03-30115. Airworthiness Directives; Boeing Model 747-400 and 747-400D Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-400 and 747-400D series airplanes. This proposal would require a detailed inspection of the fire extinguishing system tube and clamp for correct installation or a repetitive pressure test of the fire extinguishing system tube for leakage, and corrective action, if necessary. This action is necessary to prevent a chafed hole in the fire extinguishing system tube of the aft cargo compartment, which could result in a lack of fire extinguishing agent and consequent uncontained fire in the aft cargo compartment. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by January 20, 2004.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2003-NM-93-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 [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2003-NM-93-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 or 2000 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.

FOR FURTHER INFORMATION CONTACT:

Barbara Mudrovich, Aerospace Engineer, Cabin Safety & 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

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 specified 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 200-NM-93-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. 2003-NM-93-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The FAA has received a report of a chafed hole in the fire extinguishing system tube of the aft cargo compartment on a Boeing Model 747-400 series airplane. During production, the tube was installed incorrectly with the bend down and clamps upside down, which can cause the tube to chafe against a stiffener on the air conditioning duct located below the tube. If the discharge tube has a chafed hole, there may not be a sufficient amount of fire extinguishing agent to extinguish a fire in the aft cargo compartment. This condition, if not corrected, could result in an uncontained fire in the aft cargo compartment.

Explanation of Relevant Service Information

The FAA has reviewed and approved Boeing Service Bulletin 747-26A2270, Revision 1, dated January 16, 2003, which describes the following procedures:

• Performing a detailed inspection of the fire extinguishing system tube and clamps for correct installation, either using an inspection hole and boroscope or with the floor panel removed;
• Performing a repetitive pressure test of the fire extinguishing system tube for leakage; and
• Performing corrective actions, if necessary.

The corrective actions include the following procedures:

• Performing a detailed inspection of the fire extinguishing system tube for chafing/damage;
• Replacing the fire extinguishing system tube with a new tube;
• Repairing the fire extinguishing system tube; and
• Installing the new or repaired fire extinguishing system tube.

Accomplishment of the Part 1—Option 1 or 2 inspections or the Part 2 inspection and repair/replacement in the service bulletin constitutes terminating action for the repetitive pressure test. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously.

Cost Impact

There are approximately 416 airplanes of the affected design in the worldwide fleet. The FAA estimates that 44 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 1 work hour per airplane to accomplish the proposed inspection or pressure test, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $2,860, or $65 per airplane.

The cost impact figure discussed above is 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 proposed 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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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:

Boeing: Docket 2003-NM-93-AD.

Applicability: Model 747-400 and 747-400D series airplanes, as listed in Boeing Service Bulletin 747-26A2270, Revision 1, dated January 16, 2003; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent a chafed hole in the fire extinguishing system tube of the aft cargo compartment, which could result in a lack of fire extinguishing agent and consequent uncontained fire in the aft cargo compartment, accomplish the following:

Service Bulletin References

(a) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Boeing Service Bulletin 747-26A2270, Revision 1, dated January 16, 2003.

Inspection/Pressure Test

(b) Within 6,500 flight hours or 18 months after the effective date of this AD, whichever occurs first, perform the detailed inspection specified in paragraph (b)(1) of this AD or the pressure test specified in paragraph (b)(2) of this AD.

Note 1:

For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

(1) Perform a detailed inspection of the fire extinguishing system tube and clamps for correct installation, either using an inspection hole and boroscope or with the floor panel removed, per the service bulletin.

(i) If the fire extinguishing system tube is installed correctly, no further action is required by this AD.

(ii) If the fire extinguishing system tube is installed incorrectly, prior to further flight, do the actions specified in paragraph (c) of this AD.

(2) Perform a pressure test of the fire extinguishing system tube to check for leakage of the fire extinguishing agent per the service bulletin.

(i) If leakage is not found, repeat the pressure test thereafter at intervals not to exceed 6,500 flight hours or 18 months, whichever occurs first, until the actions specified in paragraph (b)(1) or (c) of this AD have been done.

(ii) If any leakage is found, prior to further flight, do the actions specified in paragraph (c) of this AD.

Removal and Installation/Repair/Replace

(c) Remove the fire extinguishing system tube and do the actions in paragraph (c)(1) or (c)(2) of this AD, as applicable.

(1) If, during the detailed inspection specified in paragraph (b)(1) of this AD, the fire extinguishing system tube was found to be installed incorrectly: Prior to further flight, perform a detailed inspection of the fire extinguishing system tube for chafing/damage per the service bulletin.

(i) If no chafing/damage is found, prior to further flight, install the existing fire extinguishing system tube per Figure 3 of the service bulletin.

(ii) If any chafing/damage is found, prior to further flight, replace the fire extinguishing system tube with a new tube or repair the fire extinguishing system tube, per the service bulletin, and install the new or repaired tube per Figure 3 of the service bulletin.

(2) If, during the pressure test required by paragraph (b)(2) of this AD, leakage was found: Prior to further flight, replace the fire extinguishing system tube with a new tube or repair the fire extinguishing system tube, per the service bulletin, and install the new or repaired tube per Figure 3 of the service bulletin.

Terminating Action

(d) Accomplishment of the actions specified in paragraph (b)(1) or (c) of this AD constitutes terminating action for the requirements of this AD.

Actions Accomplished Per Previous Issue of Service Bulletin

(e) Inspections, repetitive tests and corrective actions accomplished before the effective date of this AD per Boeing Alert Service Bulletin 747-26A2270, dated May 8, 2002, are considered acceptable for compliance with the corresponding action specified in this AD.

Alternative Methods of Compliance

(f) 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.

Issued in Renton, Washington, on November 26, 2003.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.