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Proposed Rule

Airworthiness Directives; Boeing Model 747-200B, -300, -400, -400D, and -400F Series Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

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AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Boeing Model 747-200B, -300, -400, -400D, and -400F series airplanes, that currently requires repetitive inspections to detect cracking of fire extinguisher discharge tubes in certain engine struts, and corrective action, if necessary. For certain airplanes, that AD also provides for an optional modification of the fire extinguisher discharge tubes, which constitutes terminating action for the repetitive inspections. This action would make the previously optional modification of the fire extinguisher discharge tubes mandatory for all affected airplanes and would add one airplane to the applicability. This proposal is prompted by a report that the check tee valve at the top of an engine strut can be damaged such that no extinguishing agent can get to the engine. The actions specified by the proposed AD are intended to prevent blockage of the check tee valve and cracks in the fire extinguisher discharge tubes in the engine struts, which could prevent the fire extinguishing agent from being delivered to the engine or reduce the amount delivered to the engine, which could permit a fire to spread from the engine to the wing of the airplane.

DATES:

Comments must be received by May 20, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-22-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: 9-anm-nprmcomment@faa.gov. Comments sent via fax or the Internet must contain “Docket No. 2001-NM-22-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 for Windows 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, 1601 Lind Avenue, SW., Renton, Washington.

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FOR FURTHER INFORMATION CONTACT:

Sulmo Mariano, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2686; fax (425) 227-1181. Start Printed Page 15756

End Further Info End Preamble Start Supplemental Information

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 2001-NM-22-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. 2001-NM-22-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On March 30, 2000, the FAA issued AD 2000-07-10, amendment 39-11664 (65 FR 18881, April 10, 2000), applicable to certain Boeing Model 747-200B, -300, -400, -400D, and -400F series airplanes, to require repetitive inspections to detect cracking of fire extinguisher discharge tubes in certain engine struts, and corrective action, if necessary. For certain airplanes, that action also provides for a modification of the fire extinguisher discharge tubes, which constitutes terminating action for the repetitive inspections. That action was prompted by reports that cracked fire extinguisher discharge tubes have been found in the engine struts on certain airplanes. The requirements of that AD are intended to detect and correct cracked fire extinguishing tubes in the engine struts. In the event of an engine fire, such cracked tubes could prevent the fire extinguishing agent from being delivered to the engine or reduce the amount that could be delivered to the engine, and could permit a fire to spread from the engine to the wing of the airplane.

Actions Since Issuance of Previous Rule

Since the issuance of that AD, there has been a report that the check tee valve at the top of the engine strut can be damaged such that no extinguishing agent can reach the engine. The check tee valve contains a ball that directs the extinguishing agent to the engine. It was determined that the ball of the check tee valve could cause a blockage of the downstream part of the check tee valve. Wear between the ball and the housing and the position of the valve would allow the ball to block the outlet port of the check tee valve. The blockage at the check tee valve, if not corrected, could also prevent the fire extinguishing agent from being delivered to the engine or reduce the amount delivered to the engine, and could permit a fire to spread from the engine to the wing of the airplane.

Explanation of Relevant Service Information

Since the issuance of that AD, the FAA has reviewed and approved two service bulletins which describe procedures for modifying the route of the fire extinguisher discharge tubes between the inboard fire bottles and the inboard engines. Boeing Alert Service Bulletin 747-26A2233, Revision 1, dated November 16, 2000, applies to Model 747-400 and 747-400F series airplanes equipped with Pratt & Whitney PW4000 engines. Boeing Alert Service Bulletin 747-26A2267, dated December 20, 2000, applies to Model 747-200B, -300, -400, -400D, and -400F series airplanes equipped with General Electric CF6-80C2 series engines. The modification moves the check tee valve from the top of the strut to a position adjacent to the front spar, and precludes the ball from obstructing the outlet port of the valve. The modification constitutes terminating action for the repetitive inspections required by AD 2000-07-10. Accomplishment of the actions specified in the service bulletins is intended to adequately address the identified unsafe condition.

Explanation of Requirements of Proposed Rule

The FAA has determined that the repetitive inspections of the fire extinguisher discharge tubes, required by AD 2000-07-10, are insufficient to address the unsafe condition which has been identified. The proposed AD would supersede AD 2000-07-10 to continue to require the repetitive inspections but would mandate modification of the routing of the fire extinguisher discharge tubes, terminating the need for repetitive inspections. (That modification was included in AD 2000-07-10 as an optional terminating action for certain airplanes.) In addition, the proposed AD would add an airplane to the applicability to parallel the effectivity specified in Boeing Alert Service Bulletin 747-26A2233, Revision 1, dated November 16, 2000. The proposed AD would require the actions to be accomplished in accordance with the service bulletins described previously, except as discussed below.

Differences Between Service Bulletins and Proposed AD

Operators should note that, although the service bulletins do not provide a compliance time for accomplishing the modification, the proposed AD would require that the modification be accomplished within 24 months after the effective date of this AD. In developing an appropriate compliance time for this AD, the FAA considered not only the manufacturer's recommendation, but also the degree of urgency associated with addressing the unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the modification. In light of all of these factors, the FAA finds a 24-month compliance time for completing the required modification to be warranted, in that it represents an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

Cost Impact

There are approximately 268 airplanes of the affected design in the worldwide fleet. The FAA estimates that 47 airplanes of U.S. registry would be affected by this proposed AD.

The inspections that are currently required by AD 2000-07-10, and retained in this AD, take approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost Start Printed Page 15757impact of the currently required inspections on U.S. operators is estimated to be $2,820, or $60 per airplane, per inspection cycle.

The modification that is proposed in this AD action would take approximately 32 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts would cost approximately $5,488 per airplane. Based on these figures, the cost impact of the proposed requirements of this AD on U.S. operators is estimated to be $348,176, or $7,408 per airplane.

The cost impact figures discussed above are 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.

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List of Subjects in 14 CFR Part 39

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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:

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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. Section 39.13 is amended by removing amendment 39-11664 (65 FR 18881, April 10, 2000), and by adding a new airworthiness directive (AD), to read as follows:

Boeing: Docket 2001-NM-22-AD. Supersedes AD 2000-07-10, Amendment 39-11664.

Applicability: Model 747-200B, -300, -400, -400D, and -400F series airplanes equipped with General Electric CF6-80C2 series engines, line number 679 through 1060 inclusive; and Model 747-400 and 747-400F series airplanes equipped with Pratt & Whitney PW4000 engines, line numbers 696 through 1062 inclusive; certificated in any category.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent blockage of the check tee valve and cracks in the fire extinguisher discharge tubes in the engine struts, which could prevent the fire extinguishing agent from being delivered to the engine or reduce the amount delivered to the engine, which could permit a fire to spread from the engine to the wing of the airplane, accomplish the following:

Restatement of Requirements of AD 2000-07-10

Repetitive Inspections and Corrective Actions

(a) For Model 747-200B, -300, -400, -400D, and -400F series airplanes equipped with General Electric CF6-80C2 series engines, line number 679 through 1060 inclusive; and Model 747-400 and 747-400F series airplanes equipped with Pratt & Whitney PW4000 engines, line numbers 696 through 1061 inclusive: Within 30 days after April 25, 2000 (the effective date of AD 2000-07-10, amendment 39-11664), perform a detailed visual inspection to detect cracking of the fire extinguisher discharge tubes in the number 2 and number 3 engine struts, in accordance with Boeing Alert Service Bulletin 747-26A2266, dated March 3, 2000.

Note 2:

For the purposes of this AD, a detailed visual 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) If no cracking is detected, repeat the inspection thereafter at intervals not to exceed 18 months.

(2) If any cracking is detected, prior to further flight, replace the cracked tube with a new or serviceable part, in accordance with Boeing Alert Service Bulletin 747-26A2266, dated March 3, 2000. Repeat the inspection required by paragraph (a) of this AD within 18 months after the replacement and thereafter at intervals not to exceed 18 months.

New Requirements of This AD

Modification

(b) For Model 747-400 and 747-400F series airplanes equipped with Pratt & Whitney PW4000 engines: Within 24 months after the effective date of this AD, modify the routing of the fire extinguishing tubes between the inboard fire bottles and the inboard engines in accordance with Boeing Alert Service Bulletin 747-26A2233, Revision 1, dated November 16, 2000. Accomplishment of the requirements of this paragraph constitutes terminating action for the repetitive inspections required by paragraph (a) of this AD for Model 747-400 and 747-400F airplanes equipped with Pratt & Whitney PW4000 engines.

(c) For 747-200B, -300, -400, -400D, and -400F series airplanes equipped with General Electric CF6-80C2 series engines: Within 24 months after the effective date of this AD, modify the routing of the fire extinguishing tubes between the inboard fire bottles and the inboard engines in accordance with Boeing Alert Service Bulletin 747-26A2267, dated December 20, 2000. Accomplishment of the requirements of this paragraph constitutes terminating action for the repetitive inspections required by paragraph (a) of this AD for Model 747-200B, -300, -400, -400D, and -400F series airplanes equipped with General Electric CF6-80C2 engines.

Alternative Methods of Compliance

(d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

Note 3:

Information concerning the existence of approved alternative methods of Start Printed Page 15758compliance with this AD, if any, may be obtained from the Seattle ACO.

Special Flight Permits

(e) Special flight permits may be issued in accordance with §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Start Signature

Issued in Renton, Washington, on March 27, 2002.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. 02-7993 Filed 4-2-02; 8:45 am]

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