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Proposed Rule

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

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Supplemental notice of proposed rulemaking; reopening of comment period.

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: 9-anm-nprmcomment@faa.gov. 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.

Start Further Info

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.

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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 Start Printed Page 37106specified 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:

  • 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.
  • For each issue, state what specific change to the proposed AD is being requested.
  • 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, Start Printed Page 371071991, 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.

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List of Subjects in 14 CFR Part 39

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The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Start Printed Page 37108Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[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.

Start Signature

Issued in Renton, Washington, on June 17, 2003.

Michael J. Kaszycki,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 03-15727 Filed 6-20-03; 8:45 am]

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