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Proposed Rule

Airworthiness Directives; Boeing Model 747-100B SUD, 747-200B, 747-300, 747-400, and 747-400D Series Airplanes

Document Details

Information about this document as published in the Federal Register.

Published Document

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Start Preamble

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 747-100B SUD, 747-300, 747-400, and 747-400D series airplanes; and Model 747-200B series airplanes having a stretched upper deck. This proposed AD would require repetitively inspecting for cracking or discrepancies of the fasteners in the tension ties, shear webs, and frames at body stations 1120 through 1220, and related investigative and corrective actions if necessary. This proposed AD results from new reports of severed tension ties, as well as numerous reports of cracked tension ties, broken fasteners, and cracks in the frame, shear web, and shear ties adjacent to tension ties for the upper deck. We are proposing this AD to detect and correct cracking of the tension ties, shear webs, and frames of the upper deck, which could result in rapid decompression of the airplane.

DATES:

We must receive comments on this proposed AD by October 27, 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 the service information identified in this proposed AD.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6437; fax (425) 917-6590.

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SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Include the docket number “FAA-2005-22383; Directorate Identifier 2005-NM-102-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 DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you 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 (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 previously issued AD 2005-05-08, amendment 39-13997 (70 FR 12113, March 11, 2005). That AD applies to certain Boeing Model 747-100B SUD, -300, -400, and -400D series airplanes. That AD requires a one-time inspection for discrepancies of the fuselage frame to tension tie joints at body stations (BS) 1120 through 1220, and to determine if steel splice plates are installed on the fuselage frames, and related investigative and corrective actions. That AD was prompted by reports of severed tension ties found at the fuselage frame joints at BS 1120 and 1140. These severed tension ties resulted from fatigue cracking due to an incorrect configuration (installation of aluminum splice plates instead of steel splice plates during the manufacturing process).

Since we issued AD 2005-05-08, we have received additional reports of severed tension ties. While these severed tension ties were also attributed to fatigue, the tension ties in these cases were properly configured according to the applicable Boeing Engineering Drawings. We have also received numerous reports of fatigue cracking of tension ties, as well as broken fasteners and cracks in the frame and shear ties adjacent to tension ties for the upper deck between BS 1120 and 1220. Also, we have received reports of cracking in the shear web between the BS 1120 and BS 1140 tension ties. Cracking of the tension ties, shear webs, and frames of the upper deck; if not corrected; could result in rapid decompression of the airplane.

Certain Boeing 747-200B series airplanes have been modified under a certain Boeing-owned supplemental type certificate to include a stretched upper deck (SUD). These airplanes Start Printed Page 53744would also be subject to the same unsafe condition revealed on Boeing Model 747-100B SUD, -300, -400, and -400D series airplanes.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-53A2507, dated April 21, 2005. The service bulletin describes procedures for repetitive “Stage 1” and “Stage 2” inspections for cracking or discrepancies of the fasteners in the tension ties, shear webs, and frames at body stations 1120 through 1220; and related investigative and corrective actions if necessary.

The procedures for Stage 1 inspections involve the following inspections to detect cracking or broken, loose, or missing fasteners:

  • A detailed inspection of the tension ties and steel plates from BS 1120 through BS 1220.
  • A detailed inspection of the shear web components that attach to the BS 1120 and 1140 tension ties.
  • A detailed inspection of each frame from two stringers above to two stringers below the tension ties from BS 1120 through BS 1220.

If no severed tension tie is found during a Stage 1 inspection, but a crack is found in a tension tie, steel plate, shear web component, or frame; or a broken, loose, or missing fastener is found; the service bulletin specifies doing a “Structure Repair,” which includes further investigative actions. Procedures for the Structure Repair include removing fasteners, performing open-hole high frequency eddy current (HFEC) inspections for cracking, repairing any cracking, and installing new fasteners, as applicable. For repairing certain conditions, the service bulletin specifies to contact Boeing for instructions.

If a severed tension tie is found during a Stage 1 inspection, the service bulletin specifies further investigative actions that involve removing certain fasteners and steel plates, and doing additional open-hole HFEC inspections and detailed inspections of certain fastener holes, adjacent tension ties, the frame web, the frame inner chord, the fail-safe chord, shear ties, and fasteners to detect cracking or broken, loose, or missing fasteners. The service bulletin specifies to contact Boeing for instructions for repairing the severed tension tie, and doing the Structure Repair described previously for any other cracks or broken, loose, or missing fasteners.

Stage 2 inspections are more intensive inspections than Stage 1 inspections and are intended for airplanes with a higher number of total flight cycles. Accomplishing the initial Stage 2 inspection eliminates the need for the Stage 1 inspections. The procedures for Stage 2 inspections involve the following actions:

  • Removing certain fasteners and steel plates and performing open-hole HFEC inspections for cracking of the fastener holes in the tension ties, frames, and steel plates.
  • Performing surface HFEC inspections for cracking around other fastener locations and in other areas of the tension ties.
  • Performing a detailed inspection of each entire tension tie and the attaching fasteners to detect cracking or broken, loose, or missing fasteners.
  • Performing a detailed inspection of the shear web components that attach to the tension ties to detect cracking or broken, loose, or missing fasteners.
  • Performing a detailed inspection of each frame from two stringers above to two stringers below the tension ties to detect cracking or broken, loose, or missing fasteners.
  • Performing an open-hole HFEC inspection for cracking of any frame at which an insulation blanket stud goes through a hole in the frame.

If no tension tie is found severed during a Stage 2 inspection, but a crack is found in a tension tie, steel plate, shear web component, or frame; or a broken, loose, or missing fastener is found; the service bulletin specifies doing the Structure Repair, and installing steel plates and new fasteners.

If a severed tension tie is found during a Stage 2 inspection, the service bulletin specifies further investigative actions that involve removing certain fasteners and steel plates, and doing additional detailed inspections of the frame common to the severed tension tie; including the frame web, frame inner chord, fail-safe chord, shear ties, and fasteners; to detect cracking or broken, loose, or missing fasteners. The service bulletin specifies to contact Boeing for instructions for repairing the severed tension tie; and doing the Structure Repair for any other crack or broken, loose, or missing fasteners.

As part of the procedures for the Structure Repair, the service bulletin describes procedures for an “Oversize Hole Repair,” which may be used to repair a crack found in a fastener hole. The procedures for the Oversize Hole Repair include oversizing the hole to remove the crack, doing an open-hole HFEC inspection to make sure the crack has been removed, repeating the oversizing until the crack is removed, and installing new fasteners. The service bulletin specifies contacting Boeing for instructions if cracking is outside specified limits.

The service bulletin also specifies reporting findings from both Stage 1 and Stage 2 inspections to Boeing.

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

Paragraph 1.E., “Compliance,” of the service bulletin specifies a compliance time for the initial Stage 1 inspection of 8,000 total flight cycles, 1,500 flight cycles after the original issue date of the service bulletin, or 4,000 flight cycles after inspection in accordance with Boeing Service Bulletin 747-53-2483, whichever is later. (AD 2005-05-08, described previously, requires inspections in accordance with Boeing Service Bulletin 747-53-2483, Revision 1, dated August 28, 2003.) The repetitive interval for Stage 1 inspections is 4,000 flight cycles. The service bulletin specifies that Stage 1 inspections end when Stage 2 inspections apply. The service bulletin specifies that the initial Stage 2 inspection should be done before the accumulation of 16,000 total flight cycles, or within 1,000 flight cycles after the original issue date of the service bulletin, whichever is later. The service bulletin specifies a repetitive interval of 3,000 flight cycles for the Stage 2 inspections.

Other Relevant Rulemaking

We have previously issued AD 2004-07-22, amendment 39-13566 (69 FR 18250, April 7, 2004). That AD applies to all Boeing Model 747 series airplanes, and requires revising the FAA-approved maintenance or inspection program to include repetitive inspections for discrepancies of various structural significant items (SSIs); as listed in Boeing Document No. D6-35022, “Supplemental Structural Inspection Document (SSID),” Revision G, dated December 2000 (referred to after this as “the SSID”); and repair if necessary. The repetitive inspections of the tension ties that would be required by this proposed AD are approved as an alternative method of compliance for the inspections of SSI F-19A of the SSID, as required by paragraphs (c) and (d) of AD 2004-07-22. All other provisions of AD 2004-07-22 continue to apply.

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 this same type design. For this reason, we are Start Printed Page 53745proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and the Service Bulletin.”

Differences Between the Proposed AD and Service Information

The service bulletin specifies that you may contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require you to repair those conditions in one of the following ways:

  • 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 Delegation Option Authorization Organization whom we have authorized to make those findings.

The Accomplishment Instructions of the service bulletin specifies reporting inspection findings to Boeing. This proposed AD would not require that action. We do not need this information from operators.

The service bulletin specifies a grace period relative to original issue date of the service bulletin; however, this proposed AD would require compliance before the specified compliance time after the effective date of this AD.

These differences have been coordinated with the manufacturer.

Clarification of Compliance Time for Stage 1 Inspections

As explained previously, the referenced service bulletin specifies a compliance time for the Stage 1 inspections of 8,000 total flight cycles, 1,500 flight cycles after the original issue date of the service bulletin, or 4,000 flight cycles after inspection in accordance with Boeing Service Bulletin 747-53-2483, whichever is later. AD 2005-05-08, described previously, requires accomplishment of Boeing Service Bulletin 747-53-2483 for airplanes listed in that service bulletin. However, we find that this proposed AD would apply to certain airplanes not subject to AD 2005-05-08. Thus, we find that, for airplanes not subject to the inspection in Boeing Service Bulletin 747-53-2483, the applicable compliance time for the Stage 1 inspections that would be required by this proposed AD is 8,000 total flight cycles, or 1,500 flight cycles after the effective date of this AD, whichever is later. We have added a statement to paragraph (f)(1) of this proposed AD to clarify this compliance time.

Interim Action

We consider this proposed AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, we may consider additional rulemaking.

Costs of Compliance

There are about 622 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

ActionWork hoursAverage labor rate per hourCost per airplaneNumber of U.S.-registered airplanesFleet cost
Stage 1 Inspection, per inspection cycle *19$65$1,235, per inspection cycle76$93,860, per inspection cycle.*
Stage 2 Inspection, per inspection cycle8365$5,395, per inspection cycle76$410,020, per inspection cycle.
* Completing the initial Stage 2 inspection ends the repetitive Stage 1 inspections.

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

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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 adding the following new airworthiness directive (AD):

Start Printed Page 53746

Boeing: Docket No. FAA-2005-22383; Directorate Identifier 2005-NM-102-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by October 27, 2005.

Affected ADs

(b) Accomplishing the requirements of paragraph (f) of this AD terminates the corresponding inspection requirements for the upper deck tension tie as required by paragraphs (c) and (d) of AD 2004-07-22, amendment 39-13566, as those paragraphs apply to inspections of SSI F-19A, as identified in Boeing Document No. D6-35022, “Supplemental Structural Inspection Document,” Revision G, dated December 2000. All other requirements of AD 2004-07-22 continue to apply.

Applicability: (c) This AD applies to Boeing Model 747-100B SUD, 747-300, 747-400, and 747-400D series airplanes; and Model 747-200 series airplanes having a stretched upper deck; certificated in any category; as identified in Boeing Alert Service Bulletin 747-53A2507, dated April 21, 2005.

Unsafe Condition

(d) This AD results from new reports of severed tension ties, as well as numerous reports of cracked tension ties, broken fasteners, and cracks in the frame, shear web, and shear ties adjacent to tension ties for the upper deck. We are issuing this AD to detect and correct cracking of the tension ties, shear webs, and frames of the upper deck, which could result in rapid decompression of the airplane.

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

Repetitive Inspections and Corrective Actions

(f) Do repetitive detailed and high frequency eddy current inspections, as applicable, for cracking or discrepancies of the fasteners in the tension ties, shear webs, and frames at body stations 1120 through 1220, and related investigative and corrective actions as applicable, by doing all actions in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2507, dated April 21, 2005, except as provided by paragraphs (g) and (h) of this AD. Do the initial and repetitive Stage 1 and Stage 2 inspections at the applicable times specified in Paragraph 1.E., “Compliance,” of the service bulletin, except as provided by paragraphs (f)(1), (f)(2), and (f)(3) of this AD. Any applicable investigative and corrective actions must be done before further flight. Doing the initial Stage 2 inspection ends the repetitive Stage 1 inspections.

(1) For any airplane not identified in and subject to inspections in accordance with Boeing Service Bulletin 747-53-2483: Do the initial Stage 1 inspection in accordance with Boeing Alert Service Bulletin 747-53A2507 before the accumulation of 8,000 total flight cycles, or within 1,500 flight cycles after the effective date of this AD, whichever is later.

(2) Where Paragraph 1.E., “Compliance,” of the service bulletin specifies a compliance time relative to the original issue date of the service bulletin, this AD requires compliance before the specified compliance time after the effective date of this AD.

(3) For any airplane that reaches the applicable compliance time for the initial Stage 2 inspection (as specified in Table 1, Compliance Recommendations, under paragraph 1.E. of the service bulletin) before reaching the applicable compliance time for the initial Stage 1 inspection: Doing the initial Stage 2 inspection eliminates the need to do the Stage 1 inspection.

Exception to Corrective Action Instructions

(g) If any discrepancy; including but not limited to cracking, or broken, loose, or missing fasteners; is found during any inspection required by this AD, and Boeing Alert Service Bulletin 747-53A2507, dated April 21, 2005, specifies to contact Boeing for appropriate action: Before further flight, repair the discrepancy using a method approved in accordance with paragraph (i) of this AD.

No Reporting Requirement

(h) Although Boeing Alert Service Bulletin 747-53A2507, dated April 21, 2005, specifies reporting inspection findings to the manufacturer, this AD does not include that requirement.

Alternative Methods of Compliance (AMOCs)

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

(2) 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 August 24, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 05-17979 Filed 9-9-05; 8:45 am]

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