E8-11474. Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

SUMMARY:

We are revising an earlier proposed airworthiness directive (AD) for certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR series airplanes. For certain airplanes, the original NPRM would have required a material type inspection to determine if the lower forward corner reveal of the number 3 main entry doors (MEDs) is a casting. If the reveals are castings, the original NPRM would have required repetitive inspections of the reveals for cracking, and corrective action if necessary. If the reveals are not castings, the original NPRM would have required a detailed inspection of the reveals for a sharp edge and repetitive inspections of the reveals for cracking, and corrective action if necessary. For certain other airplanes, the original NPRM would have required only a detailed inspection of the reveals for a sharp edge and repetitive inspections of the reveals for cracking, and corrective action if necessary. For certain other airplanes, the original NPRM would have required repetitive inspections of the reveals for cracking only, and corrective action if necessary. The original NPRM resulted from reports of cracking and/or a sharp edge in the lower forward corner reveal of the number 3 MEDs. This action revises the original NPRM by reducing the compliance times for doing certain inspections and allowing a certain replacement as an optional action for the material type inspection for certain airplanes. We are proposing this supplemental NPRM to detect and correct fatigue cracking of the lower forward corner reveal of the number 3 MEDs, which could lead to the door escape slide departing the airplane when the door is opened and the slide is deployed, and consequent injuries to passengers and crew using the door escape slide during an emergency evacuation.

DATES:

We must receive comments on this supplemental NPRM by June 16, 2008.

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 AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

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-2007-29227; Directorate Identifier 2007-NM-100-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 issued a notice of proposed rulemaking (NPRM) (the “original NPRM”) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR series airplanes. That original NPRM was published in the Federal Register on September 19, 2007 (72 FR 53498). For certain airplanes, that original NPRM proposed to require a material type inspection to determine if the lower forward corner reveal of the number 3 main entry doors (MEDs) is a casting. If the reveals are castings, that original NPRM proposed to require repetitive inspections of the reveals for cracking, and corrective action if necessary. If the reveals are not castings, that original NPRM proposed to require a detailed inspection of the reveals for a sharp edge and repetitive inspections of the reveals for cracking, and corrective action if necessary. For certain other airplanes, that original NPRM proposed to require only a detailed inspection of the reveals for a sharp edge and repetitive inspections of the reveals for cracking, and corrective action if necessary. For certain other airplanes, that original NPRM proposed to require repetitive inspections of the reveals for cracking only, and corrective action if necessary.

Comments

We gave the public the opportunity to participate in developing this AD. We considered the comments received from the commenter.

Request To Clarify No Further Action Statement

Boeing requests that we clarify the statement “No further action is required by this paragraph for that location only after the replacement” specified in paragraphs (g)(1), (j)(1), (j)(2)(i), (j)(3)(i), (k)(2)(i), and (k)(2)(ii)(B) of the NPRM. Boeing suggests that we add the phrase “with a two-piece reveal” to the statement. Boeing states that the referenced service bulletin (Boeing Special Attention Service Bulletin 747-53-2460, Revision 1, dated February 13, 2007) gives two options for the replacement, with either a one-piece reveal or a two-piece reveal. Boeing states that only a replacement with a two-piece reveal terminates the inspections for that location.

We agree that only replacement with a two-piece reveal would terminate the inspections for that location. However, we do not agree that clarification is necessary for all paragraphs. In paragraphs (j)(2)(i), (j)(3)(i), and (k)(2)(ii)(B) of the supplemental NPRM, we specify replacing the reveal with a new or reworked two-piece reveal in accordance with Part 2 of Boeing Special Attention Service Bulletin 747-53-2460, Revision 1. We do not mention installation of a one-piece reveal as an option in these paragraphs. Part 2 of the service bulletin describes procedures for installing two-piece reveals. Therefore, in paragraphs (j)(2)(i), (j)(3)(i), and (k)(2)(ii)(B) of the supplemental NPRM where we state that no further action is required after the replacement, the replacement is the two-piece reveal replacement specified in those paragraphs. No change is necessary for paragraphs (j)(2)(i), (j)(3)(i), and (k)(2)(ii)(B) of this supplemental NPRM in regard to this issue.

Also, for paragraphs (g)(1) and (k)(2)(i) of this supplemental NPRM, we specify to repeat inspections until a new or re-worked two-piece reveal is installed. The replacement is the two-piece reveal installation specified in those paragraphs. No change is necessary for paragraphs (g)(1) and (k)(2)(i) of this supplemental NPRM in regard to this issue.

However, we have revised paragraph (j)(1) of this supplemental NPRM for clarity as suggested by the commenter.

Request To Allow Optional Action for Material Type Inspection

Boeing requests that we allow doing a replacement with a new two-piece reveal as an optional action for the material type inspection specified in paragraph (k) of the original NPRM. Boeing states that if an existing reveal is to be reworked to a two-piece reveal, the material type inspection is necessary; however, if the reveal is replaced with a new two-piece reveal, a material type inspection is not necessary. Boeing states if an operator replaces all the reveals with new two-piece reveals, the original NPRM would still require that the material type inspection be done.

We agree to allow replacing the reveal with a new two-piece reveal as an option for the reasons stated by the commenter. In addition, we have determined it is acceptable to replace the reveal with a re-worked reveal as an option to doing the material type inspection; re-worked reveals are machined from 6061 aluminum. We have revised paragraph (k) of this supplemental NPRM accordingly.

Request To Reduce Compliance Time in Paragraph (j)(1) of the Original NPRM

Boeing requests that we reduce the compliance time “before the accumulation of another 10,000 flight cycles on the lower forward corner reveal” to “ before the accumulation of 10,000 flight cycles on the lower forward corner reveal since new (for Group 2 airplanes) or since replacement (for Group 1 Configuration 2 airplanes).” Boeing states that the first inspection should be at 1,500 flight cycles and then the interval should be 6,000 flight cycles.

We agree with the commenter that the next repeat inspection after the initial inspection done in accordance with paragraph (j) of the supplemental NPRM should be reduced. We intended to match the compliance times specified in the service bulletin but the compliance times in the service bulletin are unclear. Figure 16 of the service bulletin specifies a compliance time of “10,000 flight cycles after the reveal was last replaced” but does not refer to a compliance time of 10,000 flight cycles on the reveal since new. In addition, the commenter gives conflicting statements. The commenter's statement that the interval should be 6,000 flight cycles after the first 1,500 flight cycle inspection conflicts with its statement that the compliance time should be revised to state 10,000 flight cycles on the reveal since new or replaced. We have revised paragraph (j)(1) to reduce the compliance time as follows: Before the accumulation of 10,000 flight cycles on the lower forward corner reveal since new, or within 6,000 flight cycles after doing the inspection required by paragraph (j) of this AD, whichever occurs later.

In addition, we have revised paragraphs (g)(2)(ii), (j)(2)(ii), (j)(3)(ii), and (k)(2)(ii)(C) of the supplemental NPRM to clarify the 10,000-flight-cycle compliance time is on the replacement reveal instead of since replacement of the reveal.

Request To Revise Reference

Boeing requests that we revise the reference for doing the detailed inspection specified in paragraph (j)(1) of the original NPRM. Boeing states that instead of doing the detailed inspection as specified in paragraph (j) of the original NPRM, the paragraph should specify doing the detailed inspection in accordance with Part 5 of the service bulletin. Boeing notes that paragraph (j) refers to paragraphs (h) and (i) of the original NPRM for compliance times. Boeing contends that because paragraphs (h) and (i) include a compliance time of “before the accumulation of 1,500 total flight cycles” operators may interpret that the inspection interval is 1,500 flight cycles.

We disagree with the commenter's assertion that the compliance time interval can be interpreted as 1,500 flight cycles because the compliance time is specified in paragraph (j)(1) of the supplemental NPRM and the reference to paragraph (j) of the supplemental NPRM is for the details of how to do the inspection. However, we have revised paragraph (j)(1) of the supplemental NPRM for clarity. Although the commenter suggests pointing to Part 5 of the service bulletin for doing the inspection, Part 5 of the service bulletin refers to Part 8 of the service bulletin for doing the inspection. Therefore, we have revised paragraph (j)(1) of the supplemental NPRM to refer directly to Part 8 of the service bulletin. We have also revised paragraph (j)(1) of the supplemental NPRM to refer to paragraph (j)(3) of the supplemental NPRM for doing corrective action if any cracking is found.

In addition, we have revised paragraphs (g)(2)(ii), (j)(2)(ii), (j)(3)(ii), and (k)(2)(ii)(C) of the supplemental NPRM to clarify the references for doing the inspections.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

We are proposing this supplemental NPRM because we evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of the same type design. Certain changes described above expand the scope of the original NPRM. As a result, we have determined that it is necessary to reopen the comment period to provide additional opportunity for the public to comment on this supplemental NPRM.

Costs of Compliance

There are about 715 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this supplemental NPRM.

Estimated Costs

Action	Work hours	Average labor rate per hour	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Inspections	4	$80	$320, per inspection cycle	119	$38,080, 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
• 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-2007-29227; Directorate Identifier 2007-NM-100-AD.

Comments Due Date

(a) We must receive comments by June 16, 2008.

Affected ADs

(b) Certain requirements of this AD terminate certain requirements of AD 2007-12-11, amendment 39-15089.

Applicability

(c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, and 747SR series airplanes, certificated in any category, as identified in Boeing Special Attention Service Bulletin 747-53-2460, Revision 1, dated February 13, 2007, except airplanes that have been converted to an all-cargo configuration. The requirements of this AD also become applicable at the time when a converted airplane operating in an all-cargo configuration is converted back to a passenger or passenger/cargo configuration.

Unsafe Condition

(d) This AD results from reports of cracking and/or a sharp edge in the lower forward corner reveal of the number 3 main entry doors (MEDs). We are issuing this AD to detect and correct fatigue cracking of the lower forward corner reveal of the number 3 MEDs, which could lead to the door escape slide departing the airplane when the door is opened and the slide is deployed, and consequent injuries to passengers and crew using the door escape slide during an emergency evacuation.

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.

Service Bulletin Reference

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Boeing Special Attention Service Bulletin 747-53-2460, Revision 1, dated February 13, 2007.

Actions for Group 3 Airplanes

(g) For airplanes identified as Group 3 airplanes in the service bulletin: Before the accumulation of 10,000 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, do a detailed inspection for cracking of the lower forward corner reveals in accordance with Part 8 of the service bulletin.

(1) If no cracking is found, repeat the inspection thereafter at intervals not to exceed 6,000 flight cycles until a new or reworked two-piece reveal is installed in accordance with Part 2 of the service bulletin. No further action is required by this paragraph for that location only after the replacement.

Note 1:

For the purpose of this AD, a one-piece machined aluminum reveal may be reworked into a two-piece reveal in accordance with Part 7 of the service bulletin after it was verified to be crack free and without a sharp edge in accordance with Part 5 of the service bulletin, or after it was confirmed to be crack free in accordance with Part 5 of the service bulletin and reworked to remove a sharp edge in accordance with Part 6 of the service bulletin.

(2) If cracking is found, do the replacement specified in paragraph (g)(2)(i) or (g)(2)(ii) of this AD.

(i) Before further flight, replace the reveal with a new or reworked two-piece reveal in accordance with Part 2 of the service bulletin. No further action is required by this paragraph for that location only after the replacement.

(ii) Before further flight, replace the reveal with a new or reworked one-piece machined aluminum reveal without a sharp edge in accordance with Part 3 of the service bulletin. Before the accumulation of 10,000 flight cycles on the replacement reveal since new, do the inspection for cracking specified in Part 8 of the service bulletin and repeat the inspection thereafter at intervals not to exceed 6,000 flight cycles until a new or reworked two-piece reveal is installed in accordance with Part 2 of the service bulletin. If any cracking is found during any inspection required by this paragraph, before further flight, do the action specified in paragraph (g)(2) of this AD. No further action is required by this paragraph for that location only after the replacement with a two-piece reveal.

Note 2:

For the purpose of this AD, a one-piece machined aluminum reveal with a sharp edge may be reworked into a one-piece machined aluminum reveal without a sharp edge in accordance with Part 6 of the service bulletin after it is confirmed to be crack free in accordance with Part 5 of the service bulletin. After the sharp edge is removed, the one-piece machined aluminum reveal without a sharp edge may be further reworked into a two-piece reveal in accordance with Part 7 of the service bulletin.

Actions for Group 2 Airplanes and Group 1, Configuration 2 Airplanes

(h) For airplanes identified as Group 2 airplanes in the service bulletin: Before the accumulation of 1,500 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, do the inspection specified in paragraph (j) of this AD.

(i) For airplanes identified as Group 1, Configuration 2 airplanes in the service bulletin: Within 1,500 flight cycles after the lower forward corner reveal was last replaced or 1,000 flight cycles after the effective date of this AD, whichever occurs later, do the inspection specified in paragraph (j) of this AD.

(j) At the applicable times specified in paragraphs (h) and (i) of this AD: Do a detailed inspection of the lower forward corner reveals for cracking and a sharp edge in accordance with Part 5 of the service bulletin.

(1) If no cracking and no sharp edge are found, before the accumulation of 10,000 flight cycles on the lower forward corner reveal since new, or within 6,000 flight cycles after doing the inspection required by paragraph (j) of this AD, whichever occurs later, do the detailed inspection for cracking in accordance with Part 8 of the service bulletin and inspect thereafter at intervals not to exceed 6,000 flight cycles, until a new or reworked two-piece reveal is installed in accordance with Part 2 of the service bulletin. If any cracking is found during any inspection required by this paragraph, before further flight, do the action specified in paragraph (j)(3) of this AD. No further action is required by this paragraph for that location only after the replacement with a two-piece reveal.

(2) If no cracking is found but a sharp edge is found, do the action specified in paragraph (j)(2)(i) or (j)(2)(ii) of this AD.

(i) Before further flight, replace the lower forward corner reveal with a new or reworked two-piece reveal, in accordance with Part 2 of the service bulletin. No further action is required by this paragraph for that location only after the replacement.

(ii) Before further flight, replace the reveal with a new or reworked one-piece machined aluminum reveal without a sharp edge, in accordance with Part 3 of the service bulletin. Before the accumulation of 10,000 flight cycles on the replacement reveal since new, do the inspection for cracking in accordance with Part 8 of the service bulletin and inspect thereafter at intervals not to exceed 6,000 flight cycles, until a new or reworked two-piece reveal is installed in accordance with Part 2 of the service bulletin. If any cracking is found during any inspection required by this paragraph, before further flight, do the action required by paragraph (j)(3) of this AD. No further action is required by this paragraph for that location only after the replacement with a two-piece reveal.

(3) If cracking is found, do the action specified in paragraph (j)(3)(i) or (j)(3)(ii) of this AD.

(i) Before further flight, replace the reveal with a new or reworked two-piece reveal, in accordance with Part 2 of the service bulletin. No further action is required by this paragraph for that location only after the replacement.

(ii) Before further flight, replace the lower forward corner reveal with a new or reworked one-piece machined aluminum reveal without a sharp edge, in accordance with Part 3 of the service bulletin. Before the accumulation of 10,000 flight cycles on the replacement reveal since new, do the inspection for cracking in accordance with Part 8 of the service bulletin and inspect thereafter at intervals not to exceed 6,000 flight cycles, until a new or reworked two-piece reveal is installed in accordance with Part 2 of the service bulletin. If any cracking is found during any inspection required by this paragraph, before further flight, do the action required by paragraph (j)(3) of this AD. No further action is required by this paragraph for that location only after the replacement with a two-piece reveal.

Actions for Group 1, Configuration 1 Airplanes

(k) For airplanes identified as Group 1, Configuration 1 airplanes in the service bulletin: Before the accumulation of 1,500 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, do a material type inspection to determine if the lower forward corner reveals are castings, in accordance with the service bulletin. As an alternative to the material type inspection, replacing a reveal with a new or reworked two-piece lower forward corner reveal in accordance with Part 2 of the service bulletin is terminating action for the requirements of this paragraph for that location only.

(1) If the forward corner reveal is not a casting: Before further flight, do the actions specified in paragraph (j) of this AD except for the inspection for a sharp edge.

(2) If the forward corner reveal is a casting: Before the accumulation of 7,000 total flight cycles, within 2,000 flight cycles after the effective date of this AD, or within 3,000 flight cycles since the forward corner reveal was inspected in accordance with Boeing Service Bulletin 747-53A2378, whichever is latest, do a detailed inspection for cracking of the lower forward corner reveal, in accordance with Part 1 of Boeing Special Attention Service Bulletin 747-53-2460, Revision 1, dated February 13, 2007.

(i) If no cracking is found: Repeat the inspection specified in paragraph (k)(2) of this AD thereafter at intervals not to exceed 3,000 flight cycles until a new or reworked two-piece lower forward corner reveal is installed in accordance with Part 2 of the service bulletin. No further action is required by this paragraph for that location only after the replacement.

(ii) If cracking is found: Do the actions specified in paragraph (k)(2)(ii)(A), (k)(2)(ii)(B), or (k)(2)(ii)(C) of this AD.

(A) Before further flight, weld repair the reveal in accordance with Part 4 of the service bulletin. Repeat the inspection specified in paragraph (k)(2) of this AD thereafter at intervals not to exceed 3,000 flight cycles until a new or reworked two-piece reveal is installed in accordance with Part 2 of the service bulletin. No further action is required by this paragraph for that location only after the replacement.

(B) Before further flight, replace the reveal with a new or reworked two-piece reveal, in accordance with Part 2 of the service bulletin. No further action is required by this paragraph for that location only after the replacement.

(C) Before further flight, replace the reveal with a new or reworked one-piece machined aluminum reveal without a sharp edge, in accordance with Part 3 of the service bulletin. Before the accumulation of 10,000 flight cycles on the replacement reveal since new, do the inspection for cracking in accordance with Part 8 of the service bulletin and inspect thereafter at intervals not to exceed 6,000 flight cycles, until a new or reworked two-piece reveal is installed in accordance with Part 2 of the service bulletin. If any cracking is found during any inspection required by this paragraph, before further flight, do the action required by paragraph (k)(2)(ii)(B) or (k)(2)(ii)(C) of this AD. No further action is required by this paragraph for that location only after the replacement with a two-piece reveal.

Operator's Equivalent Procedure

(l) Although Step 5 of Figure 8 of the service bulletin specifies that operators may accomplish the actions in accordance with “an operator's equivalent procedure,” this AD requires operators to accomplish Step 5 of Figure 8 in accordance with only the procedures specified in Boeing Standard Overhaul Practices Manual (SOPM) 20-20-02 as given in the service bulletin. An “operator's equivalent procedure” may be used only if approved as an alternative method of compliance in accordance with paragraph (p) of this AD.

Compliance With AD 2007-12-11, Amendment 39-15089, for MED 3 Only

(m) Accomplishment of the applicable repair required by this AD constitutes compliance with the repair of the lower forward corner casting (reveal) of the number 3 MEDs only, as required by paragraph (q)(2)(ii) of AD 2007-12-11 (which specifies the actions be done in accordance with Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005). Accomplishment of the actions of this AD does not terminate the remaining requirements of AD 2007-12-11.

Parts Installation

(n) As of the effective date of this AD, no person may install a door lower forward corner reveal made of cast 356 aluminum on any airplane at a location specified by this AD.

(o) As of the effective date of this AD, no person may install a door lower forward corner reveal made of machined 6061 aluminum on any airplane at a location specified by this AD, unless it has been confirmed/reworked to be without a sharp edge in accordance with the service bulletin.

Alternative Methods of Compliance (AMOCs)

(p)(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) 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 appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

(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 May 7, 2008.

Michael J. Kaszycki,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.