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PROPOSED AD |
THE BOEING COMPANY:
Docket No. FAA-2019-0478; Product Identifier 2019-NM-040-AD.
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(a) COMMENTS DUE DATE The FAA must receive comments on this AD action by August 22, 2019. (b) AFFECTED ADS This AD replaces AD 2017-12-07, Amendment 39-18922 (82 FR 27416, June 15, 2017). (c) APPLICABILITY This AD applies to all The Boeing Company Model 737-800, -900, and -900ER series airplanes, certificated in any category. (d) SUBJECT Air Transport Association (ATA) of America Code 21, Air conditioning. (e) UNSAFE CONDITION This AD was prompted by reports of in-flight failure of the left temperature control valve and control cabin trim air modulating valve. The FAA is issuing this AD to address the possible occurrence of temperatures in excess of 100 degrees Fahrenheit in the flight deck or the passenger cabin during cruise, which could lead to the impairment of the flightcrew and prevent continued safe flight and landing. (f) COMPLIANCE Comply with this AD within the compliance times specified, unless already done. (g) RETAINED VALVE REPLACEMENT, WITH REVISED COMPLIANCE LANGUAGE This paragraph restates the requirements of paragraph (g) of AD 2017 -12-07 with revised compliance language. For airplanes identified in Boeing Alert Service Bulletin 737-21A1203, dated June 8, 2016: Within 60 months after July 20, 2017 (the effective date of AD 2017-12-07), replace the left temperature control valve and control cabin trim air modulating valve, as applicable, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-21A1203, dated June 8, 2016. (h) NEW VALVE IDENTIFICATION AND REPLACEMENT For airplanes not identified in paragraph (g) of this AD with an original certificate of airworthiness or an original export certificate of airworthiness dated on or before the effective date of this AD, do the actions specified in paragraphs (h)(1) and (h)(2) of this AD. (1) Within 60 months after the effective date of this AD, perform a general visual inspection of the left temperature control valve and control cabin trim air modulating valve to determine the valve part numbers. A review of airplane maintenance records is acceptable in lieu of this inspection if the part numbers of the valves can be conclusively determined from that review. (2) If the left temperature control valve or control cabin trim air modul- ating valve has part number 398908-4: Within 60 months after the effective date of this AD, replace the left temperature control valve or control cabin trim air modulating valve in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737 -21A1203, dated June 8, 2016. (i) PARTS INSTALLATION PROHIBITION As of the effective date of this AD, no person may install a valve having part number 398908-4, in either the left temperature control valve location or the control cabin trim air modulating valve location on any airplane. (j) ALTERNATIVE METHODS OF COMPLIANCE (AMOCS) (1) The Manager, Seattle ACO Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the certification office, send it to the attention of the person identified in paragraph (k)(1) of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov. (2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. (3) An AMOC that provides an acceptable level of safety may be used for any repair, modification, or alteration required by this AD if it is approved by The Boeing Company Organization Designation Authorization (ODA) that has been authorized by the Manager, Seattle ACO Branch, FAA, to make those findings. To be approved, the repair method, modification deviation, or alteration deviation must meet the certification basis of the airplane, and the approval must specifically refer to this AD. (4) For service information that contains steps that are labeled as Required for Compliance (RC), the provisions of paragraphs (j)(4)(i) and (j)(4)(ii) of this AD apply. (i) The steps labeled as RC, including substeps under an RC step and any figures identified in an RC step, must be done to comply with the AD. If a step or substep is labeled "RC Exempt," then the RC requirement is removed from that step or substep. An AMOC is required for any deviations to RC steps, including substeps and identified figures. (ii) Steps not labeled as RC may be deviated from using accepted methods in accordance with the operator's maintenance or inspection program without obtaining approval of an AMOC, provided the RC steps, including substeps and identified figures, can still be done as specified, and the airplane can be put back in an airworthy condition. (k) RELATED INFORMATION (1) For more information about this AD, contact Julie Moon, Aerospace Engineer, Cabin Safety and Environmental Systems Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-3571; email: julie.moon@faa.gov. (2) For service information identified in this AD, contact Boeing Commer- cial 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 referenced 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. Issued in Des Moines, Washington, on June 24, 2019. Dionne Palermo, Acting Director, System Oversight Division, Aircraft Certification Service. DATES: The FAA must receive comments on this proposed AD by August 22, 2019.
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DEPARTMENT OF TRANSPORTATION Estimated Costs for Required Actions
The agency estimates the following costs to do any necessary On-Condition Costs
Authority for This Rulemaking |