E9-16463. Airworthiness Directives; Boeing Model 747-100B SUD, 747-200B, 747-300, 747-400, and 747-400D Series Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to all 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. The existing AD currently requires 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 would also require modifying the frame-to-tension-tie joints at body stations 1120 through 1220 (including related investigative actions and corrective actions if necessary), which would provide a terminating action for the repetitive inspections. This proposed AD would also require new repetitive inspections after the modification, corrective actions if necessary, and additional modification requirements at a specified time after the first modification. This proposed AD would also remove certain airplanes from the applicability. This proposed AD results from reports of cracked and severed 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 and reduced structural integrity of the airplane.

DATES:

We must receive comments on this proposed AD by August 27, 2009.

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: [phone].
• 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 [phone], extension 1; fax [phone]; e-mail [e-mail]; 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 or 425-227-1152.

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 [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

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 [phone]; fax [phone].

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-2009-0607; Directorate Identifier 2009-NM-024-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

On November 15, 2007, we issued AD 2007-23-18, amendment 39-15266 (72 FR 65655, November 23, 2007), for all 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. That AD requires 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. That AD resulted from reports of multiple severed adjacent tension ties, in addition to the previous reports of cracked and severed tension ties, broken fasteners, and cracks in the frame, shear web, and shear ties adjacent to tension ties for the upper deck. We issued that AD to detect and correct cracking of the tension ties, shear webs, and frames of the upper deck, which could result in rapid decompression and reduced structural integrity of the airplane.

Actions Since Existing AD Was Issued

In AD 2007-23-18, we required inspection reports because the extent of cracking in the fleet was not known, and we specified that the inspection reports would help determine the damage condition of the fleet. We stated that, based on the results of those reports, we might determine that further corrective action is warranted. Since we issued that AD, the manufacturer has developed a new modification that would terminate the repetitive Stage 1 and Stage 2 inspections required by paragraphs (f) and (i) of AD 2007-23-18. Therefore, further corrective action is warranted; however, this proposed AD does not provide a terminating action for all repetitive inspections.

Boeing has also informed us that Model 747-400 airplanes converted to the 747-400 LCF (large cargo freighter) configuration (airplanes having variable numbers RT631, RT632, RT743, and RT876) no longer have the affected tension ties and, therefore, are not subject to the unsafe condition. These airplanes are no longer included in the effectivity of Boeing Alert Service Bulletin 747-53A2559, dated January 8, 2009, described below.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-53A2559, dated January 8, 2009. The service bulletin describes procedures for modifying the frame-to-tension-tie joints at body stations 1120 through 1220. The modification includes installing a new frame and tension tie structure outboard of approximately buttock line 36, related investigative actions, and corrective actions if necessary. The related investigative actions include a detailed inspection for cracking of the remaining frame structure and tension tie structure and an open-hole high frequency eddy current inspection for cracking of the fastener holes opened during the modification. The corrective actions include contacting Boeing for repair instructions. The service bulletin also describes procedures for repetitive post-modification detailed inspections for cracking from body stations 1120 through 1220. For airplanes on which any crack is found, the service bulletin specifies the corrective action of contacting Boeing for repair instructions. The service bulletin also specifies contacting Boeing for additional modification requirements at a specified time after doing the initial modification.

Modifying the frame-to-tension-tie joints at body stations 1120 through 1220 eliminates the need for the repetitive Stage 1 and Stage 2 inspection requirements of AD 2007-23-18.

The compliance times in Boeing Alert Service Bulletin 747-53A2559, dated January 8, 2009, are:

• For the initial modification: Before the accumulation of 17,000 total flight cycles, or within 3,000 flight cycles after the date on the service bulletin, whichever occurs later.
• For the repetitive post-modification detailed inspections: Within 8,000 flight cycles after the modification, or within 1,000 flight cycles after the date on the service bulletin, whichever occurs later; and repeated thereafter at intervals not to exceed 3,000 flight cycles.
• For repair of any crack: Before further flight after finding the crack. The inspection is repeated thereafter at intervals not to exceed 3,000 flight cycles.
• For the additional modification requirements: Before the accumulation of 14,000 flight cycles after the first modification, or within 1,000 flight cycles after the date on the service bulletin, whichever occurs later.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to develop on other airplanes of the same type design. For this reason, we are proposing this AD, which would supersede AD 2007-23-18 and would retain the requirements of the existing AD. This proposed AD would also require accomplishing the actions specified in the service bulletin described previously, except as discussed under “Difference Between the Proposed AD and the Service Information.”

Difference Between the Proposed AD and the Service Information

The service bulletin 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 an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization whom we have authorized to make those findings.

Related Rulemaking

On December 26, 2007, we issued AD 2004-07-22 R1, amendment 39-15326 (73 FR 1052, January 7, 2008), which is applicable to all 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. (A correction to AD 2004-07-22 R1 was published in the Federal Register on February 14, 2008 (73 FR 8589).) That AD requires that the maintenance inspection program be revised to include inspections that will give no less than the required damage tolerance rating for each structural significant item, and repair of cracked structure. That AD resulted from a report of incidents involving fatigue cracking in transport category airplanes that are approaching or have exceeded their design service objective. We issued that AD to ensure the continued structural integrity of the affected airplanes. The repair and modification procedures of Boeing Alert Service Bulletin 747-53A2559, dated January 8, 2009, are alternative methods of compliance (AMOCs) for paragraphs (h), (i), and (j) of AD 2004-07-22 R1, only for the areas modified as given in the alert service bulletin.

On August 2, 2007, we issued AD 2007-16-19, amendment 39-15158 (72 FR 45151, August 13, 2007), which is applicable to certain Boeing Model 747-200B, 747-300, and 747-400 series airplanes. That AD requires repetitive detailed inspections for cracking of the aft tension tie channels from body station (BS) 1120 to BS 1220 and from BS 880 to BS 1100, and corrective actions if necessary. That AD resulted from cracks found in the aft tension tie channels at four station locations on a Model 747-200B series airplane that had been modified to a special freighter. We issued that AD to detect and correct cracking of the aft tension tie channels; failure of more than one tension tie could result in rapid depressurization of the airplane. The applicable inspection, repair, and modification procedures of Boeing Alert Service Bulletin 747-53A2559, dated January 8, 2009, are AMOCs for paragraph (f) of AD 2007-16-19, only for the areas modified as given in the alert service bulletin.

Changes to Existing AD

This proposed AD would retain the requirements of AD 2007-23-18. Since AD 2007-23-18 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Revised Paragraph Identifiers

Requirement in AD 2007-23-18	Corresponding requirement in this proposed AD
paragraph (f)	paragraph (g).
paragraph (g)	paragraph (h).
paragraph (h)	paragraph (i).
paragraph (i)	paragraph (j).
paragraph (j)	paragraph (k).
paragraph (k)	paragraph (l).

We have removed paragraph (b)(2) of AD 2007-23-18. Global AMOC approval has been previously given to Boeing for AD 2004-07-22 R1. Therefore, that paragraph is no longer necessary.

Interim Action

We consider this proposed AD interim action. If final action is later identified, we might consider further rulemaking then.

Costs of Compliance

There are about 618 airplanes of the affected design in the worldwide fleet, which includes 72 U.S.-registered airplanes. The following table provides the estimated costs for U.S. operators to comply with this proposed AD. The average labor rate is $80 per work hour.

Estimated Costs

Action	Work hours	Parts	Cost per airplane	Fleet cost
Stage 1 inspections (required by AD 2007-23-18)	19	$0	$1,520 per inspection cycle	$109,440 per inspection cycle.
Stage 2 inspections (required by AD 2007-23-18)	83	$0	$6,640	$478,080 per inspection cycle.
Modification (new proposed action)	257 to 263	$341,334 to $345,490	$361,894 to $366,530	$26,056,368 to $26,390,160.1
Post-modification inspections (new proposed action)	6	$0	$480 per inspection cycle	$34,560 per inspection cycle.
1 Depending on airplane configuration.

Because the manufacturer has not yet specified the additional modification actions commensurate with the additional modification specified by this proposed AD, we cannot provide specific information regarding the required number of work hours or the cost of parts to do the proposed additional modification. Additional modification costs will likely vary depending on the operator and the airplane configuration.

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.

List of Subjects in 14 CFR Part 39

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

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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

[Amended]

2. The FAA amends § 39.13 by removing amendment 39-15266 (72 FR 65655, November 23, 2007) and adding the following new AD:

Boeing: Docket No. FAA-2009-0607; Directorate Identifier 2009-NM-024-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by August 27, 2009.

Affected ADs

(b) This AD supersedes AD 2007-23-18.

Applicability

(c) This AD applies to Boeing Model 747-100B SUD, 747-200B, 747-300, 747-400, and 747-400D series airplanes AD, certificated in any category, as identified in Boeing Alert Service Bulletin 747-53A2559, dated January 8, 2009.

Subject

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

Unsafe Condition

(e) This AD results from reports of cracked and severed tension ties, broken fasteners, and cracks in the frame, shear web, and shear ties adjacent to tension ties for the upper deck. The Federal Aviation Administration is 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 and reduced structural integrity 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.

Restatement of the Requirements of AD 2007-23-18

Repetitive Stage 1 Inspections

(g) Do detailed 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 as applicable, by doing all actions specified in and in accordance with “Stage 1 Inspection” of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2507, dated April 21, 2005, except as provided by paragraph (k) of this AD. Do the Stage 1 inspections at the applicable times specified in paragraphs (h) and (i) of this AD, except as provided by paragraphs (g)(1) and (g)(2) of this AD. All applicable related investigative and corrective actions must be done before further flight. Doing the modification required by paragraph (m) of this AD terminates the repetitive inspection requirements of this paragraph.

(1) Where paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2507, dated April 21, 2005, specifies a compliance time relative to the original issue date of the service bulletin, this AD requires compliance before the specified compliance time after April 26, 2006 (the effective date of AD 2006-06-11, amendment 39-14520, which was superseded by AD 2007-23-18).

(2) 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 Boeing Alert Service Bulletin 747-53A2507, dated April 21, 2005) before reaching the applicable compliance time for the initial Stage 1 inspection: Accomplishment of the initial Stage 2 inspection eliminates the need to do the Stage 1 inspections.

Compliance Time for Initial Stage 1 Inspection

(h) Do the initial Stage 1 inspection at the earlier of the times specified in paragraphs (h)(1) and (h)(2) of this AD.

(1) At the earlier of the times specified in paragraphs (h)(1)(i) and (h)(1)(ii) of this AD.

(i) At the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2507, dated April 21, 2005.

(ii) Before the accumulation of 10,000 total flight cycles, or within 250 flight cycles after November 28, 2007 (the effective date of AD 2007-23-18), whichever occurs later.

(2) At the later of the times specified in paragraphs (h)(2)(i) and (h)(2)(ii) of this AD.

(i) Before the accumulation of 12,000 total flight cycles.

(ii) Within 50 flight cycles or 20 days, whichever occurs first, after November 28, 2007.

Compliance Times for Repetitive Stage 1 Inspections

(i) Repeat the Stage 1 inspection specified in paragraph (g) of this AD at the time specified in paragraph (i)(1) or (i)(2), as applicable. Repeat the inspection thereafter at intervals not to exceed 250 flight cycles, until the initial Stage 2 inspection required by paragraph (j) of this AD has been done.

(1) For airplanes on which the initial Stage 1 inspection had not been accomplished as of November 28, 2007: Do the next inspection before the accumulation of 10,000 total flight cycles, or within 250 flight cycles after the initial Stage 1 inspection done in accordance with paragraph (g) of this AD, whichever occurs later.

(2) For airplanes on which the initial Stage 1 inspection had been accomplished as of November 28, 2007: Do the next inspection at the applicable time specified in paragraph (i)(2)(i) or (i)(2)(ii) of this AD.

(i) For airplanes that had accumulated fewer than 12,000 total flight cycles as of November 28, 2007: Do the next inspection before the accumulation of 10,000 total flight cycles, or within 250 flight cycles after November 28, 2007, whichever occurs later.

(ii) For airplanes that had accumulated 12,000 total flight cycles or more as of the effective date of this AD: Do the next inspection at the later of the times specified in paragraphs (i)(2)(ii)(A) and (i)(2)(ii)(B) of this AD.

(A) Within 250 flight cycles after accomplishment of the initial Stage 1 inspection.

(B) Within 50 flight cycles or 20 days, whichever occurs first, after November 28, 2007.

Repetitive Stage 2 Inspections

(j) Do detailed and high frequency eddy current 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 as applicable, by doing all actions specified in and in accordance with “Stage 2 Inspection” of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2507, dated April 21, 2005, except as provided by paragraph (k) of this AD. Do the initial and repetitive Stage 2 inspections at the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2507, dated April 21, 2005. All applicable related investigative and corrective actions must be done before further flight. Accomplishment of the initial Stage 2 inspection ends the repetitive Stage 1 inspections. Doing the modification required by paragraph (m) of this AD terminates the repetitive inspection requirements of this paragraph.

Exception to Corrective Action Instructions

(k) If any discrepancy, including but not limited to cracking, or broken, loose, or missing fasteners, is found during any inspection required by paragraphs (g) through (j) of 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 the procedures specified in paragraph (n) of this AD.

Reporting Requirement

(l) At the applicable time specified in paragraph (l)(1) or (l)(2) of this AD, submit a report of the findings (both positive and negative) of each Stage 1 inspection required by paragraph (g) of this AD to Boeing Commercial Airplanes; Attention: Manager, Airline Support; P.O. Box 3707 MC 04-ER; Seattle, Washington 98124-2207; fax [phone]. The report must include the inspection results, a description of any discrepancies found, the inspections performed, the airplane serial number, and the number of total accumulated flight cycles on the airplane. Under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements contained in this AD and has assigned OMB Control Number 2120-0056.

(1) For any inspection done after November 28, 2007: Submit the report within 30 days after the inspection.

(2) For any inspection done before November 28, 2007: Submit the report within 30 days after November 28, 2007.

New Requirements of This AD

Modification

(m) Except as provided by paragraphs (m)(1) and (m)(2) of this AD: At the times specified in paragraph 1.E, “Compliance,” of Boeing Alert Service Bulletin 747-53A2559, dated January 8, 2009, modify the frame-to-tension-tie joints at body stations 1120 through 1220; do all related investigative and applicable corrective actions; do the repetitive post-modification detailed inspections for cracking of the tension tie and frame structure and all applicable corrective actions; and do the additional modification. Do all actions in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2559, dated January 8, 2009. Modifying the frame-to-tension-tie joints at body stations 1120 through 1220 terminates the repetitive inspection requirements of paragraphs (g) and (j) of this AD.

(1) Where paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2559, dated January 8, 2009, specifies a compliance time relative to the original issue date of the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.

(2) Where Boeing Alert Service Bulletin 747-53A2559, dated January 8, 2009, specifies to contact Boeing for repair instructions or additional modification requirements: Before further flight, repair the discrepancy or do the modification using a method approved in accordance with the procedures specified in paragraph (n) of this AD.

Alternative Methods of Compliance (AMOCs)

(n)(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 [phone]; fax [phone]. Or, e-mail information to [e-mail].

(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 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 14 CFR 25.571, Amendment 45, and the approval must specifically refer to this AD.

(4) AMOCs approved previously in accordance with AD 2007-23-18 are approved as AMOCs for the corresponding requirements of paragraphs (g) and (j) of this AD.

Issued in Renton, Washington, on June 24, 2009.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.