03-31853. Airworthiness Directives; Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, that requires 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, this AD also requires modification of certain piping to re-locate the pressure relief valve. This action is necessary to prevent rupture of the potable water tank during flight of the airplane, which could result in structural damage to the airplane and its inability to sustain flight loads. This action is intended to address the identified unsafe condition.

DATES:

Effective February 4, 2004.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of February 4, 2004.

ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplane Group, PO Box 3707, Seattle, Washington 98124-2207. This information may be examined at the Federal Aviation Administration (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.

FOR FURTHER INFORMATION CONTACT:

Don Eiford, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

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 737-100, -200, -200C, -300, -400, and -500 series airplanes was published as a supplemental Notice of Proposed Rulemaking in the Federal Register on June 23, 2003 (68 FR 37105). That action proposed to require 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 action also proposed to require modification of certain piping to re-locate the pressure relief valve. For certain airplanes, that action proposed to revise the earlier proposed AD by correcting procedures for performing the proposed replacement of the pressure relief valve.

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.

Agreement With Proposed AD

Two commenters agree with the proposed AD.

Request for Acceptable Method of Compliance

One commenter requests that Revision 1 of Boeing Service Bulletin 737-38A1047, dated September 27, 2001, be approved as an acceptable method of compliance for the terminating action requirements of the proposed AD. The commenter notes that Revision 2 of the service bulletin states that no more work is necessary on airplanes changed per Revision 1.

The FAA agrees. We have determined that the work instructions that depict the piping and fittings adjacent to the new relief valve are slightly different between Revision 2 and Revision 1 of Boeing Service Bulletin 737-38A1047. We acknowledge that the figures are similar enough to each other that an operator would correctly install the new relief valve per either Revision 1 or Revision 2 of the service bulletin. Consequently, we have revised paragraph (d) of the final rule to remove the qualifying phrase, “With the exception of airplanes specified as ‘Group 9’ or ‘Group 10’ in Boeing Service Bulletin 737-38A1047, Revision 2, dated July 18, 2002.” Such revision of paragraph (d) will permit, for all airplanes, accomplishment of the actions specified in service bulletins issued prior to Revision 2 to be considered as an acceptable means of compliance with paragraph (d) of the final rule. However, Revision 2 was specified in paragraphs (a)(2), (b), and (c) of the proposed AD because it more accurately reflects the airplane installation than previous revisions, and those paragraphs remain unchanged in the final rule.

Conclusion

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Change to Labor Rate Estimate

We have reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary to increase the labor rate used in these calculations from $60 per work hour to $65 per work hour. The cost impact information, below, reflects this increase in the specified hourly labor rate.

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.

We estimate that, of the 1,144 airplanes of U.S. registry, only 2 airplanes will be affected by the required modification of piping to re-locate the pressure relief valve. We estimate that it will take approximately 6 work hours per airplane to accomplish the required actions, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $780, or $390 per airplane.

We also estimate that all of the 1,144 airplanes of U.S. registry will be affected by the required replacement of the pressure relief valve, that it will take approximately 2 work hours per airplane to accomplish the replacement, and that the average labor rate is $65 per work hour. Required parts will 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 $491,920, or $430 per airplane.

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 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.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

2003-26-08 Boeing: Amendment 39-13405. 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 its 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) 520A6DB50.

(ii) Do not perform the leak test procedures specified in the service bulletin.

(2) Install a new pressure relief valve having 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 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 P/N RV05-362, in accordance with Boeing Service Bulletin 737-38A1047, Revision 2, dated July 18, 2002.

Acceptable Compliance With Certain Paragraphs

(d) 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 for Certain Airplanes

(e) For airplanes having line numbers 2524 through 2696 inclusive: 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 for Compliance With Paragraph (e)

(f) For those airplanes having line numbers 2527 through 2696 inclusive and having air compressors installed in the potable water tank pressurization system: Removal of the existing pressure relief valve from the potable water tank and replacement of 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; is acceptable for compliance with the requirements of paragraph (e) of this AD.

Part Installation

(g) As of the effective date of this AD, no person may install a pressure relief valve having P/N 520A6DB50, 520A6DB60, or 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.

Incorporation by Reference

(i) Unless otherwise specified in this AD, the actions shall be done in accordance with the service bulletins listed in Table 1 of this AD, as applicable:

Table 1.—Applicable Service Bulletins

Boeing service bulletin—	Revision—	Date—
737-38-1029	original	June 6, 1991
737-38-1029	Revision 1	August 19, 1993
737-38A1038	original	December 1, 1994
737-38A1038	Revision 1	February 2, 1995
737-38A1038	Revision 2	September 25, 1997
737-38A1047	Revision 2	July 18, 2002

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, PO 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

(j) This amendment becomes effective on February 4, 2004.

Issued in Renton, Washington, on December 19, 2003.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.