05-8761. Airworthiness Directives; Boeing Model 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 adopt a new airworthiness directive (AD) for certain Boeing Model 747-400 and 747-400D series airplanes. This proposed AD would require an inspection for corrosion and cracks of the station 980 upper deck floor beam, and repair and related investigative actions if necessary. This proposed AD is prompted by reports of corrosion under the cart lift threshold at the station 980 upper deck floor beam. We are proposing this AD to detect and correct such corrosion, which could result in a cracked or broken floor beam, extensive damage to adjacent structure, and possible rapid decompression of the airplane.

DATES:

We must receive comments on this proposed AD by June 17, 2005.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, Washington, DC 20590.
• By fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street SW., Washington, DC, 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, P.O. Box 3707, Seattle, Washington 98124-2207.

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2005-21088; the directorate identifier for this docket is 2004-NM-267-AD.

FOR FURTHER INFORMATION CONTACT:

Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2005-21088; Directorate Identifier 2004-NM-267-AD” in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments submitted by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You can review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

Examining the Docket

You can examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the DMS receives them.

Related Rulemaking

Corrosion of the station 980 upper deck floor beam was addressed in AD 97-09-13, amendment 39-10009 (62 FR 24022, May 2, 1997). That AD requires inspecting the station 980 upper deck floor beam and installing sealant under the threshold in accordance with Boeing Alert Service Bulletin 747-53A2400, dated December 21, 1995. AD 97-09-13 applies to certain Model 747 series airplanes.

Discussion

Beginning with line number 844, a production change was made at the cart lift cutout in the upper deck floor to increase the durability of the station 980 floor beam and to add sealant between the floor beam and the threshold. Recent reports have shown that a corrosion problem also exists in the new configuration under the cart lift threshold. Corrosion of the floor structure occurred where the stainless steel threshold contacts the aluminum floor structure. Such corrosion could result in a cracked or broken floor beam, extensive damage to adjacent structure, and possible rapid decompression of the airplane.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-53A2503, dated November 11, 2004. The service bulletin describes procedures for inspecting the station 980 upper deck floor beam for corrosion and cracks, and repairing corrosion. The service bulletin specifies contacting Boeing for repair instructions for any cracks and for corrosion that exceeds the specified limits. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. Therefore, we are proposing this AD, which 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 that you may contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require you to repair those conditions by using either a method that we approve or data that meet the certification basis of the airplane and have been approved by an Authorized Representative for the Boeing Delegation Option Authorization Organization whom we have authorized to make those findings.

The service bulletin specifies an inspection threshold of 10 years after the initial date of delivery of the airplane. However, paragraph (f)(1) of this proposed AD specifies an inspection threshold of 120 months after the date of issuance of the original Airworthiness Certificate or the date of issuance of the original Export Certificate of Airworthiness. This decision is based on our determination that “date of delivery” may be interpreted differently by different operators. We find that our proposed terminology is generally understood within the industry and records will always exist that establish these dates with certainty.

The service bulletin specifies a “detailed visual inspection.” We have determined that the proposed inspection should be considered a “detailed inspection.” However, we consider the inspection definition in the service bulletin to be adequate.

Costs of Compliance

There are about 363 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Inspection	3	$65	None required	$195	46	$8,970

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. 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
• 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 airworthiness directive (AD):

Boeing: Docket No. FAA-2005-21088; Directorate Identifier 2004-NM-267-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by June 17, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 747-400 and 747-400D series airplanes, certificated in any category, as listed in Boeing Alert Service Bulletin 747-53A2503, dated November 11, 2004.

Unsafe Condition

(d) This AD was prompted by reports of corrosion under the cart lift threshold at the station 980 upper deck floor beam. We are issuing this AD to detect and correct such corrosion, which could result in a cracked or broken floor beam, extensive damage to adjacent structure, and possible rapid decompression of the airplane.

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.

Inspection

(f) At the later of the times specified in paragraphs (f)(1) and (f)(2) of this AD: Do a detailed inspection for corrosion and cracks of the station 980 upper deck floor beam, in accordance with Boeing Alert Service Bulletin 747-53A2503, dated November 11, 2004.

(1) Inspect within 120 months since the date of issuance of the original Airworthiness Certificate or the date of issuance of the original Export Certificate of Airworthiness; or

(2) Inspect at the time specified in paragraph (f)(2)(i), (f)(2)(ii), or (f)(3)(iii) of this AD for the applicable airplane group as identified in the service bulletin.

(i) For Group 1 airplanes: Within 18 months after the effective date of this AD.

(ii) For Group 2 airplanes: Within 36 months after the effective date of this AD.

(iii) For Group 3 airplanes: Within 120 months after the airplane has been modified in accordance with Boeing Service Bulletin 747-25-3107, or within 36 months after the effective date of this AD, whichever occurs later.

Repair

(g) If any cracking or corrosion is found during any inspection required by this AD, do all related investigative and corrective actions before further flight in accordance with Boeing Alert Service Bulletin 747-53A2503, dated November 11, 2004. If the bulletin specifies to contact Boeing for appropriate action, repair before further flight according to a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or according to data meeting the certification basis of the airplane approved by an Authorized Representative for the Boeing 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 approval must specifically reference this AD.

Alternative Methods of Compliance (AMOCs)

(h)(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) 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 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 approval must specifically refer to this AD.

Issued in Renton, Washington, on April 21, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.