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Proposed Rule

Airworthiness Directives; The Boeing Company Model 747 Airplanes

Document Details

Information about this document as published in the Federal Register.

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Start Preamble

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for all Model 747 airplanes. This proposed AD would require repetitive inspections for cracking in the body skin around the aft corners of the nose wheel well; for certain airplanes, repetitive inspections for cracking in the skin splice plate at the aft corners of the nose wheel well; and related investigative and corrective actions if necessary. This proposed AD would also require repetitive post-modification inspections for cracking in the body skin and the skin splice plate; for certain airplanes, an inspection for steel cross-shaped doublers on the larger aluminum doublers; and corrective action if necessary. This proposed AD would also require repetitive surface high frequency eddy current (HFEC) inspections of a certain bulkhead outer chord, skin splice plate, and outer chord radius filler for cracking; repetitive detailed inspections for cracking of the bulkhead frame web and body skin; and corrective actions if necessary. This proposed AD would provide for optional terminating action for certain repetitive inspections. This proposed AD results from reports of cracking of the fuselage skin and adjacent internal skin splice plate at the left and right nose wheel well aft corners, and the outer chord of the body station (BS) 400 bulkhead. We are proposing this AD to detect and correct cracking of the fuselage skin or splice plate, which, together with cracking of the bulkhead outer chord, could result in large skin cracks and subsequent in-flight rapid decompression of the airplane.

DATES:

We must receive comments on this proposed AD by August 23, 2010.

ADDRESSES:

You may send comments by any of the following methods:

  • Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
  • Fax: 202-493-2251.
  • Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
  • Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this proposed AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​ or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone 800-647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

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 98057-3356; telephone (425) 917-6437; fax (425) 917-6590.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2010-0674; Directorate Identifier 2010-NM-012-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

We have received reports of cracking of the fuselage skin and adjacent internal skin splice plate at the left and right nose wheel well aft corners, and the outer chord of the body station (BS) 400 bulkhead. Cracks were found in the skin on an airplane that had accumulated about 6,355 total flight cycles. In addition, small cracks were found in the outer chord of the body station (BS) 400 bulkhead on airplanes that had accumulated fewer than 20,000 total flight cycles. Cracking of the fuselage skin or splice plate, together with cracking of the bulkhead outer chord, if not detected and corrected, could result in large skin cracks and subsequent in-flight rapid decompression of the airplane.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009. The service bulletin describes procedures for repetitive external detailed inspections for cracking in the body skin around the aft corners of the nose wheel well; for certain airplanes, repetitive external detailed inspections for cracking in the skin splice plate at the aft corners of the nose wheel well, and modification of any cracked aft corners of the nose wheel well by installing modification doublers; and, for certain airplanes, and a one-time external general visual inspection for steel cross-shaped doublers. The modification, which, if accomplished to repair cracks or to eliminate the need for certain repetitive inspections, includes related investigative actions and corrective actions if necessary. The related investigative actions include an open-hole HFEC inspection for cracking at fasteners common to the bulkhead outer chord, and a surface HFEC inspection or penetrant inspection for cracking of the skin if necessary. The corrective actions include repairing the crack, installing cross-shaped doublers, and contacting Boeing for repair instructions and doing the repair.Start Printed Page 39190

The service bulletin also describes procedures for repetitive post-modification inspections, which consist of an external low frequency eddy current (LFEC) inspection for cracking in the skin around fasteners at the periphery of modification doublers, and contacting Boeing for instructions to repair cracks and doing the repair. The service bulletin also describes procedures for repetitive surface HFEC inspections for cracking of a certain bulkhead outer chord, skin splice plate, and outer chord radius filler; repetitive detailed inspections for cracking of the bulkhead frame web and body skin, and corrective actions if necessary. The corrective actions include repairing the crack, or contacting Boeing for repair instructions and repairing if necessary.

FAA's Determination and Requirements of This Proposed AD

We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. This proposed AD would require accomplishing the actions specified in the service information described previously, except as described below.

Differences Between Proposed Rule and Service Bulletin

Boeing Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing 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 the Boeing Commercial Airplanes Organization Designation Authorization (ODA) whom we have authorized to make those findings.

Costs of Compliance

We estimate that this proposed AD would affect 160 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Table—Estimated Costs

ActionWork hoursAverage labor rate per hourCost per productNumber of U.S.-registered airplanesFleet cost
Inspections: Body skin and skin splice plate1$85$85160$13,600.
Modification: Groups 1-3 11808515,300Up to 27Up to $413,100.
Modification: Groups 1-3 23208527,200Up to 27Up to $734,400.
Modification: Groups 4-8 31808515,300Up to 133Up to $2,034,900.
Modification: Groups 4-7 440853,400Up to 44Up to $149,600.
Post-Mod LFEC Inspection 5685510Up to 160Up to $81,600.
Inspections: Bulkhead Outer Chord 6485340Up to 160Up to $54,400.
1 Installation of skin and splice plate doubler for Groups 1-3 airplanes that have not done Boeing Service Bulletin 747-53-2150 or Figure 35 of Section 53-30-03 of the Boeing 747 Structural Repair Manual.
2 Installation of skin and splice plate doubler for Groups 1-3 airplanes that have done Boeing Service Bulletin 747-53-2150 or Figure 35 of Section 53-30-03 of the Boeing 747 Structural Repair Manual.
3 Installation of skin and splice plate doubler for Groups 4-8 airplanes.
4 Installation of splice plate doubler for Groups 4-7 airplanes changed before Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009.
5 Inspection for skin cracks around the fasteners at the periphery of the modification doublers.
6 Includes inspection of the frame web and body skin.

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 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 this 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

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 FAA amends § 39.13 by adding the following new AD:

The Boeing Company: Docket No. FAA-2010-0674; Directorate Identifier 2010-NM-012-AD.Start Printed Page 39191

Comments Due Date

(a) We must receive comments by August 23, 2010.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all The Boeing Company 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.

Subject

(d) Air Transport Association (ATA) of America Code 53: Fuselage.

Unsafe Condition

(e) This AD results from reports of cracking of the fuselage skin and adjacent internal skin splice plate at the left and right nose wheel well aft corners, and the outer chord of the body station (BS) 400 bulkhead. The Federal Aviation Administration is issuing this AD to detect and correct cracking of the fuselage skin or splice plate, which, together with cracking of the bulkhead outer chord, could result in large skin cracks and subsequent in-flight rapid decompression of the airplane.

Compliance

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

Pre-Modification Inspections

(g) For airplanes in Groups 1 through 3, as identified in Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, that have not been modified in accordance with Boeing Service Bulletin 747-53-2150; have not been repaired in accordance with Figure 35 of Section 53-30-03 of Boeing 747 Structural Repair Manual (SRM); and have not been modified in accordance with Boeing Alert Service Bulletin 747-53A2305: Before the accumulation of 3,000 total flight cycles, or within 1,500 flight cycles after the effective date of this AD, whichever occurs later, do an external detailed inspection for cracks in the body skin around the aft corners of the nose wheel well, and skin splice plate at the aft corners of the nose wheel well, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009.

(h) For airplanes in Groups 1 through 3, as identified in Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, that have been modified in accordance with Boeing Service Bulletin 747-53-2150; or repaired in accordance with Boeing 747 Figure 35 of Section 53-30-03 of Boeing 747 SRM: Within 6,000 flight cycles after doing the modification or repair, or within 1,500 flight cycles after the effective date of this AD, whichever occurs later, do an external detailed inspection for cracks in the body skin around the aft corners of the nose wheel well, and skin splice plate at the aft corners of the nose wheel well, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009.

(i) For airplanes in Groups 4 through 7, as identified in Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, that have not been modified in accordance with Boeing Alert Service Bulletin 747-53A2305: Prior to the accumulation of 3,000 total flight cycles, or within 1,500 flight cycles after the effective date of this AD, whichever occurs later, do an external detailed inspection for cracks in the body skin around the aft corners of the nose wheel well, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009.

(j) For airplanes in Groups 4 through 7, as identified in Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, that have been modified in accordance with Boeing Service Bulletin 747-53-2305, dated June 27, 1991; or Revision 1, dated May 22, 1997: Within 1,000 flight cycles after the effective date of this AD, do a one-time external general visual inspection for steel cross-shaped doublers, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009. If no cross-shaped doublers are installed, within 1,500 flight cycles after the effective date of this AD, install cross-shaped doublers, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009.

(k) For airplanes in Group 8, as identified in Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009: Prior to the accumulation of 3,000 total flight cycles, or within 1,500 flight cycles after the effective date of this AD, whichever occurs later, do an external detailed inspection for cracks in the body skin around the aft corners of the nose wheel well, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009.

(l) If no crack is found during any inspection required by paragraph (g), (h), (i), or (k) of this AD, repeat the applicable inspection specified in paragraph (g), (h), (i), or (k) of this AD thereafter at intervals not to exceed 1,500 flight cycles, until the modification specified in paragraph (n) of this AD is accomplished.

(m) If any crack is found during any inspection required by paragraph (g), (h), (i), (k), or (l) of this AD, before further flight, modify the aft corners of the nose wheel well by installing modification doublers and doing all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, except as required by paragraph (t) of this AD.

Optional Terminating Action

(n) Modification of the aft corners of the nose wheel well by installing modification doublers and doing all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, terminates the repetitive inspections required by paragraph (l) of this AD for the modified side only. Where Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, specifies to contact Boeing for appropriate action, repair using a method approved in accordance with the procedures specified in paragraph (u) of this AD.

Post-Modification Repetitive Inspections

(o) For airplanes on which the modification specified in Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, has been done: At the applicable time specified in paragraph (o)(1) or (o)(2) of this AD, do an external low frequency eddy current inspection for skin cracks around the fasteners at the periphery of the modification doublers, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009.

(1) For airplanes on which the edge row fastener holes common to the external modification doublers have been zero-timed in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009: Within 15,000 flight cycles after accomplishing the modification, or within 1,500 flight cycles after the effective date of this AD, whichever occurs later.

(2) For airplanes on which the edge row fastener holes common to the external modification doublers have not been zero-timed in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009: Prior to the accumulation of 15,000 total flight cycles, or within 1,500 flight cycles after the effective date of this AD, whichever occurs later.

(p) If no cracking is found during the inspection required by paragraph (o) of this AD, repeat the inspection specified in paragraph (o) of this AD thereafter at intervals not to exceed 1,500 flight cycles.

(q) If any cracking is found during any inspection required by paragraph (o) or (p) of this AD, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (u) of this AD.

Body Station (BS) 400 Bulkhead Outer Chord Inspection

(r) For all airplanes: At the latest of the times specified in paragraphs (r)(1), (r)(2), and (r)(3) of this AD, do a surface HFEC for cracking in the BS 400 bulkhead outer chord, skin splice plate, and outer chord radius filler; and a detailed inspection for cracking of the bulkhead frame web and body skin; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009. If no cracking is found during any inspection, repeat the inspection one time within 6,000 flight cycles, and thereafter at intervals not to exceed 3,000 flight cycles.

(1) Before the accumulation of 20,000 total flight cycles.

(2) Within 3,000 flight cycles after doing the HFEC inspection required by AD 2004-Start Printed Page 3919207-22 R1, Amendment 39-15326, for structural significant item (SSI) F-4B of the Boeing Document No. D6-35022, “Supplemental Structural Inspection Document (SSID) for Model 747 Airplanes,” Revision G, dated December 2000.

(3) Within 1,500 flight cycles after the effective date of this AD.

(s) If any cracking is found during any inspection required by paragraph (r) of this AD, before further flight, repair in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, except as required by paragraph (t) of this AD. Within 6,000 flight cycles after doing the repair, do the inspections specified in paragraph (r) of this AD, and repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles.

Service Bulletin Exception

(t) If any cracking is found during any inspection required by this AD, and Boeing Alert Service Bulletin 747-53A2305, Revision 2, dated January 15, 2009, specifies to contact Boeing for appropriate action: Before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (u) of this AD.

Alternative Methods of Compliance (AMOCs)

(u)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6437; fax (425) 917-6590. Information may be e-mailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD if it is approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that 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 June 29, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.

End Signature End Part End Supplemental Information

[FR Doc. 2010-16551 Filed 7-7-10; 8:45 am]

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