AD 2018-09-12

This AD is effective May 30, 2018.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of May 30, 2018.

We must receive comments on this AD by June 29, 2018.

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.

• Fax: 202-493-2251.

• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this final rule, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone 562-797-1717; internet https://www.myboeingfleet.com. You may view this service information at the FAA, Transport Standards Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. It is also available on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2018-0362.

Susan L. Monroe, Aerospace Engineer, Cabin Safety and Environmental Systems Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-3570; email: susan.l.monroe@faa.gov.

This AD was prompted by reports of low-pressure oxygen flex-hoses in the continuously pressurized flightcrew oxygen system that burned through due to inadvertent electrical current from a short circuit. Conductive oxygen hoses in the flight deck were addressed previously in AD 2010-16-05, Amendment 39-16382 (75 FR 47208, August 5, 2010) (“AD 2010-16-05”).

The gaseous passenger oxygen system equipped with therapeutic oxygen is not continuously pressurized and must be activated by the flightcrew. Exposure to electrical faults, such as unintended short circuits, can result in localized electrical heating of the low-pressure oxygen flex-hoses. This condition, if not corrected, could result in electrical current passing through the low-pressure oxygen flex-hoses, which can cause flex-hoses to melt or burn, and a consequent oxygen-fed fire in the passenger cabin.

We issued AD 2010-16-05 for certain The Boeing Company Model 747 airplanes. AD 2010-16-05 was prompted by reports of low-pressure flex-hoses of the flightcrew oxygen system that burned through due to inadvertent electrical current from a short circuit in the audio select panel. AD 2010-16-05 requires inspecting to verify the part number of the low-pressure flex-hoses of the flightcrew oxygen system installed under the oxygen mask stowage boxes in the flight deck, and replacing the flex-hose with a new non-conductive low-pressure flex-hose if necessary. We issued AD 2010-16-05 to prevent inadvertent electrical current, which can cause the low-pressure flex-hoses of the flightcrew oxygen system to melt or burn, causing oxygen system leakage and smoke or fire.

We reviewed Boeing Special Attention Service Bulletin 747-35-2134, dated November 22, 2017. The service information describes procedures for replacing certain low-pressure oxygen flex-hose assemblies with non-conductive flex-hose assemblies at multiple locations and a general visual inspection to ensure the oxygen system components have minimum clearance from adjacent structure and systems. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

We are issuing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design.

This AD requires accomplishment of the actions identified as “RC” (required for compliance) in the Accomplishment Instructions of Boeing Special Attention Service Bulletin 747-35-2134, dated November 22, 2017, described previously, except as discussed under “Differences Between this AD and the Service Information,” and except for any differences identified as exceptions in the regulatory text of this AD.

For information on the procedures and compliance times, see this service information at http://www.regulations.gov by searching for and locating Docket No. FAA-2018-0362.

Where the Condition column of Table 3 in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 747-35-2134, dated November 22, 2017, specifies “all airplanes,” for this AD, the Condition column of Table 3 is “airplanes on which one or more hose assemblies were replaced or disconnected.” As specified in step 3.B.12 of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 747-35-2134, dated November 22, 2017, the oxygen system low-pressure leak test and applicable corrective actions are only accomplished if one or more hose assemblies were replaced or disconnected.

There are currently no domestic operators of this product. Therefore, we find that notice and opportunity for prior public comment are unnecessary and that good cause exists for making this amendment effective in less than 30 days.

This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment. However, we invite you to send any written data, views, or arguments about this final rule. Send your comments to an address listed under the ADDRESSES section. Include the docket number FAA-2018-0362 and Product Identifier 2018-NM-020-AD at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this final rule. We will consider all comments received by the closing date and may amend this final rule because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this final rule.

Currently, there are no affected U.S.-registered airplanes. If an affected airplane is imported and placed on the U.S. Register in the future, we provide the following cost estimates to comply with this AD:

We have received no definitive data that would enable us to provide cost estimates for the on-condition actions specified in this AD.

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 is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to transport category airplanes to the Director of the System Oversight Division.

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),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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.

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 airworthiness directive (AD):