05-23833. Airworthiness Directives; Boeing Model 747-400 Series Airplanes

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 747-400 series airplanes. This proposed AD would require inspecting the support bracket of the crew oxygen cylinder installation to determine the manufacturing date marked on the support, and performing corrective action if necessary. This proposed AD results from a report indicating that certain oxygen cylinder supports may not have been properly heat-treated. We are proposing this AD to prevent failure of the oxygen cylinder support under the most critical flight load conditions, which could cause the oxygen cylinder to come loose and leak oxygen. Leakage of oxygen could result in oxygen being unavailable for the flightcrew or could result in a fire hazard in the vicinity of the leakage.

DATES:

We must receive comments on this proposed AD by January 23, 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: [phone].
• 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.

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 [phone]; fax [phone].

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-2005-23250; Directorate Identifier 2005-NM-150-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 [phone]) 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 a report indicating that certain supports for the crew oxygen cylinder on Boeing Model 747-400 series airplanes may not have been properly heat-treated during production. These improperly heat-treated supports could fail under the most critical flight load conditions, which could cause the oxygen cylinder to come loose and leak oxygen. Leakage of oxygen could result in oxygen being unavailable for the flightcrew or could result in a fire hazard in the vicinity of the leakage.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 747-35-2114, dated December 19, 2002. The service bulletin describes procedures for inspecting the support bracket of the crew oxygen cylinder installation to determine the manufacturing date marked on the support, and performing corrective action if necessary. The corrective action is replacing, with a new support, any support with a manufacturing date that is within a certain range. 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, except as discussed under “Differences Between the Proposed AD and Service Bulletin.”

Differences Between the Proposed AD and Service Bulletin

The service bulletin specifies a compliance time of 90 days (for airplanes with two crew oxygen cylinders) or 18 months (for airplanes with one crew oxygen cylinder). However, this proposed AD would require all airplanes to be in compliance within 18 months after the effective date of the AD. In developing an appropriate compliance time for this AD, we considered the manufacturer's recommendation, and the degree of urgency associated with the subject unsafe condition. In light of these factors, we find that an 18-month compliance time represents an appropriate interval of time for affected airplanes to continue to operate without compromising safety. This difference has been coordinated with Boeing.

Also, paragraph 1.E., Compliance, of the service bulletin specifies that if the configuration of the crew oxygen cylinder installation is changed from a one-cylinder configuration to a two-cylinder configuration, the actions specified in the service bulletin must be done “immediately.” If the configuration of the crew oxygen cylinder support installation is changed in this way, this proposed AD would require you to do the actions in the service bulletin before further flight after the configuration change, or within 18 months after the effective date of the AD, whichever is later.

Costs of Compliance

There are about 70 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 15 airplanes of U.S. registry. The proposed inspection would take about 1 work hour per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $975, or $65 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.

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

Boeing: Docket No. FAA-2005-23250; Directorate Identifier 2005-NM-150-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by January 23, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 747-400 series airplanes, certificated in any category, as identified in Boeing Special Attention Service Bulletin 747-35-2114, dated December 19, 2002.

Unsafe Condition

(d) This AD results from a report indicating that certain oxygen cylinder supports may not have been properly heat-treated. We are issuing this AD to prevent failure of the oxygen cylinder support under the most critical flight load conditions, which could cause the oxygen cylinder to come loose and leak oxygen. Leakage of oxygen could result in oxygen being unavailable for the flightcrew or could result in a fire hazard in the vicinity of the leakage.

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.

Inspection and Corrective Action

(f) Within 18 months after the effective date of this AD, except as provided by paragraph (g) of this AD: Inspect the support bracket of the crew oxygen cylinder installation to determine the manufacturing date marked on the support, and do the corrective action as applicable, by doing all of the actions in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 747-35-2114, dated December 19, 2002. Corrective action, if applicable, must be done before further flight after the inspection.

(g) If the configuration of the crew oxygen cylinder installation is changed from a one-cylinder to a two-cylinder configuration: Do the actions required by paragraph (f) of this AD before further flight after the change in configuration, or within 18 months after the effective date of this AD, whichever is later.

Parts Installation

(h) On or after the effective date of this AD, no person may install an oxygen cylinder support bracket having part number 65B68258-2 and having a manufacturing date between 10/01/98 and 03/09/01 inclusive (meaning, a manufacturing date of 10/01/98 or later and 03/09/01 or earlier).

Alternative Methods of Compliance (AMOCs)

(i)(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 14 CFR 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Issued in Renton, Washington, on December 2, 2005.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.