[Federal Register Volume 65, Number 120 (Wednesday, June 21, 2000)]
[Proposed Rules]
[Pages 38450-38453]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-15661]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-298-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Supplemental notice of proposed rulemaking; reopening of 
comment period.

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SUMMARY: This document revises an earlier proposed airworthiness 
directive (AD), applicable to certain Boeing Model 737, 757, and 767 
series airplanes, that would have required repetitive inspections of 
certain motor operated hydraulic shutoff valves to detect 
malfunctioning; and replacement with new valves, if necessary. That 
proposal also would have required eventual replacement of certain 
existing valves with new valves, which would have constituted 
terminating action for the repetitive inspections. That proposal was 
prompted by reports that the motor switch contacts on certain hydraulic 
shutoff valves were misaligned, causing subsequent malfunction of those 
valves. This new action revises the proposed rule by extending a 
certain compliance

[[Page 38451]]

time and revising certain actions. The actions specified by this new 
proposed 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: Comments must be received by July 17, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 98-NM-298-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Kenneth W. Frey, 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) 227-2673; fax (425) 
227-1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 98-NM-298-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 98-NM-298-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    A proposal to amend part 39 of the Federal Aviation Regulations (14 
CFR part 39) to add an airworthiness directive (AD), applicable to 
certain Boeing Model 737, 757, and 767 series airplanes, was published 
as a notice of proposed rulemaking (NPRM) in the Federal Register on 
October 27, 1999 (64 FR 57808). That NPRM would have required 
repetitive inspections of certain motor operated hydraulic shutoff 
valves to detect malfunctioning; and replacement with new valves, if 
necessary. That NPRM also would have required eventual replacement of 
certain existing valves with new valves, which would have constituted 
terminating action for the repetitive inspections. That NPRM was 
prompted by reports that the motor switch contacts on certain hydraulic 
shutoff valves were misaligned, causing subsequent malfunction of those 
valves. That condition, if not corrected, could result in failure of 
the motor operated hydraulic shutoff valves, subsequent 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.

Comments Received to Previous Proposal

    Due consideration has been given to the comments received in 
response to the NPRM:

Request To Revise Inspection Category Described in the Proposed 
Rule

    Several commenters request that the phrase ``general visual 
inspection'' be changed to ``operational check.'' One commenter states 
that it defines a general visual inspection as a static inspection, and 
the inspections described in the alert service bulletins are dynamic 
inspections and require verification that certain criteria are met 
during operation of the valves. Another commenter states that the term 
``visual inspection'' is misleading, as the valve failures can be 
identified only by the operational checks identified in the alert 
service bulletins; additionally, two commenters state that the 
bulletins do not describe a general visual inspection and, in fact, 
contain instructions for detailed operational checks. Yet another 
commenter suggests the instructions for a general visual inspection be 
expanded in order to clarify what needs to be inspected.
    The FAA concurs with the commenters' requests to change the phrase 
``general visual inspection'' to ``operational check.'' The alert 
service bulletins describe instructions for detailed operational checks 
of the motor operated shutoff valves; however, there is no general 
visual inspection specified in the bulletins. Therefore, paragraph (a) 
of the supplemental NPRM (SNPRM) has been revised to specify 
accomplishment of an operational check in lieu of a general visual 
inspection. In addition, `NOTE 2' of the NRPM, which describes a 
general visual inspection, has been removed.

Request for Extension of Compliance Time

    Several commenters request that the FAA extend the proposed 
compliance time for the replacement of the valves as specified in 
paragraph (b) of the proposed rule. One commenter states that fleet 
safety would not be adversely impacted if the compliance time for the 
proposed terminating action were extended to a proposed four years. The 
commenter's reasons for this statement are the calculated mean time 
between valve failures, in combination with an unlikely event that 
creates the need for only one of the valves to operate; and the 
operational checks accomplished in the interim. The commenter has been 
working with the valve supplier and the airlines to create a fleet 
retrofit program and notes that it does not consider it possible to 
complete the retrofit of the affected airplanes in less than four 
years. Another commenter requests a minimum of six years to complete 
the replacement of all the valves due to the large number of valves 
involved. Another commenter states that there is concern that the parts 
suppliers will not be able to supply sufficient ``seed'' units at a 
turn around time adequate to support a two-year retrofit program. 
Another commenter contends that the data should be analyzed prior to 
mandating a valve replacement period and requests that the two-year

[[Page 38452]]

mandatory replacement be deleted from the proposal. The commenter 
remarks that the present six-month repetitive operational check 
interval will provide an acceptable level of safety until such time as 
the valves can be retrofitted. Another commenter requests that relief 
be given to allow for installation (replacement) of the valves past the 
effective date of the proposed AD, as long as all units on the airplane 
are inspected at six-month intervals and replaced prior to the proposed 
compliance time. Yet another commenter states that two years is a short 
compliance time, considering that a very large number of airplanes 
(over 2,000) with five or more Circle Seal control valves installed 
that need to be retrofitted. The commenter doubts that this is a 
realistic proposal and would like to have an extension of the 
compliance date, in addition to split compliance times for the valves 
used in sensitive and non-sensitive applications, which would reduce 
the number of valves that need to be replaced urgently. The last 
commenter states that the manufacturer is scheduled to release new 
service bulletins that detail the replacement of the valves used in 
sensitive and non-sensitive applications.
    The FAA concurs partially with the commenters' requests/
suggestions. Following careful consideration of all the comments, the 
FAA agrees to an extension of the compliance time for replacement of 
the valves to three years, due to the large number of valves involved, 
and in order to allow operators to obtain the necessary parts based on 
supplier ability to produce the parts within that timeframe. However, 
the FAA has determined that three years is the maximum amount of time 
allowable for this extension so that it will not adversely affect fleet 
safety, in that data received from the manufacturer shows that a longer 
extension could result in the risk of failure of a defective valve 
through normal operation of opening and closing repeatedly. Due to this 
risk, the six-month repetitive operational check interval, to ensure 
the valve is operating and the valve motor has not burned up due to 
repetitive operation, will provide an acceptable level of safety until 
such time as the valves can be retrofitted. Therefore, paragraph (b) of 
the SNPRM has been revised accordingly.

Request To Delete or Revise Paragraph (b)(2) of the Proposed Rule

    Several commenters request that paragraph (b)(2) of the proposal be 
either deleted or revised. One commenter states that based on past 
performance, there is a high probability that installation of the 
fourth generation Circle Seal valves will not adequately address the 
identified unsafe condition. The commenter requests that the option to 
replace the existing valves with new Circle Seal valves, as specified 
in paragraph (b)(2) of the proposed AD, be deleted. Another commenter 
states that paragraph (b)(2) should apply only to those valves 
identified in the alert service bulletins referenced in the proposal. 
The commenter notes that the words in this paragraph could apply to a 
valve installed in another location on the airplane where failures do 
not have a negative impact on safety. Another commenter requests that 
the requirement to replace the valves be postponed until the problems 
being experienced with the valves are completely resolved. Yet another 
commenter would like to have the option of replacing a defective valve 
with either a Whittaker or a Circle Seal valve, independent of the part 
number used.
    The FAA concurs partially with the commenters' requests. The FAA 
has reviewed information provided by the manufacturer regarding the 
failure rate of the valves. Based on this information, the FAA has 
determined that the valves are not an adequate replacement, in addition 
to difficulty in the installation and operational testing of the 
valves, resulting in failure of numerous valves; therefore, paragraph 
(a)(1) of the SNPRM has been revised to remove all references to 
replacement with Circle Seal valves, and paragraph (b)(2) of the NPRM 
has been deleted. However, the replacement of the existing valves with 
Whittaker valves required by paragraph (b)(1) of the NPRM will remain 
in the AD, and has been moved to paragraph (b) of the SNPRM.

Conclusion

    Since these changes expand the scope of the originally proposed 
rule, the FAA has determined that it is necessary to reopen the comment 
period to provide additional opportunity for public comment.

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 would be affected by this proposed AD, 
and that it would take approximately 2 work hours per airplane to 
accomplish the proposed operational check, at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of the 
proposed AD on U.S. operators 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 would be affected by this proposed AD, and 
that it would take approximately 3 work hours per airplane to 
accomplish the proposed operational check, at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of the 
proposed AD on U.S. operators 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 would be affected by this proposed AD, and 
that it would take approximately 4 work hours per airplane to 
accomplish the proposed operational check, at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of the 
proposed AD on U.S. operators is estimated to be $67,200, or $240 per 
airplane, per operational check.
    For all airplanes, it would take approximately 5 work hours per 
valve to accomplish the proposed replacement, at an average labor rate 
of $60 per work hour. Required parts and hydraulic fluid would cost 
approximately $4,316 per airplane. Based on these figures, the cost 
impact of the valve replacements proposed by this AD on U.S. operators 
is estimated to be $4,616 per airplane, per valve replacement. This 
proposed AD would 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 proposed 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 proposed herein would 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 proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if

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promulgated, 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 copy of the draft regulatory 
evaluation prepared for this action is contained in the Rules Docket. A 
copy of it may be obtained by contacting the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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:

Boeing: Docket 98-NM-298-AD.

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

--737-29A1073, Revision 2, dated July 1, 1999 (for Model 737 series 
airplanes);
--757-29A0048, Revision 2, dated July 1, 1999 (for Model 757 series 
airplanes);
--767-29A0083, Revision 2, dated July 15, 1999 (for Model 767 series 
airplanes).

    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 (d) 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 
motor operated hydraulic shutoff valve 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 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; in accordance with the applicable alert service 
bulletin.
    (1) If any malfunction of any valve is detected, prior to 
further flight, replace the valve with a new Whittaker 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.

Terminating Action

    (b) Within 3 years after the effective date of this AD, 
accomplish the replacement of any Circle Seal valve 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 737-29A1073, Revision 2 (for 
Model 737 series airplanes); 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); with a new 
Whittaker valve in accordance with the applicable alert service 
bulletin. Accomplishment of this replacement constitutes terminating 
action for the repetitive operational checks required by this AD.

Spares

    (c) As of the effective date of this AD, no person shall install 
on any airplane, 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 Boeing Alert Service Bulletin 
737-29A1073, Revision 2 (for Model 737 series airplanes); 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.

Alternative Methods of Compliance

    (d) 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

    (e) 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.

    Issued in Renton, Washington, on June 15, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-15661 Filed 6-20-00; 8:45 am]
BILLING CODE 4910-13-U