2010-18624. Airworthiness Directives; The Boeing Company Model 737-300, -400, -500, -600, -700, and -800 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

We are adopting a new airworthiness directive (AD) for certain Model 737-300, -400, -500, -600, -700, and -800 series airplanes. This AD requires 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. This AD results from reports of low-pressure flex-hoses of the crew oxygen system that burned through due to inadvertent electrical current from a short circuit in the audio select panel. We are issuing this AD to prevent inadvertent electrical current, which can cause the low-pressure flex-hoses of the crew oxygen system to melt or burn, causing oxygen system leakage and smoke or fire.

DATES:

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.

ADDRESSES:

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 [phone], extension 1; 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:

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 [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Discussion

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.

Comments

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

Support of NPRM

Boeing concurs with the contents of the NPRM.

Request for Clarification of Cup-Type Oxygen Mask Applicability

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.

Request To Extend Compliance Time

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.

Request for Clarification of Conductive Oxygen Hose Part Numbers

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.

Conclusion

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.

Explanation of Change to Costs of Compliance

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.

Costs of Compliance

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.

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:

2010-16-06 The Boeing Company: Amendment 39-16383. Docket No. FAA-2010-0046; Directorate Identifier 2009-NM-086-AD.

Effective Date

(a) This airworthiness directive (AD) is effective September 9, 2010.

Affected ADs

(b) None.

Applicability

(c) This AD applies to the airplanes identified in paragraphs (c)(1) and (c)(2) of this AD, certificated in any category.

(1) The Boeing Company Model 737-300, -400, and -500 series airplanes, as identified in Boeing Service Bulletin 737-35A1053, Revision 1, dated June 1, 2000.

(2) The Boeing Company Model 737-600, -700, and -800 series airplanes, as identified in Boeing Service Bulletin 737-35A1058, Revision 1, dated June 1, 2000.

Subject

(d) Air Transport Association (ATA) of America Code 35: Oxygen.

Unsafe Condition

(e) This AD results from reports of low-pressure flex-hoses of the crew oxygen system that burned through due to inadvertent electrical current from a short circuit in the audio select panel. The Federal Aviation Administration is issuing this AD to prevent inadvertent electrical current, which can cause the low-pressure flex-hoses of the crew oxygen system to melt or burn, resulting in oxygen system leakage and smoke or fire.

Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Inspection and Replacement

(g) Within 36 months after the effective date of this AD, do an inspection to determine whether any low-pressure flex-hose of the crew oxygen system installed under the oxygen mask stowage box in the flight deck has a part number identified in Table 1 or Table 2 of this AD, as applicable. A review of airplane maintenance records is acceptable in lieu of this inspection if the part number of the low-pressure flex-hoses of the crew oxygen system can be conclusively determined from that review.

(1) For any hose having a part number identified in Table 1 or Table 2 of this AD, as applicable, before further flight, replace the hose with a new or serviceable part, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-35A1053, Revision 1, dated June 1, 2000; or Boeing Service Bulletin 737-35A1058, Revision 1, dated June 1, 2000; as applicable.

(2) For any hose not having a part number identified in Table 1 or Table 2 of this AD no further action is required by this paragraph.

Table 1—Applicable Part Numbers for Model 737-300, -400, and -500 Series Airplanes

Boeing specification part No.	Equivalent Boeing supplier part Nos.
	Puritan bennett	Hydraflow
10-60174-31	173470-31	37001-31
10-60174-35	173470-35	37001-35
10-60174-46	Not Applicable	37001-46
60B50059-99	Not Applicable	38001-99

Table 2—Applicable Part Numbers for Model 737-600, -700, and -800 Series Airplanes

Boeing specification part No.	Equivalent Boeing supplier part Nos.
	Puritan bennett	Hydraflow
10-60174-31	173470-31	37001-31
10-60174-35	173470-35	37001-35
60B50059-124	Not Applicable	38001-124

Parts Installation

(h) As of the effective date of this AD, no person may install a crew oxygen hose with a part number identified in Table 1 or Table 2 of this AD, as applicable, on any airplane.

Actions Accomplished According to Previous Issue of Service Bulletins

(i) Actions accomplished before the effective date of this AD in accordance with Boeing Alert Service Bulletin 737-35A1053, dated September 2, 1999; or Boeing Alert Service Bulletin 737-35A1058, dated September 2, 1999; as applicable; are considered acceptable for compliance with the corresponding actions specified in this AD.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to Attn: 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 [phone]; fax [phone]. Or, e-mail information to [e-mail].

(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 principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

Material Incorporated by Reference

(k) You must use Boeing Service Bulletin 737-35A1053, Revision 1, dated June 1, 2000; or Boeing Service Bulletin 737-35A1058, Revision 1, dated June 1, 2000; as applicable; 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, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone [phone], extension 1; fax [phone]; e-mail [e-mail]; Internet https://www.myboeingfleet.com.

(3) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

(4) You may also review copies of the service information that is incorporated by reference 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 July 16, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.