part Number'' column of 
Paragraph 2.E. of the applicable service bulletin; or with a new 
Circle Seal Controls valve having P/N S270T010-10, -11, -12, -13, -
14, or -15; as applicable. Do the replacement in accordance with the 
applicable alert service bulletin. Accomplishment of this 
replacement constitutes terminating action for the repetitive 
operational checks required by this AD.

    Note 4: Replacement of Circle Seal Controls valves done before 
the effective date of this AD per Boeing Alert Service Bulletin 737-
29A1073, Revision 2 (for Model 737 series airplanes), or 757-
29A0048, Revision 2 (for Model 757 series airplanes), both dated 
July 1, 1999; or 767-29A0083, Revision 2, dated July 15, 1999 (for 
Model 767 series airplanes); as applicable; is acceptable for 
compliance with paragraph (b) of this AD.


[[Page 31141]]



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 5: 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 Alert 
Service Bulletin 737-29A1073, Revision 3, dated December 2, 1999; 
Boeing Alert Service Bulletin 737-29A1081, dated December 2, 1999: 
Boeing Alert Service Bulletin 757-29A0048, Revision 3, dated 
December 2, 1999; Boeing Alert Service Bulletin 757-29A0051, dated 
December 2, 1999; Boeing Service Bulletin 767-29A0083, Revision 4, 
dated September 28, 2000; Boeing Alert Service Bulletin 737-29A1078, 
dated December 7, 2000; Boeing Alert Service Bulletin 737-29A1082, 
dated December 7, 2000; Boeing Alert Service Bulletin 757-29A0049, 
dated December 7, 2000; Boeing Alert Service Bulletin 757-29A0052, 
dated December 7, 2000; or Boeing Alert Service Bulletin 767-
29A0090, dated December 7, 2000; 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.

Effective Date

    (f) This amendment becomes effective on July 16, 2001.

    Issued in Renton, Washington, on May 25, 2001.
Vi L. Lipski,
Manager, Transport Airplane Directorate,Aircraft Certification Service.
[FR Doc. 01-14000 Filed 6-8-01; 8:45 am]
BILLING CODE 4910-13-U