E8-2353. Airworthiness Directives; Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This proposed AD would require replacing the existing straight-to-90-degree hose assembly for the Lavatory “A” water supply. The replacement is a new straight hose assembly and a separate 90-degree elbow fitting. This proposed AD results from a report of a separated hose assembly for the passenger water system. We are proposing this AD to prevent a water leak into the flight deck ceiling, which could result in an electrical short and possible loss of several functions essential to safe flight.

DATES:

We must receive comments on this proposed AD by March 24, 2008.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Marcia Smith, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2008-0149; Directorate Identifier 2007-NM-319-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

We have received a report of a separated hose assembly for the passenger water system. The hose assembly supplies potable water through a 90-degree end fitting to Lavatory “A.” The break occurred at the 90-degree end fitting when the elbow separated at a soldered joint adjacent to the hose assembly sleeve. The break was located just above and inside the flight deck entry door, and resulted in water spilling into the flight deck ceiling, which affected various radios and the Aircraft Communications Addressing and Reporting System (ACARS) and caused them to become inoperative. These affected parts had to be replaced due to water damage. An analysis of the broken hose assembly showed signs of previous small leaks. It was concluded that an incompletely soldered joint failed and consequently separated. A broken hose assembly in this location, if not corrected, could leak into the flight deck ceiling and result in an electrical short and possible loss of several functions essential to safe flight.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 737-38A1054, dated August 23, 2007. The service bulletin describes procedures for replacing the existing straight-to-90-degree hose assembly for the Lavatory “A” water supply. The replacement is a new straight hose assembly and a separate 90-degree elbow fitting.

FAA's Determination and Requirements of This Proposed AD

We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other airplanes of the same type design. This proposed AD would require accomplishing the actions specified in the service information described previously.

Costs of Compliance

We estimate that this proposed AD would affect 779 airplanes of U.S. registry. We also estimate that it would take between 4 and 7 work-hours per airplane to comply with this proposed AD, depending on the airplane configuration. The average labor rate is $80 per work-hour. Required parts would cost about $400 per product. Based on these figures, we estimate the cost of this proposed AD to the U.S. operators to be between $560,880 and $747,840, or between $720 and $960 per product.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. “Subtitle VII: Aviation Programs,” describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in “Subtitle VII, Part A, Subpart III, Section 44701: General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify 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. 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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. The FAA amends § 39.13 by adding the following new AD:

Boeing: Docket No. FAA-2008-0149; Directorate Identifier 2007-NM-319-AD.

Comments Due Date

(a) We must receive comments by March 24, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 737-38A1054, dated August 23, 2007.

Unsafe Condition

(d) This AD results from a report of a separated hose assembly for the passenger water system. We are issuing this AD to prevent a water leak into the flight deck ceiling, which could result in an electrical short and possible loss of several functions essential to safe flight.

Compliance

(e) Comply with this AD within the compliance times specified, unless already done.

Replacement

(f) Within 60 months after the effective date of this AD, replace the existing straight-to-90-degree hose assembly for the Lavatory “A” water supply with a new straight hose assembly and a separate 90-degree elbow fitting, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-38A1054, dated August 23, 2007.

Parts Installation

(g) As of the effective date of this AD, any hose assembly part having a part number identified in Table 1 of this AD must not be used in any location that is subject to the requirements of this AD. However, those parts may be used in other locations if not otherwise prohibited.

Table 1.—Spare Parts Prohibited for This AD

Airplane group identified in Boeing Alert Service Bulletin 737-38A1054, dated August 23, 2007	Existing part Nos.
1 and 2	10-61998-430, AS4471-08-0401, or AS4471-08-0404.
3	10-61998-25 or 10-60871-125.
4	10-61998-31 or 10-60871-139.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, ATTN: Marcia Smith, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone]; has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

Issued in Renton, Washington, on January 31, 2008.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.