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Proposed Rule

Airworthiness Directives; Boeing Model 747 Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede three existing airworthiness directives (ADs) that apply to certain Boeing Model 747 airplanes. The existing ADs currently require repetitive inspections of the body station (BS) 2598 bulkhead, and corrective action if necessary. This proposed AD would add a requirement to modify the bulkhead, including a one-time inspection and corrective action if necessary, which would terminate certain repetitive inspections. This proposed AD would also require a post-modification inspection of the modified area. This proposed AD results from new reports of cracking in all three areas that require inspection in accordance with the existing ADs. We are proposing this AD to prevent fatigue cracking of the BS 2598 bulkhead structure, which could result in inability of the structure to carry horizontal stabilizer flight loads, and reduced controllability of the airplane.

DATES:

We must receive comments on this proposed AD by December 5, 2005.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

  • DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
  • Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
  • Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590.
  • Fax: (202) 493-2251.
  • Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for service information identified in this proposed AD.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Nicholas Kusz, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6432; fax (425) 917-6590.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Include the docket number “Docket No. FAA-2005-22715; Directorate Identifier 2005-NM-108-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone Start Printed Page 60745(800) 647-5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

We have issued the ADs listed in the following table.

Existing ADs

ADAmendmentFederal Register referenceRequirements
2001-14-0739-1231866 FR 36443 (July 12, 2001)Repetitive high-frequency eddy current (HFEC) inspections to detect cracking of the bulkhead frame support at body station 2598 under the hinge support fittings of the horizontal stabilizer, and repair if necessary.
2001-15-0339-1233766 FR 38365 (July 24, 2001)Repetitive HFEC inspections to detect cracking of the forward and aft inner chords and the splice fitting of the forward inner chord of the body station 2598 bulkhead, and repair if necessary.
2003-19-0839-1331168 FR 54990 (September 22, 2003)Repetitive detailed inspections to detect discrepancies of certain areas of the forward and aft sides of the body station 2598 bulkhead, and repair if necessary.

The existing ADs apply to airplanes having line numbers 1 through 1307 inclusive. The existing ADs were prompted by reports of fatigue cracking on the body station 2598 bulkhead.

We issued those ADs to detect and correct discrepancies of the bulkhead structure, which could result in the inability of the structure to carry horizontal stabilizer flight loads, and reduced controllability of the airplane.

Actions Since Existing AD Was Issued

Since we issued those ADs, we have received additional reports of cracking in all three of the areas addressed in the existing ADs. The cracking was found on Model 747-200B, 747-200F, and 747-400 series airplanes. Also, we received a report of cracking found in all three areas on one airplane.

ADs 2001-15-03 and 2003-19-08 considered the requirements “interim action” and indicated that the manufacturer was developing a modification to address the unsafe condition. Those ADs explained that we may consider further rulemaking if a modification is developed, approved, and available. The manufacturer now has developed such a modification, and we have determined that further rulemaking is indeed necessary; this proposed AD follows from that determination.

Relevant Service Information

We have reviewed Boeing Service Bulletin 747-53-2473, dated March 24, 2005. The service bulletin describes procedures for modifying the bulkhead. The modification involves:

  • Inspecting specified areas using surface high-frequency eddy current (HFEC) and open-hole HFEC methods to detect cracks;
  • Repairing cracks;
  • Removing the bulkhead upper and lower diagonal braces by using a special tool between their attachment fittings to lift and hold the horizontal stabilizer;
  • Installing the following on the aft side of the bulkhead on both sides of the airplane: Two web doublers, new upper and lower hinge backup fittings, and either a new inner chord or the original inner chord that has been inspected for cracks and repaired if necessary; and
  • Installing oversize fasteners at specified locations where insurance cuts have been made to remove material that could contain an undetected crack.

AD 2003-19-08 refers to Boeing Alert Service Bulletin 747-53A2467, dated July 26, 2001, as the appropriate source of service information for the required actions. Boeing has since issued Revision 1, dated April 28, 2005. Revision 1 clarifies certain instructions, but the procedures are essentially the same as those in the original service bulletin.

AD 2001-14-07 refers to Boeing Service Bulletin 747-53A2449, Revision 1, dated May 24, 2001, as the appropriate source of service information for the required actions. Boeing has since issued Revision 2, dated March 14, 2002. Revision 2 clarifies certain instructions, but the procedures are essentially the same as those in Revision 1.

AD 2001-15-03 refers to Boeing Alert Service Bulletin 747-53A2427, dated December 17, 1998, and Revision 1, dated October 28, 1999, as the appropriate source of service information for the required actions. Boeing has since issued Revision 2, dated October 5, 2000, and Revision 3, dated September 27, 2001. Revisions 2 and 3 clarify certain instructions, but the procedures are essentially the same as those in the applicable versions cited in AD 2001-15-03.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of the same type design that may be registered in the U.S. at some time in the future. For this reason, we are proposing this AD, which would supersede ADs 2001-14-07, 2001-15-03, and 2003-19-08. This proposed AD would retain the requirements of the existing ADs and add the actions specified in the service bulletin described previously, except as discussed below.

Difference Between the Proposed AD and the Service Bulletin

The service bulletin specifies contacting the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions by either using a method that we approve or using data that meet the certification basis of the airplane and that have been approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization whom we have authorized to make those findings. Start Printed Page 60746

Additional Changes to Existing ADs

Boeing Commercial Airplanes has received a Delegation Option Authorization (DOA). We have revised the existing AD to delegate the authority to approve an alternative method of compliance for any repair specified in this proposed AD to an Authorized Representative for the Boeing Commercial Airplanes DOA rather than the Designated Engineering Representative (DER).

We have changed all references to a “detailed visual inspection” in the existing ADs to “detailed inspection” in this action. Note 1 in this proposed AD defines a detailed inspection.

In the existing ADs, credit for accomplishment of a prior revision of a service bulletin was provided in a note; in this proposed AD, that language has been added to paragraph (f).

Costs of Compliance

There are about 1,147 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

ActionsWork hoursAverage hourly labor ratePartsCost per airplaneNumber of U.S.- registered airplanesFleet cost
Inspection required by AD 2001-14-07 (per inspection cycle)18$65$0$1,170280$327,600
HFEC inspection required by AD 2001-15-03 (per inspection cycle)265013028036,400
Detailed inspection required by AD 2001-15-03 (per inspection cycle)265013028036,400
Inspection required by AD 2003-19-08 (per inspection cycle)465026028072,800
Proposed modification1266533,71641,90628011,733,680

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify that the 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. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

Start List of Subjects

List of Subjects in 14 CFR Part 39

End List of Subjects

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

Start Part

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Start Authority

Authority: 49 U.S.C. 106(g), 40113, 44701.

End Authority
[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by removing amendment 39-12318 (66 FR 36443, July 12, 2001), amendment 39-12337 (66 FR 38365, July 24, 2001), and amendment 39-13311 (68 FR 54990, September 22, 2003), and adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2005-22715; Directorate Identifier 2005-NM-108-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by December 5, 2005.

Affected ADs

(b) This AD supersedes the ADs listed in Table 1 of this AD.

Table 1.—Superseded ADs

ADAmendment
AD Amendment 2001-14-07Amendment 39-12318.
AD Amendment 2001-15-03Amendment 39-12337.
AD Amendment 2003-19-08Amendment 39-13311.

Applicability

(c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes; certificated in any category; line numbers 1 through 1307 inclusive.

Unsafe Condition

(d) This AD results from reports of cracking in areas required to be inspected by the superseded ADs identified in Table 1 of this AD. We are issuing this AD to prevent fatigue cracking of the body station (BS) 2598 bulkhead structure, which could result in inability of the structure to carry horizontal stabilizer flight loads, and reduced controllability of the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within Start Printed Page 60747the compliance times specified, unless the actions have already been done.

Restatement of AD 2001-14-07

Repetitive High Frequency Eddy Current (HFEC) Inspections

(f) Before the accumulation of 10,000 total flight cycles, or within 1,000 flight cycles after August 16, 2001 (the effective date of AD 2001-14-07), whichever occurs later: Do an open-hole HFEC inspection to find cracking of the bulkhead frame support under the hinge support fittings of the horizontal stabilizer on the left and right sides at BS 2598, in accordance with Figure 2 of the Accomplishment Instructions of Boeing Service Bulletin 747-53A2449, Revision 1, dated May 24, 2001; or Revision 2, dated March 14, 2002. Repeat the inspection after that at intervals not to exceed 3,000 flight cycles. Inspections accomplished before August 16, 2001, per Boeing Alert Service Bulletin 747-53A2449, dated June 8, 2000, are considered acceptable for compliance with the applicable inspection specified in this paragraph.

Repair

(g) If any cracking is found during any inspection required by paragraph (f) of this AD, before further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, or using a method approved in accordance with paragraph (n)(5) of this AD.

Restatement of Certain Requirements of AD 2001-15-03

Repetitive Inspections

(h) Do a surface HFEC inspection of the forward and aft inner chords, the frame support, and the splice fitting of the forward inner chord of the upper corner of the station 2598 bulkhead to find cracking, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2427, Revision 2, dated October 5, 2000; or Revision 3, dated September 27, 2001; at the latest of the times specified in paragraphs (h)(1) and (h)(2) of this AD, as applicable. Repeat the inspection after that at intervals not to exceed 1,500 flight cycles.

(1) For airplanes having line numbers 1 through 1241 inclusive:

(i) Before the accumulation of 6,000 total flight cycles.

(ii) Within 500 flight cycles after August 28, 2001 (the effective date of AD 2001-15-03).

(iii) For airplanes inspected before August 28, 2001, in accordance with Boeing Alert Service Bulletin 747-53A2427, dated December 17, 1998 (including inspections of the splice fitting), or Revision 1, dated October 28, 1999: Within 1,500 flight cycles after accomplishment of the last inspection done in accordance with the original service bulletin or Revision 1, as applicable.

(2) For airplanes having line numbers 1242 through 1307 inclusive:

(i) Before the accumulation of 16,000 total flight cycles.

(ii) Within 500 flight cycles after August 28, 2001.

(iii) For airplanes inspected before August 28, 2001, in accordance with Boeing Alert Service Bulletin 747-53A2427, dated December 17, 1998 (including inspections of the splice fitting), or Revision 1, dated October 28, 1999: Within 1,500 flight cycles after accomplishment of the last inspection done in accordance with the original service bulletin or Revision 1, as applicable.

Repair

(i) If any cracking is found during the inspections required by paragraph (h) of this AD, before further flight, repair in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2427, Revision 2, dated October 5, 2000; or Revision 3, dated September 27, 2001; except where the alert service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions, before further flight, repair in accordance with a method approved by the Manager, Seattle ACO, or using a method approved in accordance with paragraph (n)(5) of this AD.

Restatement of AD 2003-19-08

Repetitive Inspections

(j) Before the accumulation of 10,000 total flight cycles, or within 1,000 flight cycles after October 27, 2003 (the effective date of AD 2003-19-08), whichever is later: Do a detailed inspection of the body station 2598 bulkhead for discrepancies (cracking, elongated fastener holes) of the areas specified in paragraphs (j)(1) and (j)(2) of this AD, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2467, dated July 26, 2001; or Revision 1, dated April 28, 2005. Repeat the inspections after that at intervals not to exceed 3,000 flight cycles.

(1) The lower aft inner chords.

(2) The upper aft outer chords, and the diagonal brace attachment fittings, flanges, and rods.

Note 1:

For the purposes of this AD, a detailed inspection is “an intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required.”

Repair

(k) If any discrepancy is found during any inspection required by paragraph (j) of this AD: Before further flight, repair in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2467, dated July 26, 2001; or Revision 1, dated April 28, 2005. If any discrepancy is found and the service bulletin specifies to contact Boeing for appropriate action: Before further flight, repair in accordance with a method approved by the Manager, Seattle ACO, or using a method approved in accordance with paragraph (n)(5) of this AD.

New Requirements of This AD

Modification

(l) Before the accumulation of 20,000 total flight cycles, or within 48 months after the effective date of this AD, whichever occurs later: Modify the bulkhead by doing all applicable actions including surface and open-hole HFEC inspections for cracking of the upper forward inner chord, aft inner chord, upper splice fitting, and frame support fitting, as specified in the Accomplishment Instructions of Boeing Service Bulletin 747-53-2473, dated March 24, 2005. Repair any cracks before further flight in accordance with the service bulletin. Where the service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions: Before further flight, repair the cracks using a method approved in accordance with the procedures specified in paragraph (n) or (n)(5) of this AD. Accomplishment of the modification terminates the repetitive inspections required by paragraphs (f), (h), and (j)(1) of this AD.

Inspection

(m) Within 20,000 flight cycles after the modification required by paragraph (l) of this AD, inspect the body station 2598 bulkhead for cracks, and repair any cracks before further flight, in accordance with a method approved by the Manager, Seattle ACO.

Alternative Methods of Compliance (AMOCs)

(n)(1) The Manager, Seattle ACO, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) AMOCs approved previously according to AD 2000-08-21, amendment 39-11707, and AD 2001-15-03 are approved as AMOCs for the corresponding requirements of paragraphs (h) and (i) of this AD. (AD 2000-08-21 was superseded by AD 2001-15-03.)

(3) AMOCs approved previously according to AD 2001-14-07 are approved as AMOCs for the corresponding requirements of paragraphs (f) and (g) of this AD.

(4) AMOCs approved previously according to AD 2003-19-08 are approved as AMOCs for the corresponding requirements of paragraphs (j) and (k) of this AD.

(5) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD.

Start Signature

Issued in Renton, Washington, on September 28, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 05-20882 Filed 10-18-05; 8:45 am]

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