AD 2010-16-06

This AD is effective September 9, 2010.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the AD as of September 9, 2010.

For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com.

Susan L. Monroe, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6457; fax (425) 917-6590.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to certain Model 737-300, -400, -500, -600, -700, and -800 series airplanes. That NPRM was published in the Federal Register on January 22, 2010 (75 FR 3662). That NPRM proposed to require inspecting to verify the part number of the low-pressure flex-hoses of the crew oxygen system installed under the oxygen mask stowage boxes located within the flight deck, and replacing the flex-hose with a new non-conductive low-pressure flex-hose if necessary.

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

Boeing concurs with the contents of the NPRM.

All Nippon Airways requests that the FAA clarify the NPRM by including a note stating that the cup-type oxygen mask at the observer seat position is not included in the applicability statement of the NPRM, as stated in a note in the Accomplishment Instructions of Boeing Service Bulletin 737-35A1053, Revision 1, dated June 1, 2000.

We agree that clarification is necessary. Boeing Service Bulletin 737-35A1053, Revision 1, dated June 1, 2000, provides information that describes the applicable parts and equipment. ADs do not identify parts and equipment that are not applicable; therefore, the cup-type oxygen mask is not included in the applicability statement. No change has been made to the AD in this regard.

The Air Transport Association on behalf of its member American Airlines, requests that the 36-month compliance time be extended to 72 months to allow accomplishment during heavy maintenance. American Airlines states that this extended compliance time would be consistent with the apparent urgency being placed on this inspection by the FAA, which has waited over ten years since the original release of the service bulletin to issue the NPRM. American Airlines also states that the compliance urgency should also take into account that the proposed AD results from reports of hoses that burned through on a Model 757 airplane due to electrical current from a short circuit in the audio selector panel with no mention of reports of burned-through hoses on properly maintained Model 737 airplanes.

We do not agree. American Airlines provides no technical justification for extending the compliance time. In developing an appropriate compliance time, we considered the safety implications, parts availability, and normal maintenance schedules for timely accomplishment of the required actions. Further, we arrived at the compliance time with manufacturer concurrence. In consideration of all of these factors, we determined that the compliance time, as proposed, represents an appropriate interval in which the inspections can be done in a timely manner within the fleet, while still maintaining an adequate level of safety. If additional data are presented that would justify a longer compliance time, we may consider further rulemaking on this issue. No change has been made to the AD in this regard.

The Air Transport Association on behalf of its member American Airlines, requests clarification regarding the conductive oxygen hose part numbers in Table 1 of the NPRM and the applicable airplane models. American Airlines states that the NPRM requires inspections for five conductive hose part numbers regardless of model applicability, and does not differentiate between part numbers that are applicable to Model 737-300, -400, and -500 series airplanes, and those applicable to Models 737-600, -700, and -800 series airplanes. American Airlines states that if an operator who flies only Model 737-800 series airplanes has accomplished Boeing Service Bulletin 737-35A1058, Revision 1, dated June 1, 2000, for Model 737-800 airplanes prior to the effective date of the NPRM, the operator would now be required to perform another inspection to look for the part numbers in Boeing Service Bulletin 737-35A1053, Revision 1, dated June 1, 2000, which does not apply to Model 737-800 airplanes. American Airlines asserts that this places undue burden and expense on the operator.

We agree that clarification is needed regarding the conductive hose part numbers. We have changed Table 1 of this final rule to identify part numbers for only Model 737-300, -400, and -500 series airplanes. Table 2 has been added to this final rule to identify part numbers for Model 737-600, -700, and -800 series airplanes.

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We also determined that these changes will not increase the economic burden on any operator or increase the scope of the AD.

Since issuance of the NPRM, we have increased the labor rate used in the Costs of Compliance from $80 per work-hour to $85 per work-hour. The Costs of Compliance information, below, reflects this increase in the specified hourly labor rate.

We estimate that this AD will affect 851 airplanes of U.S. registry. We also estimate that it will take 1 work-hour per product to comply with this AD. The average labor rate is $85 per work-hour. Based on these figures, we estimate the cost of this AD to the U.S. operators to be $72,335, or $85 per product.

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.

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.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new AD: