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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 2000-NM-78-AD; Amendment 39-11794; AD 2000-12-16] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Final rule; request for comments. 

# SUMMARY:

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that currently requires repetitive inspections to detect fatigue cracking or loose or missing fasteners of the aft torque bulkheads of the outboard nacelle struts; and repair, if necessary. This amendment expands the applicability of the existing AD to include certain additional airplanes, and removes certain other airplanes from the applicability of the existing AD. For all airplanes subject to this AD, this amendment also requires accomplishment of a new terminating action. This action is necessary to prevent fatigue cracking and loose or missing fasteners in the aft torque bulkheads of the outboard nacelle struts, which could result in failure of an outboard nacelle strut diagonal brace load path and possible separation of the nacelle from the wing. This action is intended to address the identified unsafe condition. 

# DATES:

Effective July 5, 2000. 

                        The incorporation by reference of Boeing Alert Service Bulletin 747-54A2184, Revision 1, dated May 6, 1999, as listed in the regulations, is approved by the Director of the                         **Federal Register**                         as of July 5, 2000.                     

The incorporation by reference of Boeing Alert Service Bulletin 747-54A2184, dated July 3, 1997, as listed in the regulations, was approved previously by the Director of the Federal Register as of March 18, 1999 (64 FR 10205, March 3, 1999). 

Comments for inclusion in the Rules Docket must be received on or before August 18, 2000. 

# ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2000-NM-78-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 also be sent via the Internet using the following address: 9-anm-iarcomment@faa.gov. Comments sent via the Internet must contain “Docket No. 2000-NM-78-AD” in the subject line and need not be submitted in triplicate. 

The service information referenced in this AD 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; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. 

# FOR FURTHER INFORMATION CONTACT:

Tamara L. Anderson, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2771; fax (425) 227-1181. 

# SUPPLEMENTARY INFORMATION:

On February 22, 1999, the FAA issued AD 99-05-06, amendment 39-11054 (64 FR 10205, March 3, 1999), applicable to certain Boeing Model 747 series airplanes, to require repetitive inspections to detect fatigue cracking or loose or missing fasteners of the aft torque bulkheads of the outboard nacelle struts; and repair, if necessary. That action was prompted by a report indicating that cracking was found in the aft torque bulkheads of the outboard nacelle struts, and by the availability of new service instructions for detecting fatigue cracking that would not have been detected by the required actions of the existing AD. The requirements of that AD are intended to detect and correct such fatigue cracking and loose or missing fasteners, which could result in failure of an outboard nacelle strut diagonal brace load path and possible separation of the nacelle from the wing. 

## Explanation of Relevant Service Information 

                    Since the issuance of AD 99-05-06, the FAA has reviewed and approved Boeing Alert Service Bulletin 747-54A2184, Revision 1, dated May 6, 1999. The alert service bulletin describes procedures for repetitive inspections to detect fatigue cracking or loose or missing fasteners of the aft torque bulkheads of the outboard nacelle struts; and repair, if necessary. These procedures are substantially similar to those described in Boeing Alert Service Bulletin 747-54A2184, dated July 3, 1997, which was referenced in AD 99-05-06 as an appropriate source of service information for accomplishment of certain requirements of that AD. However, Revision 1 of the alert service bulletin adds new airplanes (Group 5) that are subject to the repetitive inspections (and repair, if necessary) described in the original issue of the alert service bulletin and required by AD 99-05-06. For certain airplanes (                    *i.e.,*                     the airplanes listed in Groups 1, 2, and 5 of the alert service bulletin), the alert service bulletin also describes procedures for a terminating action that eliminates the need for the repetitive inspections described in the alert service bulletin for affected airplanes. The terminating action involves installation of doublers and fillers on the forward side of the lower spar fitting. Accomplishment of the actions specified in the alert service bulletin is                           ( print page 37849)                        intended to adequately address the identified unsafe condition.                 

## Explanation of Applicability of This AD 

For airplanes listed in Groups 3 and 4 of the original issue of Boeing Alert Service Bulletin 747-54A2184, paragraph (c) of AD 99-05-06 describes a detailed visual inspection to detect fatigue cracking and loose or missing fasteners of the aft torque bulkheads of the number 1 and number 4 nacelle struts. For these airplanes in Groups 3 and 4, paragraph (d) of AD 99-05-06 states, “Accomplishment of the nacelle strut modifications required in AD 95-13-07, amendment 39-9287 [60 FR 33336, June 28, 1995] * * * constitutes terminating action for the requirements of this AD.” Paragraph (a) of AD 95-13-07 requires accomplishment of the nacelle strut modifications within 56 months after July 28, 1995 (the effective date of that AD). Considering that the compliance time for this modification has now passed, the FAA finds that it is unnecessary in this AD to continue to reference the inspection and terminating action for airplanes listed in Groups 3 and 4 of the alert service bulletin. Therefore, paragraphs (c) and (d) of AD 99-05-06 have not been included in this AD, and the applicability statement of this AD has been revised to include only airplanes listed in Groups 1, 2, and 5 of Revision 1 of the alert service bulletin. 

## Explanation of Requirements of the Rule 

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, this AD supersedes AD 99-05-06 to continue to require repetitive inspections to detect fatigue cracking or loose or missing fasteners of the aft torque bulkheads of the outboard nacelle struts; and repair, if necessary. This AD expands the applicability of the existing AD to include certain additional airplanes, and removes certain other airplanes from the applicability of the existing AD. For all airplanes subject to this AD, this amendment also requires accomplishment of a new terminating action. The actions are required to be accomplished in accordance with the alert service bulletin described previously, except as discussed below. 

## Differences Between Alert Service Bulletin and This AD 

Operators should note that, although the alert service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, this AD requires the repair of those conditions to be accomplished in accordance with a method approved by the FAA, or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the FAA to make such findings. 

In addition, the FAA has determined that there is an error in Item 3.A.5.c. under “Part 4—Terminating Action” in the Accomplishment Instructions of Boeing Alert Service Bulletin 747-54A2184, Revision 1. The words, “as shown by Figure 11,” should read “as shown by Figure 12.” “Note 6” has been included in this AD to clarify this error. 

## Cost Impact 

None of the Model 747 series airplanes affected by this action are on the U.S. Register. All airplanes included in the applicability of this rule currently are operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, the FAA considers that this rule is necessary to ensure that the unsafe condition is addressed in the event that any of these subject airplanes are imported and placed on the U.S. Register in the future. 

Should an affected airplane be imported and placed on the U.S. Register in the future, it would take approximately 15 work hours to accomplish the required inspections, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of these inspections would be $900 per airplane. 

Should an affected airplane be imported and placed on the U.S. Register in the future, it would take approximately 45 work hours to accomplish the required terminating action, at an average labor rate of $60 per work hour. Required parts would cost approximately $8,166 per airplane. Based on these figures, the cost impact of the required terminating action on U.S. operators would be $10,866 per airplane. 

## Determination of Rule's Effective Date 

                    Since this AD action does not affect any airplane that is currently on the U.S. register, it has no adverse economic impact and imposes no additional burden on any person. Therefore, prior notice and public procedures hereon are unnecessary and the amendment may be made effective in less than 30 days after publication in the                     **Federal Register**                    .                 

## Comments Invited 

                    Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption                     **ADDRESSES.**                    All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.                 

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 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 rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. 

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2000-NM-78-AD.” The postcard will be date stamped and returned to the commenter. 

## Regulatory Impact 

The regulations adopted herein will 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 final rule does not have federalism implications under Executive Order 13132. 

                    For the reasons discussed above, I certify that this action (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under DOT Regulatory Policies and Procedures (44                           ( print page 37850)                        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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption                     **ADDRESSES**                    .                

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Incorporation by reference
      - Safety

## Adoption of the Amendment 

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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 

2. Section 39.13 is amended by removing amendment 39-11054 ( 64 FR 10205, March 3, 1999), and by adding a new airworthiness directive (AD) amendment 39-11794, to read as follows: 

**2000-12-16 Boeing:**                             Amendment 39-11794. Docket 2000-NM-78-AD. Supersedes AD 99-05-06, Amendment 39-11054.                         

*Applicability:*                             Model 747 series airplanes; as listed in Groups 1, 2, and 5 of Boeing Alert Service Bulletin 747-54A2184, Revision 1, dated May 6, 1999; 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 (f)(1) 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 fatigue cracking and loose or missing fasteners in the aft torque bulkheads of the outboard nacelle struts, which could result in failure of an outboard nacelle strut diagonal brace load path and possible separation of the nacelle from the wing, accomplish the following: 

## Restatement of Requirements of AD 99-05-06

### Repetitive Detailed Visual Inspections and Repair: Groups 1 and 2 

(a) For airplanes identified as Groups 1 and 2 airplanes in Boeing Alert Service Bulletin 747-54A2184, dated July 3, 1997: Prior to the accumulation of 8,000 total flight cycles, or within 8,000 flight cycles since modification in accordance with AD 95-13-05, amendment 39-9285, or within 30 days after March 18, 1999 (the effective date of AD 99-05-06, amendment 39-11054), whichever occurs latest, perform a detailed visual inspection of the aft torque bulkheads of the number 1 and number 4 nacelle struts to detect fatigue cracking and loose or missing fasteners. The inspection shall be accomplished in accordance with Part I of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-54A2184, dated July 3, 1997, or Revision 1, dated May 6, 1999. 

# Note 2:

There is a typographical error on Sheet 3 of Figure 1 of Boeing Alert Service Bulletin 747-54A2184, dated July 3, 1997. The words “Group 1 airplanes” should read “Groups 1 and 2 airplanes.” 

(1) If no cracking, and no loose or missing fastener, is found, repeat the inspection thereafter at the intervals specified in Figure 1 of the alert service bulletin. 

(2) If any cracking, or any loose or missing fastener, is found, prior to further flight, repair in accordance with Part III of the alert service bulletin. Repeat the inspection thereafter at the intervals specified in Figure 1 of the alert service bulletin. Where the service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate; or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company designated engineering representative (DER) who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD. 

### Repetitive NDT Inspections and Repair: Groups 1 and 2 

(b) For airplanes identified as Groups 1 and 2 airplanes in Boeing Alert Service Bulletin 747-54A2184, dated July 3, 1997: Prior to the accumulation of 8,000 total flight cycles, or within 8,000 flight cycles since modification in accordance with AD 95-13-05, amendment 39-9285, or within 30 days after March 18, 1999, whichever occurs latest, perform a non-destructive test (NDT) inspection of the aft torque bulkheads of the number 1 and number 4 nacelle struts to detect fatigue cracking. The NDT inspection shall be accomplished in accordance with Part II of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-54A2184, dated July 3, 1997, or Revision 1, dated May 6, 1999. 

# Note 3:

The alert service bulletin refers to a variety of NDT inspections, consisting of ultrasonic inspections, surface eddy current inspections, and open-hole eddy current inspections. The logic diagram in Figure 1 of the alert service bulletin states the conditions under which each of these inspections is to be performed.

(1) If no cracking is found, repeat the inspection thereafter at the intervals specified in Figure 1 of the alert service bulletin. 

(2) If any cracking is found, prior to further flight, repair in accordance with Part III of the alert service bulletin. Repeat the inspection thereafter at the intervals specified in Figure 1 of the alert service bulletin. Where the alert service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, repair in accordance with a method approved by the Manager, Seattle ACO; or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company DER who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD. 

## New Requirements of This AD

# Note 4:

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.” 

### Repetitive Detailed Visual Inspections and Repair: Group 5 

(c) For airplanes identified as Group 5 of Boeing Alert Service Bulletin 747-54A2184, Revision 1, dated May 6, 1999: Prior to the accumulation of 8,000 total flight cycles, or within 90 days after the effective date of this AD, whichever occurs later, perform a detailed visual inspection of the aft torque bulkheads of the number 1 and number 4 nacelle struts to detect fatigue cracking and loose or missing fasteners. The inspection shall be accomplished in accordance with Part I of the Accomplishment Instructions of the alert service bulletin. 

(1) If no cracking, and no loose or missing fastener, is found, repeat the inspection thereafter at the intervals specified in Figure 1 of the alert service bulletin. 

                            (2) If any cracking, or any loose or missing fastener, is found, prior to further flight, repair in accordance with Part III of the alert service bulletin. Repeat the inspection thereafter at the intervals specified in Figure 1 of the alert service bulletin. Where the service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions,                                   ( print page 37851)                                repair in accordance with a method approved by the Manager, Seattle ACO, FAA, Transport Airplane Directorate; or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company DER who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.                         

### Repetitive NDT Inspections and Repair: Group 5 

(d) For airplanes identified as Group 5 airplanes in Boeing Alert Service Bulletin 747-54A2184, Revision 1, dated May 6, 1999: Prior to the accumulation of 8,000 total flight cycles, or within 90 days after the effective date of this AD, whichever occurs later, perform an NDT inspection of the aft torque bulkheads of the number 1 and number 4 nacelle struts to detect fatigue cracking. The NDT inspection shall be accomplished in accordance with Part II of the Accomplishment Instructions of the alert service bulletin. 

# Note 5:

The alert service bulletin refers to a variety of NDT inspections, consisting of ultrasonic inspections, surface eddy current inspections, and open-hole eddy current inspections. The logic diagram in Figure 1 of the alert service bulletin states the conditions under which each of these inspections is to be performed.

(1) If no cracking is found, repeat the inspection thereafter at the intervals specified in Figure 1 of the alert service bulletin. 

(2) If any cracking is found, prior to further flight, repair in accordance with Part III of the alert service bulletin. Repeat the inspection thereafter at the intervals specified in Figure 1 of the alert service bulletin. Where the alert service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, repair in accordance with a method approved by the Manager, Seattle ACO; or in accordance with data meeting the type certification basis of the airplane approved by a Boeing Company DER who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD. 

### Terminating Action: Groups 1, 2, and 5

(e) For airplanes identified as Group 1, 2, and 5 airplanes in Boeing Alert Service Bulletin 747-54A2184, Revision 1, dated May 6, 1999: At the time specified in paragraph (e)(1), (e)(2), or (e)(3), as applicable, accomplish the terminating action (installation of doublers and fillers on the forward side of the lower spar fitting) in accordance with the alert service bulletin. Accomplishment of this paragraph constitutes terminating action for the repetitive inspections required by this AD. 

# Note 6:

There is an error in Item 3.A.5.c. under “Part 4—Terminating Action” in the Accomplishment Instructions of Boeing Alert Service Bulletin 747-54A2184, Revision 1. The words, “as shown by Figure 11,” should read “as shown by Figure 12.”

(1) For airplanes in Groups 1, 2, and 5 on which the interim repair described in Part 3 of the Accomplishment Instructions of the alert service bulletin has NOT been accomplished; and Groups 1 and 2 airplanes on which the requirements of AD 95-13-05, amendment 39-9285, have NOT been accomplished: Accomplish the terminating action prior to the accumulation of 8,000 total flight cycles or within 5 years after the effective date of this AD, whichever occurs later. 

(2) For airplanes in Groups 1, 2, and 5 on which the interim repair described in Part 3 of the Accomplishment Instructions of the alert service bulletin HAS been accomplished: Accomplish the terminating action within 3,000 flight cycles after accomplishment of the interim repair, or within 18 months after the effective date of this AD, whichever occurs later. 

(3) For airplanes in Groups 1 and 2 on which the requirements of AD 95-13-05, amendment 39-9285, HAVE been accomplished: Accomplish the terminating action within 8,000 flight cycles after accomplishment of the requirements of AD 95-13-05, amendment 39-9285, or within 5 years after the effective date of this AD, whichever occurs later. 

### Alternative Methods of Compliance 

(f)(1) 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 ACO. 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. 

(2) Alternative methods of compliance, approved previously in accordance with AD 99-05-06, amendment 39-11054, are approved as alternative methods of compliance with this AD. 

# Note 7:

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

### Special Flight Permits 

(g) 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. 

### Incorporation by Reference 

(h) Except as provided in paragraphs (a)(2), (b)(2), (c)(2), and (d)(2) of this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 747-54A2184, dated July 3, 1997, or Boeing Alert Service Bulletin 747-54A2184, Revision 1, dated May 6, 1999. 

(1) The incorporation by reference of Boeing Alert Service Bulletin 747-54A2184, Revision 1, dated May 6, 1999, is approved by the Director of the Federal Register, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 

(2) The incorporation by reference of Boeing Alert Service Bulletin 747-54A2184, dated July 3, 1997, was approved previously by the Director of the Federal Register as of March 18, 1999 (64 FR 10205, March 3, 1999). 

(3) Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. 

(i) This amendment becomes effective on July 5, 2000. 

Issued in Renton, Washington, on June 9, 2000. 

Donald L. Riggin, 

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 00-15181 Filed 6-16-00; 8:45 am] 

BILLING CODE 4910-13-U