[Federal Register Volume 68, Number 120 (Monday, June 23, 2003)]
[Proposed Rules]
[Pages 37105-37108]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-15727]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-422-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-100, -200, -200C, -
300, -400, and -500 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 737-100, -200, -
200C, -300, -400, and -500 series airplanes, that would have required 
replacing the existing pressure relief valve on the potable water tank 
with a new, improved pressure relief valve, which is made of stainless 
steel and is non-adjustable. For certain airplanes, that earlier 
proposed AD also would have required modification of certain piping to 
re-locate the pressure relief valve. For certain other airplanes, this 
new action would revise the earlier proposed AD by correcting 
procedures for performing the proposed replacement of the pressure 
relief valve. The actions specified by this new proposed AD are 
intended to prevent rupture of the potable water tank during flight of 
the airplane, which could result in structural damage to the airplane 
and inability to sustain flight loads. This action is intended to 
address the identified unsafe condition.

DATES: Comments must be received by July 18, 2003.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 2000-NM-422-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9 a.m. and 3 p.m., Monday through Friday, except 
Federal holidays. Comments may be submitted via fax to (425) 227-1232. 
Comments may also be sent via the Internet using the following address: 
[email protected]. Comments sent via fax or the Internet must 
contain ``Docket No. 2000-NM-422-AD'' in the subject line and need not 
be submitted in triplicate. Comments sent via the Internet as attached 
electronic files must be formatted in Microsoft Word 97 for Windows or 
ASCII text.
    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: Don Eiford, Aerospace Engineer, ANM-
130S, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056; telephone (425) 917-6465; fax (425) 917-
6590.

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

[[Page 37106]]

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 action may 
be changed in light of the comments received.
    Submit comments using the following format:
    [sbull] Organize comments issue-by-issue. For example, discuss a 
request to change the compliance time and a request to change the 
service bulletin reference as two separate issues.
    [sbull] For each issue, state what specific change to the proposed 
AD is being requested.
    [sbull] Include justification (e.g., reasons or data) for each 
request.
    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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NM-422-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. 2000-NM-422-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 737-100, -200, -200C, -300, -400, and -500 series 
airplanes, was published as a notice of proposed rulemaking (NPRM) in 
the Federal Register on March 18, 2002 (67 FR 11950). That NPRM would 
have required replacing the existing pressure relief valve on the 
potable water tank with a new, improved pressure relief valve, which is 
made of stainless steel and is non-adjustable. For certain airplanes, 
that NPRM also would have required modifying certain piping to replace 
a check valve with a tee, removing the existing pressure relief valve, 
and installing a plug where the existing pressure relief valve was 
located. That NPRM was prompted by reports indicating that there have 
been several occurrences of potable water tanks rupturing while the 
airplane was in flight. That condition, if not corrected, could result 
in structural damage to the airplane and inability to sustain flight 
loads. The purpose of the proposed modification is to relocate the 
pressure relief valve so it is subject to the same air pressure as the 
potable water tank, and therefore will protect the tank from 
overpressurization. Accomplishment of the complete modification per 
Boeing Service Bulletin 737-38-1029 would reinstall the existing 
pressure relief valve in the tee installed per that service bulletin. 
However, this supplemental NPRM would require installation of a new, 
improved relief valve in the tee installed per Boeing Service Bulletin 
737-38-1029 instead of reinstalling the existing pressure relief valve.

Issuance of a New Service Bulletin Revision

    Since the issuance of the earlier NPRM, the FAA has reviewed and 
approved Boeing Service Bulletin 737-38A1047, Revision 2, dated July 
18, 2002. Revision 1 of that service bulletin, dated September 27, 
2001, was referenced in the earlier NPRM as the appropriate service 
information for removing the existing pressure relief valve from the 
potable water tank, and replacing the valve with a new pressure relief 
valve. Revision 2 of that service bulletin was issued to more closely 
align certain airplane effectivity groups with the correct figures in 
the Accomplishment Instructions. Revision 2 of that service bulletin 
describes the procedures in a new Figure 9 for airplanes specified as 
``Group 9,'' and also describes procedures in Figure 5 for airplanes 
specified as ``Group 10.'' Revision 2 of that service bulletin states 
that no more work is necessary if the actions described in the initial 
issuance or Revision 1 of that service bulletin were accomplished. 
Therefore, we have specified that accomplishment of the actions in this 
supplemental NPRM be done per Revision 2 of Boeing Service Bulletin 
737-38A1047.

Comments Received on the Earlier NPRM

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

Request To Prohibit Reinstallation of Certain Parts

    One commenter notes that Boeing Service Bulletin 737-38-1047, 
Revision 1, dated September 27, 2001, is specified as the appropriate 
service information in the earlier NPRM for removing pressure relief 
valves having part number (P/N) 520A-6DB-50 or P/N D524TP6D60 and 
replacing the valves with new pressure relief valves. The commenter 
suggests that the FAA clarify that, after the effective date of the AD, 
installation of pressure relief valves having P/N 520A-6DB-50 or P/N 
D524TP6D60 is prohibited. The commenter states that such clarification 
would prevent any unintended ``demodification'' of the airplane.
    The FAA agrees with the commenter and has added a new paragraph (g) 
of this supplemental NPRM to specifically prohibit installation of 
those certain pressure relief valves.

Request To Clarify Leak Test Procedure

    One commenter notes that the earlier NPRM would require certain 
airplanes to be modified per Boeing Service Bulletin 737-38-1029, 
Revision 1, dated August 19, 1993, followed by replacement of the 
pressure relief valve per Boeing Service Bulletin 737-38A1047, Revision 
1, dated September 27, 2001. However, the commenter points out that 
each of the service bulletins describes a different leak check 
procedure. The commenter requests that the earlier NPRM specify that 
either leak check procedure is acceptable or state that neither leak 
check procedure is mandated.
    The FAA acknowledges that the two service bulletins describe two 
different leak test (check) procedures. We have determined that the 
leak test described in Boeing Service Bulletin 737-38A1047 is the 
appropriate procedure. Therefore, we have specified in paragraph 
(a)(1)(ii) of this supplemental NPRM that the leak test procedure 
specified in Boeing Service Bulletin 737-38-1029 is not required to be 
performed.

Request To Clarify Note 2 of the NPRM

    One commenter, the manufacturer, states that Note 2 of the earlier 
NPRM could be interpreted to be an acceptable alternative to the entire 
content of paragraph (a)(1) of the NPRM, including the instructions in 
paragraph (a)(1) of the earlier NPRM to perform the requirements of 
paragraph (a)(2) of the NPRM. (Note 2 of the earlier NPRM specifies 
that modification of the potable water pressurization system done in 
accordance with Boeing Service Bulletin 737-38-1029, dated June 6,

[[Page 37107]]

1991, is acceptable for compliance with the requirements of paragraph 
(a)(1) of the earlier NPRM.) The commenter notes that if the 
modification described in the June 6, 1991, revision of the service 
bulletin was installed, the existing pressure relief valve would still 
be installed in the system. Although Note 2 of the earlier NPRM states 
that performance of Boeing Service Bulletin 737-38-1029 is acceptable 
for compliance with paragraph (a)(1), it does not specifically require 
that the new, improved pressure relief valve be installed. The 
commenter suggests that Note 2 of the NPRM be clarified.
    The FAA concurs that clarification is needed to ensure that the 
existing pressure relief valves are replaced with new, improved valves 
for those airplanes identified in the effectivity section of Boeing 
Service Bulletin 737-38-1029. (For reasons other than those discussed 
in this response (see explanation under the heading below labeled 
``Editorial Changes''), we have incorporated the intent of the 
previously designated Notes 2, 3, and 4 of the NPRM into paragraphs 
(a), (d), and (f), respectively, of this supplemental NPRM.)
    This supplemental NPRM revises paragraph (a)(1) of the earlier NPRM 
to specify that paragraph (a)(1) must be accomplished in accordance 
with Boeing Service Bulletin 737-38-1029, dated June 6, 1991, or 
Revision 1, dated August 19, 1993. Including Boeing Service Bulletin 
737-38-1029, dated June 6, 1991, in paragraph (a)(1) of this 
supplemental NPRM makes it unnecessary to provide the ``credit'' 
wording specified in Note 2 of the earlier NPRM. The supplemental NPRM 
further revises paragraph (a)(2) of the earlier NPRM (replacing the 
valve with a new pressure relief valve having part number P/N RV05-362) 
to specify that paragraph (a)(2) must be accomplished in accordance 
with Boeing Service Bulletin 737-38A1047, Revision 2, dated July 18, 
2002.

Request To Limit the Applicability

    One commenter requests that the applicability section of the NPRM 
be revised to include the words, ``except those airplanes that have the 
potable water systems removed or deactivated.'' The commenter states 
that it operates two cargo airplanes that have had the potable water 
systems deactivated. The commenter explains that the servicing port has 
a cap installed and the potable water tank fill and transfer lines have 
been disconnected and plugged. Also, the water tank is vented to 
prevent it from pressurizing during flight.
    The FAA does not agree that the applicability should be revised. 
The FAA has determined that this supplemental NPRM is applicable to 
certain Model 737-100, -200, -200C, -300, -400, and ``500 series 
airplanes. We consider that, while there is currently no potable water 
system on the commenter's fleet, a potable water system could be 
installed at a later date. Therefore, no change to the supplemental 
NPRM is necessary in this regard. For those airplanes that currently 
may not have a potable water system installed, the operators may 
request approval of an alternative method of compliance as provided in 
paragraph (h) of this AD.

Editorial Changes

    Because the language in Notes 2, 3, and 4 of the earlier NPRM is 
regulatory in nature, the intent of those notes has been incorporated 
into paragraphs (a), (d), and (f) of this supplemental NPRM.

Other Changes

    On July 10, 2002, the FAA issued a new version of 14 CFR part 39 
(67 FR 47997, July 22, 2002), which governs the FAA's airworthiness 
directives systems. The regulation now includes material that relates 
to altered products, special flight permits, and alternative methods of 
compliance (AMOC). Because we have now included this material in part 
39, only the office authorized to approve AMOCs is identified in each 
individual AD. Therefore, paragraphs (c) and (d) and Note 1 of the 
original NPRM have been removed from this supplemental NPRM.

Conclusion

    Since these changes expand the scope of the earlier 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 2,049 Model 737-100, -200, -200C, -300, -
400, and -500 series airplanes of the affected design in the worldwide 
fleet. The FAA estimates that 1,144 airplanes of U.S. registry would be 
affected by this proposed AD.
    The FAA estimates that, of the 1,144 airplanes of U.S. registry, 2 
would be affected by the proposed modification of piping to re-locate 
the pressure relief valve, that it would take approximately 6 work 
hours per airplane to accomplish the proposed modification, and that 
the average labor rate is $60 per work hour. Based on these figures, 
the cost impact of the proposed modification of piping on U.S. 
operators is estimated to be $720, or $360 per airplane.
    The FAA estimates that all of the 1,144 airplanes of U.S. registry 
would be affected by the proposed replacement of the pressure relief 
valve, that it would take approximately 2 work hours per airplane to 
accomplish the replacement, and that the average labor rate is $60 per 
work hour. Required parts would cost approximately $300 per airplane. 
Based on these figures, the cost impact of the replacement of the 
pressure relief valve on U.S. operators is estimated to be $480,480, or 
$420 per airplane.
    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. 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 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 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

[[Page 37108]]

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 2000-NM-422-AD.

    Applicability: Model 737-100, -200, -200C, -300, -400, and -500 
series airplanes; line numbers 1 through 2696 inclusive; 
certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent rupture of the potable water tank during flight of 
the airplane, which could result in structural damage to the 
airplane and inability to sustain flight loads, accomplish the 
following:

Modification and Replacement

    (a) For those airplanes listed in the effectivity section of 
Boeing Service Bulletin 737-38-1029, Revision 1, dated August 19, 
1993, on which the modification of the potable water pressurization 
system specified in the service bulletin has not been accomplished: 
Within 18 months after the effective date of this AD, except as 
specified in paragraph (d) of this AD, perform the requirements of 
paragraphs (a)(1) and (a)(2) of this AD.
    (1) Except as specified in paragraphs (a)(1)(i) and (a)(1)(ii) 
of this AD, modify the potable water pressurization system; in 
accordance with Boeing Service Bulletin 737-38-1029, dated June 6, 
1991, or Revision 1, dated August 19, 1993.
    (i) Do not reinstall the existing pressure relief valve having 
part number (P/N) 520A-6DB-50.
    (ii) Do not perform the leak test procedures specified in the 
service bulletin.
    (2) Install a new pressure relief valve having part number P/N 
RV05-362, in accordance with Boeing Service Bulletin 737-38A1047, 
Revision 2, dated July 18, 2002.
    (b) For those airplanes listed in the effectivity section of 
Boeing Service Bulletin 737-38-1029, dated June 6, 1991, or Revision 
1, dated August 19, 1993, on which the modification of the potable 
water pressurization system specified in that service bulletin has 
been accomplished: Within 18 months after the effective date of this 
AD, remove the existing pressure relief valve from the potable water 
tank, and replace the valve with a new pressure relief valve having 
part number P/N RV05-362; in accordance with Boeing Service Bulletin 
737-38A1047, Revision 2, dated July 18, 2002.
    (c) For all other airplanes having line numbers 1 through 2523 
inclusive: Within 18 months after the effective date of this AD 
unless previously accomplished, remove the existing pressure relief 
valve from the potable water tank, and replace the valve with a new 
pressure relief valve having part number P/N RV05-362, in accordance 
with Boeing Service Bulletin 737-38A1047, Revision 2, dated July 18, 
2002.

Acceptable Compliance With Certain Paragraphs

    (d) With the exception of airplanes specified as ``Group 9'' or 
``Group 10'' in Boeing Service Bulletin 737-38A1047, Revision 2, 
dated July 18, 2002, having line numbers 1 through 2523 inclusive: 
Installation of a new pressure relief valve having P/N RV05-362, in 
accordance with Boeing Service Bulletin 737-38A1047, dated November 
9, 2000, or Revision 1, dated September 27, 2001, is acceptable for 
compliance with paragraph (a)(2), (b), or (c) of this AD.

Replacement of Pressure Relief Valve

    (e) For airplanes having line numbers 2524 through 2696 
inclusive, with the exception of those airplanes specified in 
paragraph (f) of this AD: Within 18 months after the effective date 
of this AD, remove the existing pressure relief valve from the 
potable water tank and replace the valve with a new pressure relief 
valve having P/N RV05-362, in accordance with Boeing Service 
Bulletin 737-38A1038, Revision 2, dated September 25, 1997.

Acceptable Compliance With Paragraph (e) of this AD

    (f) For those airplanes having line numbers 2524 through 2696 
inclusive and having air compressors installed in the potable water 
tank pressurization system: Within 18 months after the effective 
date of this AD, remove the existing pressure relief valve from the 
potable water tank and replace the valve with a new pressure relief 
valve having P/N RV05-362, in accordance with Boeing Service 
Bulletin 737-38A1038, dated December 1, 1994; or Revision 1, dated 
February 2, 1995.

Part Installation

    (g) As of the effective date of this AD, no person may install a 
pressure relief valve having P/N 520A-6DB-50, 520A6DB60, or P/N 
D524TP6D60 on any airplane.

Alternative Methods of Compliance

    (h) In accordance with 14 CFR 39.19, the Manager, Seattle 
Aircraft Certification Office, FAA, is authorized to approve 
alternative methods of compliance for this AD.

    Issued in Renton, Washington, on June 17, 2003.
Michael J. Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-15727 Filed 6-20-03; 8:45 am]
BILLING CODE 4910-13-P