Airworthiness Directives; Boeing Model 767 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 767 series airplanes. This proposed AD would require performing a test of the bonding resistance between the engine fuel feed tube fitting and the front spar, applying sealant on a hex nut inside the dry bay, and performing any applicable corrective actions. This proposed AD is prompted by a report that the engine fuel feed tubes were found not electrically bonded to the front spar. We are proposing this AD to prevent an ignition source from entering the fuel tank during a lightning strike event, which could cause a fuel tank explosion.

DATES:

We must receive comments on this proposed AD by January 10, 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: (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: Bernie Gonzalez, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6498; 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 written relevant data, views, or arguments regarding this proposed AD. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2004-19680; Directorate Identifier 2003-NM-215-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 website, 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 .

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 in person at the Docket Management Facility office between 9:00 a.m. and 5:00 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

We have received a report that, during electrical bonding and grounding tests of penetrations on the wing fuel tanks of Boeing Model 747 series airplanes, the feed tubes for the engine fuel were found not electrically bonded to the front spar. The same condition was found on Model 767 series airplanes; Model 737-100, -200, -200C, -300, -400, and -500 series airplanes; and Model 707 series airplanes. This condition, if not corrected, could result in an ignition source entering the fuel tank during a lightning strike event, which could cause a fuel tank explosion.

Other Relevant Rulemaking

We previously issued AD 2004-10-06, amendment 39-13636 (69 FR 28046, May 18, 2004), applicable to Model 747 series airplanes; Model 737-100, -200, -200C, -300, -400, and -500 series airplanes; and Model 727-100, and -200 series airplanes. That AD was issued to ensure that the similar unsafe condition (hydraulic heat exchanger tube penetration fittings were found not electrically bonded to the fuel tank rear spar) was repaired. That AD requires, among other things, preparation of the electrical bonding faying surfaces for the tubing penetrations of the hydraulic heat exchanger on the forward and aft surfaces of the rear spars of the fuel tanks of the left and right wings, a one-time measurement of the electrical bonding resistances, and follow-on actions.

We have also published a proposal to amend 14 CFR Part 39 with an AD for certain Boeing Model 707-100, -100B, -300, -300B (-320B variant), -300C, and -E3A (military) series airplanes; Model 720, and 720B series airplanes; Model 737-100, -200, -200C, -300, -400, and -500 series airplanes; and Model 747 series airplanes in the Federal Register on August 4, 2004 (69 FR 47031). That action proposed to require repetitive tests of the overwing fuel fill ports for certain wing tanks; an electrial bonding resistance test between the bulkhead fittings of the engine fuel feed tube and the front spar inside the fuel tank of the wings; other specified actions; and applicable corrective actions if necessary.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletins 767-28A0071, Revision 1 (for Model 767-200, -300, and -300F series airplanes), and 767-28A0072, Revision 1 (for Model 767-400ER series airplanes); both dated January 22, 2004. These service bulletins describe procedures for doing a test to determine the bonding resistance between the engine fuel feed tube fitting and the front spar, applying sealant on a hex nut inside the dry bay, and doing corrective actions if necessary. The corrective actions include applying sealant inside and outside the fuel tube bulkhead fitting and coupling, reworking the bonding path, and checking the fuel feed tubes for leaks. Accomplishment of the actions specified in the applicable service bulletin is intended to adequately address the identified 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 performing a test of the bonding resistance between the engine fuel feed tube fitting and the front spar, applying sealant on a hex nut inside the dry bay, and performing any applicable corrective actions. The proposed AD would require you to use the service information described previously to perform these actions.

Costs of Compliance

There are about 867 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 400 airplanes of U.S. registry. The proposed actions would take about 3 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $78,000, or $195 per airplane.

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.