E8-25636. Airworthiness Directives; Boeing Model 757-200 and 757-300 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

We are adopting a new airworthiness directive (AD) for certain Boeing Model 757-200 and 757-300 series airplanes. This AD requires installing a bonding jumper between a ground and the clamp on the tube of the forward and aft gray water composite drain masts. For certain airplanes, this AD requires inspecting existing aft bonding jumper assemblies that might be too short, repair if necessary, and replacing the bonding jumper assembly with a new, longer bonding jumper assembly if necessary. 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.

DATES:

This AD is effective December 17, 2008.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of December 17, 2008.

ADDRESSES:

For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207; telephone [phone]; fax [phone]; e-mail [e-mail]; Internet https://www.myboeingfleet.com.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The address for the Docket Office (telephone [phone]) is the Document Management Facility, U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT:

Nicholas Wilson, 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:

Discussion

We issued a supplemental notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to certain Boeing Model 757-200 and 757-300 series airplanes. That supplemental NPRM was published in the Federal Register on April 8, 2008 (73 FR 19015). That supplemental NPRM proposed to require installing a bonding jumper between a ground and the clamp on the tube of the forward and aft gray water composite drain masts. For certain airplanes, that supplemental NPRM also proposed to require inspecting existing aft bonding jumper assemblies that might be too short, repair if necessary, and replacing the bonding jumper assembly with a new, longer bonding jumper assembly if necessary.

Comments

We gave the public the opportunity to participate in developing this AD. We considered the comments received.

Support for the AD

Boeing concurs with the contents of the supplemental NPRM. Continental Airlines has no objection to the supplemental NPRM. Northwest Airlines (NWA) is in general concurrence with the modification requirements and concurs with the 60-month compliance time. The Air Transport Association (ATA), on behalf of member airlines, states that its members agree with the intent of the NPRM.

Request To Have Service Information Revised

American Airlines (AAL) requests that Boeing Special Attention Service Bulletin 757-30-0024, Revision 1, dated October 25, 2007, be revised to change the pilot hole dimensions in Figure 2, Sheet 2. (We referred to Boeing Special Attention Service Bulletin 757-30-0024, Revision 1, dated October 25, 2007, as the appropriate source of service information for the proposed actions in the NPRM.) AAL points out that the new bracket is provided without pilot holes, but the service bulletin specifies the hole location: “Tolerance on linear dimensions, other than rivet and bolt edge margins, is plus or minus 0.03 inch.” AAL is concerned that it may be an unreasonable expectation, within the on-aircraft environment in which the work is being performed, to locate the holes in the bracket to within 0.03 inch of the specified location. Therefore, AAL recommends that the service bulletin be revised to change the hole location dimensions to be “0.43 minimum.” As a supporting argument for this change, AAL points out that the new grounding bracket is installed in a different location to meet the same intent for the forward drain mast and does not include dimensional location information, which AAL believes implies that the hole location in the bracket is not critical to meeting the intent of the service bulletin.

While we do agree that the on-airplane environment can sometimes be a difficult place to work, we disagree that the service bulletin should be revised as requested by AAL. Boeing has pointed out that the edge margin requirement for the fasteners on the bonding bracket is not as critical as the placement of the fastener through stringer S-25 right. This fastener location must be drilled to within 0.35 inch, plus or minus 0.03 inch, from the top edge of the stringer on the airplane. If it is possible to maintain this drawing requirement for on-airplane installation, it should also be possible to maintain the edge margin requirements for the bonding bracket. We have confirmed that Boeing has no plans to revise the service bulletin to change the pilot hole dimensions in Figure 2, Sheet 2. We have not changed the AD in this regard.

Request To Revise the Costs of Compliance

The ATA, on behalf of NWA, requests that we revise the proposed Costs of Compliance provided in the supplemental NPRM. NWA states that Boeing Special Attention Service Bulletin 757-30-0024, Revision 1, dated October 25, 2007, estimates 5.35 work-hours to do the proposed modification. NWA considers this estimate to be low because of the limited access to the area to be modified. Further, NWA notes that the cost estimate provided in the supplemental NPRM reduced the work-hour estimate to only 2 work-hours. Therefore, NWA believes that we have underestimated the costs of compliance imposed on operators.

We do not agree to revise the proposed work-hour estimate. The work-hour estimate of 5.35 pointed out by NWA includes time necessary for access and close. The cost information below describes only the direct costs of the specific actions required by this AD. Based on the best data available, the manufacturer provided the number of work-hours (2) necessary to do the required actions. This number represents the time necessary to perform only the actions actually required by this AD.

We recognize that, in doing the actions required by an AD, operators might incur incidental costs in addition to the direct costs. The cost analysis in AD rulemaking actions, however, typically does not include incidental costs such as the time required to gain access and close up, time necessary for planning, or time necessitated by other administrative actions. Those incidental costs, which might vary significantly among operators, are almost impossible to calculate. We have not changed the AD in this regard.

Conclusion

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD as proposed.

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 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	1 392	944	70	66,080
Inspection of existing bonding jumper installation in bulk cargo compartment	1	80	392	472	Up to 70	Up to 33,040
1 Per kit (1 kit per drain mast).

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

This AD will not have federalism implications under Executive Order 13132. This AD will 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 this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Is not a “significant rule” under 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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 AD:

2008-22-08 Boeing: Amendment 39-15703. Docket No. FAA-2007-28160; Directorate Identifier 2007-NM-006-AD.

Effective Date

(a) This airworthiness directive (AD) is effective December 17, 2008.

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, Revision 1, dated October 25, 2007.

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) Except as provided by paragraph (g) of this AD: Within 60 months after the effective date of this AD, install a bonding jumper between a ground and the clamp on the tube of the forward and aft gray water composite drain mast, in accordance with Parts 1 and 2 of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-30-0024, Revision 1, dated October 25, 2007.

Existing Bonding Jumper Inspection

(g) For airplanes on which the bonding jumper was installed on the aft drain mast in accordance with Boeing Special Attention Service Bulletin 757-30-0024, dated July 24, 2006: Within 60 months after the effective date of this AD, do a general visual inspection of the aft bonding jumper assembly for signs of riding (chafing), in accordance with Part 3 of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-30-0024, Revision 1, dated October 25, 2007 (“the service bulletin”). If no riding damage is found, no further action is required by this AD for the aft drain mast. If riding damage is found, before further flight do the actions specified in paragraphs (g)(1) and (g)(2) of this AD. Doing the actions specified in this paragraph terminates the requirement to install the bonding jumper on the aft drain mast specified in paragraph (f) of this AD.

(1) Repair any riding damage found in accordance with the service bulletin.

(2) Remove the existing bonding jumper assembly and install a new, longer bonding jumper assembly in accordance with Part 3 of the Accomplishment Instructions of the service bulletin. As an option to the longer bonding jumper assembly, operators may remove the bracket, fill the holes in the stringer, and restore the finish in accordance with Part 3 of the Accomplishment Instructions of the service bulletin; and install the ground bracket and jumper assembly in accordance with Part 2 of the Accomplishment Instructions of the service bulletin.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, ATTN: Nicholas Wilson, 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]; has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

Material Incorporated by Reference

(i) You must use Boeing Special Attention Service Bulletin 757-30-0024, Revision 1, dated October 25, 2007, to do the actions required by this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207; telephone [phone]; fax [phone]; e-mail [e-mail]; Internet https://www.myboeingfleet.com.

(3) You may review copies of the service information incorporated by reference at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

Issued in Renton, Washington, on October 10, 2008.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.