E6-16199. Airworthiness Directives; McDonnell Douglas Model 717-200 Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for certain McDonnell Douglas Model 717-200 airplanes. This AD requires replacing the lightning critical clamp bases of the fuel tank vent system with improved clamp bases; and checking the electrical bond of the modified self-bonding mounting clamps and corrective action if necessary. This AD results from an investigation that revealed the aluminum foil strip on the nylon base of the ground clamps can fracture or separate from the base. We are issuing this AD to ensure that the fuel pipes are properly bonded to the airplane structure. Improper bonding could prevent electrical energy from a lightning strike from dissipating to the airplane structure, which could result in a fuel tank explosion.

DATES:

This AD becomes effective November 8, 2006.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of November 8, 2006.

ADDRESSES:

You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Nassif Building, Room PL-401, Washington, DC.

Contact Boeing Commercial Airplanes, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024), for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT:

Serj Harutunian, Aerospace Engineer, Propulsion Branch, ANM-140L, FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712-4137; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Examining the Docket

You may examine the airworthiness directive (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 street address stated in the ADDRESSES section.

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to certain McDonnell Douglas Model 717-200 airplanes. That NPRM was published in the Federal Register on March 28, 2006 (71 FR 15351). That NPRM proposed to require replacing the lightning critical clamp bases of the fuel tank vent system with improved clamp bases; and checking the electrical bond of the modified self-bonding mounting clamps.

Actions Since NPRM Was Issued

Since we issued the NPRM, Boeing has released Service Bulletin 717-28-0004, Revision 3, dated June 21, 2006. In the NPRM, we referenced Revision 2 of the service bulletin, dated March 11, 2005, as the appropriate source of service information. The procedures in Revision 3 are essentially the same as those in Revision 2. Revision 3 also provides detailed instructions for checking the electrical bond of the modified self-bonding mounting clamps and accomplishing corrective actions if necessary. If the electrical conductivity of the surface is greater than 2.5 milliohms, the corrective actions include surface prepping and applying a chemical conversion coat to the surface of the structural bracket and vent pipe. (The NPRM proposed to repair the electrical bond of the mounting clamp according to a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, if any electrical bond fails the check. The NPRM specified that Chapter 28-00-00 of the Boeing 717 Aircraft Maintenance Manual and Chapter 20-50-01 of the Boeing 717 Standard Wiring Practices Manual (SWPM) are one approved method.)

We have revised paragraph (f) of this AD to reference Revision 3 as the appropriate source of service information for replacing the lightning critical clamp bases of the fuel tank vent system with improved clamp bases; and checking the electrical bond of the modified self-bonding mounting clamps. We have also revised paragraph (f) to allow operators to either repair any electrical bond in accordance with Revision 3 of the service bulletin, or according to a method approved by the Manager, Los Angeles ACO. In addition, we have added a new paragraph (g) to this AD, giving credit for actions done before the effective date of this AD in accordance with Revision 2. We have also revised the applicability of paragraph (c) of this AD to reference Revision 3. Revision 2 and Revision 3 both apply to Model 717-200 airplanes having fuselage numbers 5002 through 5121 inclusive; therefore, the applicability of this AD has not changed.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the comment received.

Support for the NPRM

Boeing and AirTran Airways support the NPRM.

Request for Clarification

AirTran Airways states that Boeing Service Bulletin 717-28-0004 refers to Chapter 20-50-01 of the Boeing DC, MD, and 717 SWPM, Class “L,” for instructions on accomplishing a check of the electrical bonds. AirTran Airways points out that Class “L” is not identified in Chapter 20-50-01 of the SWPM; instead, that chapter provides the maximum direct current (DC) resistance and path for lightning protection. Therefore, AirTran requests clarification of Class “L.”

As stated previously, since the NPRM was issued, Boeing has issued Revision 3 of the service bulletin and that revision is cited in this final rule. Revision 3 deletes the reference to Class “L.”

Conclusion

We have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

There are about 120 airplanes of the affected design in the worldwide fleet. This AD affects about 92 airplanes of U.S. registry. The required actions take about 16 work hours per airplane, at an average labor rate of $80 per work hour. Required parts cost about $239 per airplane. Based on these figures, the estimated cost of the AD for U.S. operators is $139,748, or $1,519 per airplane.

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 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.

We prepared a regulatory evaluation of the estimated costs to comply with this 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
• 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 Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

2006-20-12 McDonnell Douglas: Amendment 39-14782. Docket No. FAA-2006-24256; Directorate Identifier 2006-NM-010-AD.

Effective Date

(a) This AD becomes effective November 8, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to McDonnell Douglas Model 717-200 airplanes, certificated in any category; as identified in Boeing Service Bulletin 717-28-0004, Revision 3, dated June 21, 2006.

Unsafe Condition

(d) This AD results from an investigation that revealed the aluminum foil strip on the nylon base of the ground clamps can fracture or separate from the base. We are issuing this AD to ensure that the fuel pipes are properly bonded to the airplane structure. Improper bonding could prevent electrical energy from a lightning strike from dissipating to the airplane structure, which could result in a fuel tank explosion.

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.

Replace the Grounded Clamp Bases

(f) Within 78 months after the effective date of this AD, replace the lightning critical clamp bases of the fuel tank vent system with improved clamp bases, in accordance with Table 1 of Figure 1 of the Accomplishment Instructions of Boeing Service Bulletin 717-28-0004, Revision 3, dated June 21, 2006. Before further flight after the replacement, check the electrical bond of the modified self-bonding mounting clamps in accordance with the Accomplishment Instructions of the service bulletin. If any electrical bond fails the check, before further flight, repair the electrical bond of the mounting clamp in accordance with the service bulletin; or according to a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA. Chapter 28-00-00 of the Boeing 717 Aircraft Maintenance Manual and Chapter 20-50-01 of the Boeing DC, MD, and 717 Standard Wiring Practices Manual are one approved method.

Credit for Previous Service Bulletin

(g) Actions done before the effective date of this AD in accordance with Boeing Service Bulletin 717-28-0004, Revision 2, dated March 11, 2005, are acceptable for compliance with the requirements of paragraph (f) of this AD.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Los Angeles ACO, 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.

Material Incorporated by Reference

(i) You must use Boeing Service Bulletin 717-28-0004, Revision 3, dated June 21, 2006, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Boeing Commercial Airplanes, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024), for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., Room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov;​; or at the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call [phone], or go to http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html.

Issued in Renton, Washington, on September 25, 2006.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.