Airworthiness Directives; Boeing Model 747, 757, 767 and 777 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) for certain Boeing Model 747, 757, 767, and 777 series airplanes. That AD currently requires modifying certain drip shields located on the flight deck, and follow-on actions. This proposed AD would remove certain airplanes that are included in the applicability statement of the existing AD, and would require modifying additional drip shields on the flight deck of certain other airplanes. This proposed AD is prompted by a determination that certain airplanes have drip shields that are not adequately resistant to fire. We are proposing this AD to prevent potential ignition of the moisture barrier cover of the drip shield, which could propagate a small fire that results from an electrical arc, leading to a larger fire.

DATES:

We must receive comments on this proposed AD by January 31, 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.
• Fax: (202) 493-2251.
• 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 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:

Technical information: Patrick Gillespie, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6429; fax (425) 917-6590.

Plain language information: Marcia Walters, marcia.walters@faa.gov.

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 relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2004-19865; Directorate Identifier 2003-NM-242-AD” at the beginning 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 received 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 our docket 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 the 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.

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 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 (800) 647-5227) 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

On December 20, 2000, we issued AD 2000-26-04, amendment 39-12054 (65 FR 82901, December 29, 2000), for certain Boeing Model 747, 757, 767, and 777 series airplanes. That AD requires modification of certain drip shields located on the flight deck, and follow-on actions. That AD was prompted by a report that, on certain Boeing Model 747, 757, 767, and 777 series airplanes, the airplane manufacturer found some drip shields assembled with the moisture barrier cover bonded to the insulation and multiple insulation layers bonded together using a non-flame-resistant adhesive. We issued that AD to prevent potential ignition of the moisture barrier cover of the drip shield, which could propagate a small fire that results from an electrical arc, leading to a larger fire.

Actions Since Existing AD Was Issued

Since we issued AD 2000-26-04, the airplane manufacturer has determined that additional Model 757-200, -200CB, and -200PF series airplanes in certain configurations have drip shields that were not fire-blocked from potential ignition sources.

Also, the airplane manufacturer has sampled and tested drip shield material on certain Model 747 and 767 series airplanes, and has determined that airplanes within certain line number ranges have compliant drip shields. Neither further testing nor installation of fire blocks is necessary on airplanes within these line number ranges. As a result, we estimate that approximately 550 Model 747 series airplanes and 470 Model 767 series airplanes, worldwide, will no longer be subject to the existing requirements.

Relevant Service Information

We have reviewed Boeing Service Bulletin 757-25-0226, Revision 3, dated September 2, 2004. (AD 2000-26-04 refers to the original issue of that service bulletin, dated July 3, 2000, as the acceptable source of service information for doing the required actions on certain Model 757-200, -200CB, and -200PF series airplanes.) Revision 3 of the service bulletin describes procedures for modifying certain drip shields on the flight deck by installing fire blocks in areas where the drip shield is exposed to potential ignition sources. The procedures in Revision 3 of the service bulletin are substantially similar to those in Revision 2 of the service bulletin, dated October 31, 2002. However, Revision 2 differs from the original issue of the service bulletin in that Revision 2 adds procedures for installing fire blocks above windows number 2 and 3 on the flight deck on certain airplanes. Revision 2 also clarifies certain other procedures and corrects a part number of a washer that is used with a rivet to attach fire blocks to the drip shields. We have determined that accomplishment of the actions specified in Revision 3 of the service information will adequately address the unsafe condition.

We have also reviewed Boeing Service Bulletins 747-25-3253, Revision 3, dated September 4, 2003; and 767-25-0290, Revision 4, dated October 28, 2004. (AD 2000-26-04 refers to the original issues of these service bulletins, both dated June 29, 2000, as the acceptable sources of service information for doing the required actions on affected Model 747 and 767 series airplanes.) Service bulletins 747-25-3253, Revision 3, and 767-25-0290, Revision 4, describe procedures that are similar to those in the original issue of those service bulletins. The latest revisions include a revised effectivity listing (but don't add any airplanes on which work is required) and clarify certain procedures.

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 products of this same type design. Therefore, we are proposing this AD, which would supersede AD 2000-26-04. This proposed AD would continue to require modifying certain drip shields on the flight deck, and related investigative and other specified actions. This proposed AD would remove certain Model 747 and Model 767 series airplanes from the applicability statement, and would require modifying additional drip shields on the flight deck on certain Model 757-200, -200CB, and -200PF series airplanes. This 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 Information.”

Difference Between the Proposed AD and Service Information

We have revised the applicability stated in paragraph (c) of this proposed AD to state that the requirements of this AD apply to Model 747 series airplanes having line numbers (L/Ns) 1 through 299 inclusive and 951 through 1234 inclusive (except L/Ns 292, 296, 297, 1174, and 1216), and Model 767 series airplanes having L/Ns 470 through 768 (except L/N 758). This applicability doesn't directly correspond to the effectivity listing of Boeing Service Bulletins 747-25-3253, Revision 3, and 767-25-0290, Revision 4. Those service bulletins state that no action is necessary on airplanes in Group 3 of Boeing Service Bulletin 747-25-3253, Revision 3, and in Group 1 of Boeing Service Bulletin 767-25-0290, Revision 4. However, instructions for airplanes in those groups have been included in the service bulletin for the convenience of affected operators, so those airplanes are included in the effectivity listing. Because no action is necessary for those airplanes, we have removed the airplanes in those groups from the applicability stated in paragraph (c) of this AD.

Changes to Existing AD

This proposed AD would retain all requirements of AD 2000-26-04. Since AD 2000-26-04 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Also, we have revised the “Optional Sampling” provision in paragraph (h) of this AD. We changed the service bulletin reference for Model 747 series airplanes from the original issue to Revision 3 of Boeing Service Bulletins 747-25-3253. As explained under “Difference Between the Proposed AD and Service Information,” Boeing has moved certain airplanes on which no action is necessary from Group 1 to Group 3 in Revision 3 of the service bulletin. We have also removed the reference to Model 767 series airplanes listed in Group 1 of Boeing Service Bulletin 767-25-0290. Boeing doesn't need any more sampling data from these airplanes.

Costs of Compliance

This proposed AD would affect about 2,222 airplanes worldwide. The following table provides the estimated costs for U.S. operators to comply with the actions that are required by AD 2000-26-04 and retained in this proposed AD. The average labor rate is $65 per work hour.

For Model 747 series airplanes listed in Group 1 in Boeing Service Bulletin 747-25-3253, Revision 3, in lieu of doing the modification of the drip shields, this proposed AD provides an option to take samples of the drip shields to determine if the modification is necessary. Therefore, the estimated costs above may be reduced if some airplanes do not need the modification. It would take approximately 18 work hours to do the sampling, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of the sampling is estimated to be $1,170 per sampled airplane.

As many as 491 U.S.-registered Model 757-200, -200CB, and -200PF series airplanes may be subject to the new proposed actions. These new actions would take about 8 additional work hours per airplane, at an average labor rate of $65 per work hour. Required parts would cost an additional $160 per airplane (for a total parts cost of $1,860). Based on these figures, the estimated cost of the new actions specified in this proposed AD for U.S. operators of affected airplanes is up to an additional $333,880 or $680 per airplane.

Authority for This Rulemaking

The FAA's authority to issue rules regarding aviation safety is found in Title 49 of the United States Code. 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.

This rulemaking is promulgated under the authority described in subtitle VII, part A, subpart III, section 44701, “General requirements.” Under that section, the FAA is charged with promoting safety 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 proposed AD.

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.