00-19670. Airworthiness Directives; Boeing Model 747-100, -200, -300, 747SR, and 747SP Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule; correction.

SUMMARY:

This document corrects information in an existing airworthiness directive (AD) that applies to certain Boeing Model 747-100, -200, -300, 747SR, and 747SP series airplanes. That AD currently requires repetitive inspections 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 document clarifies the applicable compliance time for certain airplanes. This correction is necessary to ensure that fatigue cracking on longeron splice fittings, which could result in reduced controllability of the horizontal stabilizer, is detected and corrected in a timely manner.

DATES:

Effective 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 June 30, 2000 (65 FR 34061, May 26, 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, was approved previously by the Director of the Federal Register as of January 13, 1998 (62 FR 67550, December 29, 1997).

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 [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

On May 18, 2000, the Federal Aviation Administration (FAA) issued AD 2000-10-23, amendment 39-11748 (65 FR 34061, May 26, 2000), which applies to certain Boeing Model 747-100, -200, -300, 747SR, and 747SP series airplanes. That AD requires repetitive inspections 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. That AD was prompted by reports that fatigue cracking was found on longeron splice fittings. The actions required by that AD are intended to detect and correct such fatigue cracking, which could result in reduced controllability of the horizontal stabilizer.

Need for the Correction

Since the issuance of AD 2000-10-23, the manufacturer has informed the FAA that the correct compliance time for certain airplanes is unclear. Paragraph (a)(1) of the AD states the applicable compliance time, “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.” Paragraph (a)(2) of the AD states the applicable compliance time, “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.” The manufacturer points out that the use of the word “or” (“* * * fewer than 17,000 total flight cycles or 63,000 total flight hours * * *”) in paragraph (a)(1) makes it possible that some airplanes may inadvertently be subject to the compliance times in both paragraphs (a)(1) and (a)(2).

The FAA has reviewed this wording and determined that a correction to AD 2000-10-23 is necessary. The FAA's intent is that the compliance times in paragraph (a)(1) apply to airplanes with relatively fewer flight cycles. That is, as of the effective date of this AD, if an airplane's total number of flight cycles is less than 17,000, and the same airplane's total number of flight hours is less than 63,000, then the compliance times in paragraph (a)(1) apply. Therefore, this correction will revise paragraph (a)(1) to state that the compliance time in that paragraph applies to “airplanes that have accumulated fewer than 17,000 total flight cycles and 63,000 total flight hours as of the effective date of this AD.”

Correction of Publication

This document corrects the error and correctly adds the AD as an amendment to § 39.13 of the Federal Aviation Regulations (14 CFR 39.13).

The AD is reprinted in its entirety for the convenience of affected operators. The effective date of the AD remains June 30, 2000.

Since this action only corrects and clarifies a current requirement, it has no adverse economic impact and imposes no additional burden on any person. Therefore, the FAA has determined that notice and public procedures are unnecessary.

List of Subjects in 14 CFR Part 39

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

Adoption of the Correction

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

[Corrected]

2. Section 39.13 is amended by correctly adding the following airworthiness directive (AD):

2000-10-23 Boeing: Amendment 39-11748. Docket 97-NM-88-AD.

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 and 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 §§ 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, was approved previously by the Director of the Federal Register as of June 30, 2000 (65 FR 34061, May 26, 2000).

(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.

Effective Date

(g) The effective date of this amendment remains June 30, 2000.

Issued in Renton, Washington, on July 28, 2000.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.