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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. 97-NM-88-AD; Amendment 39-11748; AD 2000-10-23] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Final rule. 

# SUMMARY:

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 747-100, -200, -300, 747SR, and 747SP series airplanes, that currently requires a one-time inspection to detect cracking of the longeron splice fittings at stringer 11, on the left and right sides at body station 2598, and replacement of any cracked fitting with a new fitting. This amendment reduces the compliance time for accomplishment of the currently required inspection and adds a new requirement for repetitive inspections. This amendment is prompted by reports that fatigue cracking was found on longeron splice fittings. The actions specified by this AD are intended to detect and correct such fatigue cracking, which could result in reduced controllability of the horizontal stabilizer. 

# DATES:

Effective June 30, 2000. 

The incorporation by reference of Boeing Alert Service Bulletin 747-53A2410, Revision 2, including Addendum, dated October 30, 1997, as listed in the regulations, is approved by the Director of the Federal Register as of June 30, 2000. 

The incorporation by reference of Boeing Service Bulletin 747-53A2410, Revision 3, including Addendum, dated March 12, 1998, as listed in the regulations, was approved previously by the Director of the Federal Register as of January 13, 1998 (62 FR 67550, December 29 1997). 

# ADDRESSES:

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 Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 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:

Rick Kawaguchi, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-1153; fax (425) 227-1181. 

# SUPPLEMENTARY INFORMATION:

                    A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 97-26-21, amendment 39-10264 (62 FR 67550, December 29 1997), which is applicable to certain Boeing Model 747-100, -200, -300, 747SR, and 747SP series airplanes, was published in the                     **Federal Register**                     on February 22, 2000 (65 FR 8667). The action proposed to continue to require a one-time inspection to detect cracking of the longeron splice fittings at stringer 11, on the left and right sides at body station 2598, and replacement of any cracked fitting with a new fitting. The action also proposed to reduce the compliance time for accomplishment of the currently required inspection and add a new requirement for repetitive inspections.                 

## Comments 

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public. 

## Conclusion 

The FAA has determined that air safety and the public interest require the adoption of the rule as proposed. 

## Cost Impact 

There are approximately 685 airplanes of the affected design in the worldwide fleet. The FAA estimates that 99 airplanes of U.S. registry will be affected by this AD. 

The inspection that is currently required by AD 97-26-21 takes approximately 32 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. 

Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $190,080, or $1,920 per airplane. 

This AD requires the same inspection currently required by AD 97-26-21 to be accomplished repetitively. Therefore, the cost impact of the requirements of this AD on U.S. operators is estimated to be $190,080, or $1,920 per airplane, per inspection cycle. 

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. 

## 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                           ( print page 34062)                        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. 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 39-10264 ( 62 FR 67550, December 29 1997), and by adding a new airworthiness directive (AD), amendment 39-11748, to read as follows:

**2000-10-23 Boeing**                            : Amendment 39-11748. Docket 97-NM-88-AD. Supersedes AD 97-26-21, Amendment 39-10264.                        

*Applicability:*                             Model 747-100, 747-200, 747-300, 747SR, and 747SP series airplanes; having line positions 201 through 886 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 detect and correct fatigue cracking of the longeron splice fittings at stringer 11, which could result in reduced controllability of the horizontal stabilizer, accomplish the following: 

## Initial Inspection 

(a) Perform a one-time detailed visual inspection to detect cracking of the longeron fittings at stringer 11, on the left and right sides at body station 2598, at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2410, Revision 2, dated October 30, 1997, including Addendum; or Boeing Service Bulletin 747-53A2410, Revision 3, dated March 12, 1998, including Addendum. After the effective date of this AD, only Revision 3 shall be used. 

(1) For airplanes that have accumulated fewer than 17,000 total flight cycles or 63,000 total flight hours as of the effective date of this AD: Inspect at the later of the times specified in paragraph (a)(1)(i) or (a)(1)(ii) of this AD. 

(i) Prior to the accumulation of 17,000 total flight cycles or 63,000 total flight hours, whichever occurs first. 

(ii) Within 1,800 flight cycles or 7,000 flight hours after the effective date of this AD, whichever occurs first. 

(2) For airplanes that have accumulated 17,000 total flight cycles or more, or 63,000 total flight hours or more, as of the effective date of this AD: Inspect at the earlier of the times specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD. 

(i) Prior to the accumulation of 22,000 total flight cycles or 78,000 total flight hours, whichever occurs first. 

(ii) Within 1,800 flight cycles or 7,000 flight hours after the effective date of this AD, whichever occurs first. 

# Note 2:

Where there are differences between the AD and the service bulletin, the AD prevails.

# Note 3:

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 Inspections 

(b) If no crack is found during the inspection required by paragraph (a) of this AD, repeat the inspection one time at the later of the times specified in paragraphs (b)(1) and (b)(2) of this AD, and thereafter at intervals not to exceed 3,000 flight cycles or 18,000 flight hours, whichever occurs first. 

(1) Within 3,000 flight cycles or 18,000 flight hours after accomplishment of the most recent inspection, whichever occurs first. 

(2) Within 1,800 flight cycles or 7,000 flight hours after the effective date of this AD, whichever occurs first. 

## Replacement and Repetitive Inspections 

(c) If any crack is found during any inspection required by paragraph (a) or (b) of this AD: Prior to further flight, replace the cracked fitting with a new fitting, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2410, Revision 2, dated October 30, 1997, including Addendum; or Boeing Service Bulletin 747-53A2410, Revision 3, dated March 12, 1998, including Addendum. After the effective date of this AD, only Revision 3 shall be used. Then, repeat the inspection specified in paragraph (a) of this AD at the later of the times specified in paragraphs (c)(1) and (c)(2) of this AD, and thereafter at intervals not to exceed 3,000 flight cycles or 18,000 flight hours, whichever occurs first. 

(1) Within 17,000 flight cycles or 63,000 flight hours after replacement, whichever occurs first. 

(2) Within 1,800 flight cycles or 7,000 flight hours after the effective date of this AD, whichever occurs first. 

## 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, Transport Airplane Directorate. 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 4:

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 

(e) Special flight permits may be issued in accordance with sections 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 

(f) The actions shall be done in accordance with Boeing Alert Service Bulletin 747-53A2410, Revision 2, including Addendum, dated October 30, 1997; or Boeing Service Bulletin 747- 53A2410, Revision 3, including Addendum, dated March 12, 1998. 

(1) The incorporation by reference of Boeing Service Bulletin 747-53A2410, Revision 3, including Addendum, dated March 12, 1998, 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 747-53A2410, Revision 2, including Addendum, dated October 30, 1997, was approved previously by the Director of the Federal Register as of January 13, 1998 (62 FR 67550, December 29 1997). 

(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. 

(g) This amendment becomes effective on June 30, 2000. 

      ( print page 34063)    
Issued in Renton, Washington, on May 18, 2000. 

Donald L. Riggin, 

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 00-13086 Filed 5-25-00; 8:45 am] 

BILLING CODE 4910-13-U