E9-3614. Airworthiness Directives; Boeing Model 747 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 all Boeing Model 747 airplanes. The original NPRM would have required inspecting for cracks in the left- and right-side Stringer 11 longeron adjacent to the horizontal stabilizer pivot bulkhead, and related investigative and corrective actions if necessary. The original NPRM resulted from a report of a crack found in the right-side Stringer 11 longeron horizontal flange, adjacent to the horizontal stabilizer pivot bulkhead, during a routine maintenance inspection. This action revises the original NPRM by reducing the compliance times for certain airplanes. We are proposing this supplemental NPRM to detect and correct fatigue cracking of the longeron, which can propagate and cause damage to the adjacent horizontal stabilizer pivot bulkhead. This damage could result in loss of structural integrity and consequent inability of the bulkhead to carry flight loads, which could adversely affect controllability of the airplane.

DATES:

We must receive comments on this supplemental NPRM by March 17, 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 AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207; telephone [phone]; 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-2008-0612; Directorate Identifier 2008-NM-059-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 all Boeing Model 747 airplanes. That original NPRM was published in the Federal Register on June 6, 2008 (73 FR 32246). That original NPRM proposed to require inspecting for cracks in the left- and right-side Stringer 11 longeron adjacent to the horizontal stabilizer pivot bulkhead, and related investigative and corrective actions if necessary.

Actions Since Original NPRM Was Issued

Since we issued the original NPRM, we have reviewed Boeing Service Bulletin 747-53A2703, Revision 1, dated September 16, 2008. We referred to Boeing Alert Service Bulletin 747-53A2703, dated February 14, 2008, as the appropriate source of service information for accomplishing the actions specified in the original NPRM. Revision 1 of Boeing Service Bulletin 747-53A2703 is essentially the same as Boeing Alert Service Bulletin 747-53A2703, dated February 14, 2008. However, the compliance times have been reduced for Model 747-400 series airplanes that are converted to the Model 747-400 large cargo freighter (LCF) configuration in Boeing Service Bulletin 747-53A2703, Revision 1, dated September 16, 2008. Boeing analysis shows that airplanes converted to a Model 747-400LCF configuration have increased structural loads. Those airplanes have been moved from Group 1 to new Groups 2 or 3.

The reduced compliance times for the inspections are as follows:

• For Group 2 airplanes: Before the accumulation of 16,000 total flight cycles, or within 1,500 flight cycles after the date on the service bulletin, whichever occurs later.
• For Group 3 airplanes: Before the accumulation of 13,500 total flight cycles, or within 1,500 flight cycles after the date on the service bulletin, whichever occurs later.

The repetitive interval has been reduced to 2,000 flight cycles.

Comment

We gave the public the opportunity to participate in developing this AD. We considered the comment received.

Request To Increase Work Hours in Costs of Compliance Section

Northwest Airlines (NWA) asks that we increase the work hours specified in the Costs of Compliance section in the original NPRM. NWA states that the estimate of 3 work hours per airplane, as specified in the original NPRM, does not match the work-hour estimate specified in Boeing Alert Service Bulletin 747-53A2703, dated February 14, 2008. NWA notes that Boeing Alert Service Bulletin 747-53A2703 specifies 6 work hours per airplane are necessary to accomplish the recommended inspections.

We do not agree to increase the work-hour estimate specified in the original NPRM. The required action in the original NPRM is doing a surface high frequency eddy current (HFEC) inspection; the open hole HFEC inspection is an on-condition action (related investigative and corrective actions) and might not be necessary, depending on the findings. We recognize that, in doing the actions required by an AD, operators might incur incidental costs in addition to the direct costs. The cost analysis in AD rulemaking actions, however, typically does not include incidental costs such as the time required to gain access and close up, time necessary for planning, or time necessitated by other administrative actions. Those incidental costs, which might vary significantly among operators, are almost impossible to calculate. We also typically do not include the cost of on-condition actions, although we recognize that doing the on-condition actions imposes additional operational costs. We have not changed the AD in this regard.

Explanation of Change to the Original NPRM

We have added a new paragraph (d) to this supplemental NPRM which includes the Air Transport Association of America (ATA) code, and we have reidentified subsequent paragraphs accordingly.

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. The change in compliance times described above expands 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

We estimate that this proposed AD would affect 165 airplanes of U.S. registry. We also estimate that it would take 3 work-hours per product to comply with this proposed AD. The average labor rate is $80 per work-hour. Based on these figures, we estimate the cost of this proposed AD to the U.S. operators to be $39,600, or $240 per product.

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-2008-0612; Directorate Identifier 2008-NM-059-AD.

Comments Due Date

(a) We must receive comments by March 17, 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 a report of a crack found in the right-side Stringer 11 longeron horizontal flange, adjacent to the horizontal stabilizer pivot bulkhead, during a routine maintenance inspection. We are issuing this AD to detect and correct fatigue cracking of the longeron, which can propagate and cause damage to the adjacent horizontal stabilizer pivot bulkhead. This damage could result in loss of structural integrity and consequent inability of the bulkhead to carry flight loads, which could adversely affect controllability of the airplane.

Compliance

(f) Comply with this AD within the compliance times specified, unless already done.

Inspection/Related Investigative and Corrective Actions

(g) Except as provided by paragraph (h) of this AD: At the applicable times specified in paragraph 1.E. of Boeing Service Bulletin 747-53A2703, Revision 1, dated September 16, 2008, do a surface high frequency eddy current (HFEC) inspection for cracks in the left- and right-side Stringer 11 longeron exposed surfaces and edges between Station 2598 and 2607 adjacent to the horizontal stabilizer pivot bulkhead; and do all applicable related investigative and corrective actions before further flight, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53A2703, Revision 1, dated September 16, 2008, except as provided by paragraph (h) of this AD.

Exception to Compliance Times

(h) Where Boeing Service Bulletin 747-53A2703, Revision 1, dated September 16, 2008, specifies counting the compliance time from “* * * the date on this service bulletin,” this AD requires counting the compliance time from the effective date of this AD.

Exception to Corrective Actions

(i) If any crack is found during any inspection required by this AD, and Boeing Service Bulletin 747-53A2703, Revision 1, dated September 16, 2008, specifies to contact Boeing for appropriate action: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (j) of this AD.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, ATTN: Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone] has the authority to approve AMOCs for this AD, if requested using 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 principal maintenance inspector (PMI) or principal avionics inspector (PAI), 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 January 30, 2009.

Stephen P. Boyd,

Assistant Manager, Transport Airplane Directorate, Aircraft Certification Service.