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Proposed Rule

Airworthiness Directives; Boeing Model 737-300, -400, -500, -600, -700, -800 and -900 Series Airplanes; and Model 757-200 and -300 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.

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AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 737-300, -400, -500, -600, -700, -800 and -900 series airplanes; and Model 757-200 and -300 series airplanes. This proposed AD would require modifying the activation mechanism in the chemical oxygen generator of each passenger service unit (PSU). This proposed AD results from several reports indicating that some chemical oxygen generators failed to activate during in-flight decompression events. These failures were due to fracture of components between the passenger oxygen mask and the release pin in the oxygen generator. We are proposing this AD to prevent failure of the activation mechanism of the chemical oxygen generator, which could result in the unavailability of supplemental oxygen and possible incapacitation of passengers and cabin crew during an in-flight decompression.

DATES:

We must receive comments on this proposed AD by August 28, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

  • DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
  • Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, Washington, DC 20590.
  • Fax: (202) 493-2251.
  • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for the service information identified in this proposed AD.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Susan Letcher, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6474; fax (425) 917-6590.

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SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2006-25336; Directorate Identifier 2006-NM-070-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

We have received several reports indicating that some chemical oxygen generators failed to activate during in-flight decompression events. These failures were due to fracture of components between the passenger oxygen mask and the release pin in the oxygen generator. The release pin must be pulled out of the oxygen generator firing mechanism to activate the generator. The fractures occur when a passenger encounters resistance when attempting to pull down the oxygen mask. The system is designed so that when a mask is pulled down for donning, a lanyard attached to the mask pulls down on a release cable within the passenger service unit (PSU). The release cable is attached to a pin in the oxygen generator firing mechanism. Downward pressure applied on the release cable when the mask is pulled down causes the pin to be pulled out of the firing mechanism, activating the generator and starting the flow of oxygen to the masks. If excessive resistance occurs when pulling down the mask, the components between the mask and the generator release pin can break, such as the tab that connects the oxygen mask to the lanyard or the ring that attaches the lanyard to the release cable. Failure of the activation mechanism of the chemical oxygen generator could result in the unavailability of supplemental oxygen and possible incapacitation of passengers and cabin crew during an in-flight decompression.

Relevant Service Information

We have reviewed the service bulletins identified in the following table. The service bulletins describe Start Printed Page 39594procedures for modifying the activation mechanism in the chemical oxygen generator of each PSU. The modification includes replacing the oxygen generator release pin; reworking the center cable guides; replacing the pulley guards/covers, and adding a pulley configuration placard.

Service Bulletins

Boeing special attention service bulletinApplicable to model/series—
737-25-1545, dated September 8, 2005737-600, -700, -800, and -900.
737-25-1548, dated November 22, 2005737-300, -400, and -500.
757-25-0284, dated November 22, 2005757-200.
757-25-0285, dated November 22, 2005757-300.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously.

Costs of Compliance

There are about 3,283 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 815 airplanes of U.S. registry. The proposed modification would take about 1 work hour per PSU, per airplane, at an average labor rate of $80 per work hour. Required parts would cost between $68 and $75 per PSU, per airplane. Based on these figures, the estimated cost of the modification proposed by this AD for U.S. operators is between $148 and $155 per PSU, per airplane.

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 have 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 that the 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

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List of Subjects in 14 CFR Part 39

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The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

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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.

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[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2006-25336; Directorate Identifier 2006-NM-070-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by August 28, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 737-300, -400, -500, -600, -700, -800 and -900 series airplanes; and Model 757-200 and -300 series airplanes; certificated in any category; as identified in the applicable service bulletin in Table 1 of this AD.

Table 1.—Service Bulletins

Boeing special attention service bulletinDateApplicable to model/series
737-25-1545September 8, 2005737-600, -700, -800, and -900.
737-25-1548November 22, 2005737-300, -400, and -500.
757-25-0284November 22, 2005757-200.
757-25-0285November 22, 2005757-300.
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Unsafe Condition

(d) This AD results from several reports indicating that some chemical oxygen generators failed to activate during in-flight decompression events. These failures were due to fracture of components between the passenger oxygen mask and the release pin in the oxygen generator. We are issuing this AD to prevent failure of the activation mechanism of the chemical oxygen generator, which could result in the unavailability of supplemental oxygen and possible incapacitation of passengers and cabin crew during an in-flight decompression.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Modification

(f) Within 60 months after the effective date of this AD: Modify the activation mechanism in the chemical oxygen generator of each passenger service unit (PSU) by doing all the applicable actions specified in the Accomplishment Instructions of the applicable service bulletin in Table 1 of this AD.

Alternative Methods of Compliance (AMOCs)

(g)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

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Issued in Renton, Washington, on July 6, 2006.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. E6-11021 Filed 7-12-06; 8:45 am]

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