E7-9390. Airworthiness Directives; Boeing Model 757-200 and 757-300 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 757-200 and 757-300 series airplanes. This proposed AD would require installing a copper bonding jumper between a ground and the clamp on the tube of the forward and aft gray water composite drain masts. This proposed AD results from a report of charred insulation blankets and burned wires around the forward gray water composite drain mast found during an inspection of the forward cargo compartment on a Model 767-300F airplane. We are proposing this AD to prevent a fire near a composite drain mast and possible disruption of the electrical power system due to a lightning strike on a composite drain mast, which could result in the loss of several functions essential for safe flight.

DATES:

We must receive comments on this proposed AD by July 2, 2007.

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: [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.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for the service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Dave Webber, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, 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 submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2007-28160; Directorate Identifier 2007-NM-006-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 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.

Examining the Docket

You may 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 Docket Management System receives them.

Discussion

We have received a report indicating that, during an inspection of the forward cargo compartment on a Model 767-300F airplane, an operator found charred insulation blankets and burned wires around the forward gray water composite drain mast. Additional charring on the insulation blankets was noticed several feet away along the routing of the drain mast's ground wire and power wires. Analysis of the damaged parts revealed that a lightning strike on the composite drain mast caused the damage to the wires and insulation blankets. This condition, if not corrected, could cause disruption of electrical power and fire and heat damage to equipment in the event of a lightning strike on the composite drain mast, which could result in the loss of several functions essential for safe flight.

A design review of the gray water composite drain mast installation on Model 737NG, 757, 767, and 777 airplanes revealed that the installation of a heavier bonding jumper is necessary to provide adequate lightning protection to the gray water composite drain mast installation. The subject area on Model 757 airplanes is almost identical to that on the affected Model 767-300F airplane. Therefore, Model 757 airplanes may be subject to the unsafe condition revealed on the Model 767-300F airplane. We are currently considering additional rulemaking to address the identified unsafe condition on Model 737NG, 767, and 777 airplanes.

Relevant Service Information

We have reviewed Boeing Special Attention Service Bulletin 757-30-0024, dated July 24, 2006. The service bulletin describes procedures for installing a 135-ampere copper bonding jumper between a ground and the clamp on the tube of the forward and aft gray water composite drain masts.

Above the waste-water access panel, the installation includes:

• Replacing the existing ground bracket with a new ground bracket;
• Installing a bonding jumper between the ground bracket and the clamp on the tube of the forward gray water composite drain mast;
• Doing a drain mast installation test; and
• Measuring the resistance of the bonding jumper installation.

In the bulk cargo compartment, the installation includes:

• Installing a new ground bracket;
• Installing a bonding jumper between the ground bracket and the clamp on the tube of the aft gray water composite drain mast;
• Doing a drain mast installation test; and
• Measuring the resistance of the bonding jumper installation.

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. For this reason, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously.

Costs of Compliance

There are about 83 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
Bonding jumper installation	2	$80	$353, per kit (1 kit per drain mast)	$866	59	$51,094

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 and placed it in the AD docket. 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 Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2007-28160; Directorate Identifier 2007-NM-006-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by July 2, 2007.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 757-200 and 757-300 series airplanes, certificated in any category; as identified in Boeing Special Attention Service Bulletin 757-30-0024, dated July 24, 2006.

Unsafe Condition

(d) This AD results from a report of charred insulation blankets and burned wires around the forward gray water composite drain mast found during an inspection of the forward cargo compartment on a Model 767-300F airplane. We are issuing this AD to prevent a fire near a composite drain mast and possible disruption of the electrical power system due to a lightning strike on a composite drain mast, which could result in the loss of several functions essential for safe flight.

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.

Bonding Jumper Installation

(f) Within 60 months after the effective date of this AD: Install a 135-ampere copper bonding jumper between a ground and the clamp on the tube of the forward and aft gray water composite drain mast, in accordance with the Accomplishment instructions of Boeing Special Attention Service Bulletin 757-30-0024, dated July 24, 2006.

Alternative Methods of Compliance (AMOCs)

(g)(1) The Manager, Seattle Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Issued in Renton, Washington, on May 7, 2007.

Stephen P. Boyd,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.