AD 2003-26-07

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-90-30 airplanes, that requires a one-time general visual inspection of the circuit breakers to determine if discrepant circuit breakers are installed, and corrective action if necessary. This action is necessary to prevent internal overheating and arcing of circuit breakers and airplane wiring due to long-term use and breakdown of internal components of the circuit breakers, which could result in smoke and fire in the flight compartment and main cabin. This action is intended to address the identified unsafe condition.

Final rule.

2003-26-07 McDonnell Douglas: Amendment 39-13404. Docket 2002-NM-103-AD. \n\n\tApplicability: Model MD-90-30 airplanes, as listed in Boeing Alert Service Bulletin MD90-24A081, Revision 01, dated March 7, 2003; certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent internal overheating and arcing of circuit breakers and airplane wiring due to long-term use and breakdown of internal components of the circuit breakers, which could result in smoke and fire in the flight compartment and main cabin, accomplish the following: \n\nInspection and Replacement \n\n\t(a) Within 18 months after the effective date of this AD: Perform a one-time general visual inspection of the circuit breakers to determine if discrepant circuit breakers are installed (includes circuit breakers manufactured by Wood Electric and Wood Electric Division of Brumfield Potter Corporations, and incorrect circuit breakers installed per Boeing Alert Service Bulletin MD90-24A081, dated February 14, 2002), per Boeing Alert Service Bulletin MD90-24A081, Revision 01, dated March 7, 2003. Instead of performing the one-time inspection, a review of the airplane maintenance records is acceptable if the part number of the discrepant circuit breakers can be positively determined by that review. \n\n\tNote 1: For the purposes of this AD, a general visual inspection is defined as: "A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximityto the area being checked." \n\n\t(1) If no discrepant circuit breaker is found: No further action is required by this paragraph. \n\n\t(2) If any discrepant circuit breaker is found: Before further flight, replace the circuit breaker with a new, approved circuit breaker, per the service bulletin. \n\nPart Installation \n\n\t(b) As of the effective date of this AD, no person shall install a circuit breaker manufactured by Wood Electric Corporation or Wood Electric Division of Potter Brumfield Corporation on any airplane. \n\nAlternative Methods of Compliance \n\n\t(c) In accordance with 14 CFR 39.19, the Manager, Los Angeles Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance for this AD. \n\nIncorporation by Reference \n\n\t(d) Unless otherwise provided in this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin MD90-24A081, Revision 01, dated March 7, 2003. This incorporation by reference was approved by the Director ofthe Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Aircraft Group, Long Beach Division, 3855 Lakewood Boulevard, Long Beach, California 90846, Attention: Data and Service Management, Dept. C1-L5A (D800-0024). Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\nEffective Date \n\n\t(e) This amendment becomes effective on February 4, 2004.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-90-30 airplanes was published in the Federal Register on June 11, 2003 (68 FR 34849). That action proposed to require a one-time general visual inspection of the circuit breakers to determine if discrepant circuit breakers are installed, and corrective action if necessary. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the single comment received. \n\nRequest for Clarification of Applicability \n\n\tThe commenter, an operator, requests clarification of the applicability listed in the proposed AD. The commenter states that it has nine airplanes that are included in the applicability listed in the proposed AD. Because no Wood Electric circuit breakers were installed on its newlydelivered airplanes or installed on any airplane during maintenance, those airplanes fall into "Group 1, Condition 1," as listed in Boeing Alert Service Bulletin MD90-24A081, Revision 01, dated March 7, 2003 (which was referenced as the appropriate source of service information for accomplishment of the inspection in the proposed AD). For those airplanes, the alert service bulletin states that no action is required. However, the proposed AD would require those airplanes to be inspected to determine if any Wood Electric circuit breaker is installed even though the commenter knows the circuit breakers are not installed. \n\n\tThe FAA agrees that clarification is necessary. Paragraph (a) of the AD does require that all airplanes listed in the applicability statement of the AD be inspected to verify installation of the discrepant circuit breaker. However, the airplane manufacturer has determined that no Model MD-90-30 airplanes were delivered with the subject discrepant circuit breakers installed. Therefore, instead of accomplishing the inspection provided in paragraph (a) of the AD, we will allow operators to review the airplane maintenance records to determine if any discrepant circuit breaker was installed on the airplane after delivery--if the part number of the circuit breakers can be positively determined from that review. We have revised paragraph (a) of this final rule accordingly. \n\nConclusion \n\n\tAfter careful review of the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nChange to Labor Rate \n\n\tWe have reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary toincrease the labor rate used in these calculations from $60 per work hour to $65 per work hour. The cost impact information, below, reflects this increase in the specified hourly labor rate. \n\nCost Impact \n\n\tThere are approximately 126 airplanes of the affected design in the worldwide fleet. The FAA estimates that 21 airplanes of U.S. registry will be affected by this AD, that it will take approximately 20 work hours per airplane to accomplish the required inspection of the circuit breakers (over 700 installed on each airplane), and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $27,300, or $1,300 per airplane. \n\n\tThe cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \n\nRegulatory Impact \n\n\tThe regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. \n\n\tFor the reasons discussed above, I certify that this action (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 ornegative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39-AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: