04-17989. Airworthiness Directives; Boeing Model 747-400 and -400F Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), 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 -400F series airplanes. This proposed AD would require a detailed inspection(s) for cracks and fractures of the side guide support fittings in the lower lobe cargo compartments; and applicable investigative/corrective actions and operational limitations, if necessary. This proposed AD also would require a terminating action for the repetitive inspections. This proposed AD is prompted by reports of cracked/fractured side guide support fittings in the aft, lower lobe cargo compartment. We are proposing this AD to prevent cracked/fractured side guide support fittings in the lower lobe cargo compartments, which could result in unrestrained cargo shifting in flight and damaging the airplane structure or systems, and consequent reduced controllability of the airplane.

DATES:

We must receive comments on this proposed AD by September 20, 2004.

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.

You can get the service information identified in this proposed AD from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

You may examine the contents of this AD docket on the Internet at http://dms.dot.gov,, or 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.

FOR FURTHER INFORMATION CONTACT:

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

SUPPLEMENTARY INFORMATION:

Docket Management System (DMS)

The FAA has implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, new AD actions are posted on DMS and assigned a docket number. We track each action and assign a corresponding directorate identifier. The DMS AD docket number is in the form “Docket No. FAA-2004-99999.” The Transport Airplane Directorate identifier is in the form “Directorate Identifier 2004-NM-999-AD.” Each DMS AD docket also lists the directorate identifier (“Old Docket Number”) as a cross-reference for searching purposes.

Comments Invited

We invite you to submit any written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2004-18728; Directorate Identifier 2003-NM-176-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 may review DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications that affect you. You can get more information about plain language at http://www.faa.gov/​language and http://www.plainlanguage.gov.

Examining the Docket

You may examine the AD docket 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.

Discussion

We have received two reports indicating that cracked/fractured side guide support fittings were found in the aft, lower lobe cargo compartment on Boeing Model 747-400F series airplanes that had been in service less than 16 months. One airplane had a total of 16 cracked/fractured side guide support fittings and the other airplane had 4. The side guide support fittings provide lateral and vertical restraint for cargo in the lower lobe cargo compartments.

Investigation revealed that failed roller assemblies in the outboard roller trays caused the conveyor plane of the unit load device (ULD) to drop and allowed the ULD to impact the side guide support fittings. Repeated impacts by the ULD can result in fatigue and consequent cracked/fractured side guide support fittings. The roller assembly failures were caused by a manufacturing defect in the bearings that resulted in the separation of the bearing's inner and outer race.

Cracked/fractured side guide support fittings in the lower lobe cargo compartments, if not corrected, could result in unrestrained cargo shifting in flight and damaging the airplane structure or systems and consequent reduced controllability of the airplane.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-25A3335, dated July 3, 2003. The service bulletin describes procedures for a detailed inspection(s) for cracks and fractures of the side guide support fittings in the lower lobe cargo compartments, and applicable investigative/corrective actions and operational limitations, if necessary. The applicable investigative actions include a general visual inspection of the cargo compartment for damage, and repair if necessary. The corrective actions include replacing cracked or fractured side guide support fittings with new fittings; and replacing all outboard roller assemblies with new assemblies, which would eliminate the need for repetitive detailed inspections. The service bulletin also describes operational limitations for missing restraints until replacement of cracked or fractured side guide support fittings. We have determined that accomplishing of the actions specified in the service bulletin will adequately address the unsafe condition.

Boeing Alert Service Bulletin 747-25A3335 refers to Goodrich Alert Service Bulletin 65B60176-25-A01, dated March 3, 2003, as an additional source of service information for doing the replacement of the outboard roller assemblies.

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 a detailed inspection(s) of the side guide support fittings in the lower lobe cargo compartments for cracks and fractures; and applicable investigative/corrective actions and operational limitations, if necessary. This proposed AD also would require a terminating action for the repetitive inspections. The proposed AD would require you to use the service information described previously to perform these actions, except as discussed under “Difference Between the Proposed AD and Service Bulletin.”

Difference Between the Proposed AD and Service Bulletin

Figures 1 and 2 of the referenced Boeing service bulletin specify a general visual inspection of the cargo compartment for damage, and repair if necessary. We have determined that those actions are not necessary to adequately address the identified unsafe condition of this AD. Therefore, this proposed AD would not require operators to do that inspection and repair.

Costs of Compliance

This proposed AD would affect about 22 airplanes worldwide. 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, per inspection cycle	5	$65	None	$325*	3	$975*
Assembly replacement	25	$65	$3,402	$5,027	3	$15,081
* Per inspection cycle.

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-2004-18728; Directorate Identifier 2003-NM-176-AD.

Comments Due Date

(a) The Federal Aviation Administration (FAA) must receive comments on this AD action by September 20, 2004.

Affected ADs

(b) None.

Applicability: (c) This AD applies to Boeing Model 747-400 and “400F series airplanes, certificated in any category; as listed in Boeing Alert Service Bulletin 747-25A3335, dated July 3, 2003.

Unsafe Condition

(d) This AD was prompted by reports of cracked/fractured side guide support fittings in the aft, lower lobe cargo compartment. We are issuing this AD to prevent cracked/fractured side guide support fittings in the lower lobe cargo compartments, which could result in unrestrained cargo shifting in flight and damaging the airplane structure or systems, and consequent reduced controllability 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, Investigative/Corrective Actions, and Operational Limitations

(f) At the applicable time(s) specified in Table 1 of this AD, do a detailed inspection(s) of the side guide support fittings in the lower lobe cargo compartments for cracks and fractures, and before further flight, do all applicable investigative/corrective actions and operational limitations, if necessary, by accomplishing all the actions specified in Work Package 1 and Work Package 2 of the Work Instructions of Boeing Alert Service Bulletin 747-25A3335, dated July 3, 2003; except as required by paragraph (g) of this AD. Replacement of all outboard roller assemblies with new assemblies in accordance with Work Package 2 of the service bulletin ends the repetitive inspections required by paragraph (f)(1) of this AD (Work Package 1).

Table 1.—Compliance Times

For—	Initial compliance time—	Repetitive interval—
(1) Work Package 1	Within 180 days after the effective date of this AD	At intervals not to exceed 180 days, until all outboard roller assemblies have been replaced per Work Package 2 of the service bulletin.
(2) Work Package 2	Within 18 months after the effective date of this AD	None.

Note 1:

For the purposes of this AD, a detailed inspection is “an intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors magnifying lenses, etc. may be necessary. Surface cleaning and elaborate procedures may be required.”

Note 2:

Boeing Alert Service Bulletin 747-25A3335 refers to Goodrich Alert Service Bulletin 65B60176-25-A01, dated March 3, 2003, as an additional source of service information for replacing the outboard roller assemblies.

Alternative Methods of Compliance (AMOCs)

(g) The Manager, Seattle ACO, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

Issued in Renton, Washington, on July 29, 2004.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.