E9-23294. Airworthiness Directives; 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

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for all Boeing Model 747 airplanes. This proposed AD would require a general visual inspection to identify any existing repairs of the upper main sill outer chord of the left and right side main entry door number 1, as applicable; repetitive detailed inspections for cracks in the upper main sill of the door(s); and related investigative and corrective actions, if necessary. This proposed AD would also require repetitive inspections for airplanes on which a certain repair is done, and corrective actions if necessary. This proposed AD results from reports of cracks in the main entry door number 1 upper main sill outer chord, along the bend radius of the chord on several airplanes. We are proposing this AD to detect and correct such cracks, which could result in loss of structural integrity of the airplane.

DATES:

We must receive comments on this proposed AD by November 12, 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-2009-0794; Directorate Identifier 2009-NM-035-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 in the main entry door number 1 upper main sill outer chord, along the bend radius of the chord on several airplanes. The cracks have been attributed to fatigue. This condition, if not detected and corrected, could result in loss of structural integrity of the airplane.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-53A2785, dated February 12, 2009. The service bulletin describes procedures for a general visual inspection to identify any existing structural repair manual (SRM) repairs of the upper main sill outer chord of the left and right side main entry door number 1, as applicable, repetitive detailed inspections to detect cracks in the upper main sill of the door(s), and related investigative and corrective actions, if necessary.

The related investigative action is to remove any existing SRM outer chord repair found and do a detailed inspection for cracks of the upper main sill and corrective actions, if necessary.

The corrective actions include:

• For airplanes on which any crack is found in the upper main sill outer chord, install an outer chord repair in accordance with Boeing drawing 691U0145;
• For airplanes on which any existing SRM outer chord repair is removed, install a new repair in accordance with Boeing drawing 691U0145;
• For airplanes on which any crack is found in the frame attachment angles or clips of the upper main sill, replace the cracked angle or clip with a new part; and
• For airplanes on which any crack is found in the upper main sill web, contact Boeing for repair instructions.

The service bulletin also describes procedures for repetitive after-repair inspections of any upper main sill(s) that has been repaired in accordance with Boeing drawing 691U0145. For airplanes on which any crack is found during the after-repair inspections, the service bulletin specifies contacting Boeing for repair instructions.

The compliance time for the initial general visual and detailed inspections is before 9,000 total flight cycles or within 12,000 flight cycles after installation of the Zone 3 modification in accordance with Boeing Service Bulletin 747-53-2272, depending on the configuration of the airplane; or within 1,500 flight cycles after the date on the service bulletin; whichever occurs later. The repetitive interval for the detailed inspection is 6,000 flight cycles. The compliance time for the after-repair inspection is within 15,000 flight cycles after the installation of the repair in accordance with Boeing drawing 691U0145, or within 1,500 flight cycles after the date on the service bulletin, whichever occurs later. The repetitive interval for the after-repair inspection is 3,000 flight cycles. The compliance time for all related investigative and corrective actions is before further flight.

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 discussed under “Differences Between the Proposed AD and the Service Bulletin.”

Differences between the Proposed AD and the Service Bulletin

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.

Where the service bulletin specifies a compliance time after the date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.

Costs of Compliance

We estimate that this proposed AD would affect 165 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

Action	Work hours	Average labor rate per hour	Parts	Cost per product	Number of U.S.- registered airplanes	Fleet cost
Inspection (groups 1, 3)	6	$80	$0	$480, per inspection cycle	Up to 165	Up to $79,200, per inspection cycle.
Inspection (groups 2, 4)	3	80	0	$240, per inspection cycle	Up to 165	Up to $39,600, per inspection cycle.

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.

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 adding the following new AD:

Boeing: Docket No. FAA-2009-0794; Directorate Identifier 2009-NM-035-AD.

Comments Due Date

(a) We must receive comments by November 12, 2009.

Affected ADs

(b) None.

Applicability

(c) This AD applies 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, certificated in any category.

Subject

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

Unsafe Condition

(e) This AD results from reports of cracks in the main entry door number 1 upper main sill outer chord, along the bend radius of the chord on several airplanes. The Federal Aviation Administration is issuing this AD to detect and correct such cracks, which could result in loss of 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.

Inspections

(g) At the applicable times specified in Table 1 of paragraph 1.E. “Compliance” of Boeing Alert Service Bulletin 747-53A2785, dated February 12, 2009, except as required by paragraphs (j), (k), and (l) of this AD: Do a general visual inspection to identify any existing structural repair manual (SRM) repairs of the upper main sill outer chord of the left and right side main entry door number 1, as applicable; a detailed inspection for cracks in the upper main sill of the door(s); and do all related investigative and corrective actions, as applicable; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2785, dated February 12, 2009. Do all applicable related investigative and corrective actions before further flight.

(h) For airplanes identified in paragraphs (h)(1) and (h)(2) of this AD: Repeat the detailed inspection described in paragraph (g) of this AD thereafter at the interval specified in Table 1 of paragraph 1.E. “Compliance” of Boeing Alert Service Bulletin 747-53A2785, dated February 12, 2009, until the outer chord repair specified in drawing 691U0145 is done on the upper main sill, in accordance with the Accomplishment Instructions of the Boeing Alert Service Bulletin 747-53A2785, dated February 12, 2009.

(1) Airplanes on which no cracking is found and no existing SRM outer chord repair is found during any inspection required by paragraph (g) of this AD.

(2) Airplanes on which sill web or frame attachment angles (or clips) are repaired or replaced in accordance with Boeing Alert Service Bulletin 747-53A2785, dated February 12, 2009, and the drawing 691U0145 outer chord repair is not installed in accordance with Boeing Alert Service Bulletin 747-53A2785, dated February 12, 2009.

(i) For airplanes on which the outer chord repair specified in drawing 691U0145 has been installed in accordance with Boeing Alert Service Bulletin 747-53A2785, dated February 12, 2009: At the applicable times specified in Table 2 of paragraph 1.E. “Compliance” of Boeing Alert Service Bulletin 747-53A2785, dated February 12, 2009, except as required by paragraph (l) of this AD, do the after-repair inspections and all applicable corrective actions in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2785, dated February 12, 2009, except as provided by paragraph (k) of this AD. Repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles.

Credit for Inspections Required by AD 2005-20-30 or AD 2006-05-02

(j) Accomplishing the inspections required by AD 2005-20-30 or AD 2006-05-02, as applicable, is an acceptable method of compliance for the inspections required by paragraph (g) of this AD. For any airplane that has accumulated 22,000 total flight cycles or more, AD 2005-20-30 requires accomplishing the inspections in accordance with Boeing Service Bulletin 747-53A2349, Revision 2, dated April 3, 2003; and AD 2006-05-02 requires accomplishing the inspections in accordance with Boeing Alert Service Bulletin 747-53A2500, dated December 21, 2004.

Exceptions to the Service Bulletin

(k) If any crack is found during any inspection required by this AD, and Boeing Alert Service Bulletin 747-53A2785, dated February 12, 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 (m) of this AD.

(l) Where Boeing Alert Service Bulletin 747-53A2785, dated February 12, 2009, specifies a compliance time “after the date on this service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD.

Alternative Methods of Compliance (AMOCs)

(m)(1) The Manager, Seattle (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 the approval must specifically refer to this AD.

Issued in Renton, Washington, on September 18, 2009.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.