Airworthiness Directive · Amendment 39-13779 · Boeing Model 737-600, 737-700, 737-700C, 737-800, and 737-900 Series Airplanes
Boeing Model 737-600, 737-700, 737-700C, 737-800, and 737-900 Series Airplanes
Model 737-600, 737-700, 737-700C, 737-800, and 737-900 series airplanes, as listed in Boeing Alert Service Bulletin 737-26A1118, Revision 1, dated April 8, 2004; certificated in any category.
This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-600, 737-700, 737-700C, 737-800, and 737-900 series airplanes, that requires measuring the electrical resistance of the support bracket for the fire extinguisher bottle located in the left main landing gear wheel well to ensure that it does not exceed the maximum allowed resistance; and corrective actions, if necessary. This action is necessary to prevent high electrical resistance in the squib firing circuit, which could result in insufficient electrical current to fire the fire extinguisher bottle squib and discharge the fire extinguishing agent, which could lead to an uncontrolled engine fire. This action is intended to address the identified unsafe condition.
To prevent high electrical resistance in the squib firing circuit, which could result in insufficient electrical current to fire the fire extinguisher bottle squib and discharge the fire extinguishing agent, which could lead to an uncontrolled engine fire, accomplish the following:
(a) Except as provided by paragraph (b) of this AD: Within 90 days after the effective date of this AD, measure the electrical resistance of the dual ground studs of the support brackets for the fire extinguisher bottle located in the left main landing gear wheel well (including the applicable corrective actions) by accomplishing all actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 737-26A1118, Revision 1, dated April 8, 2004. Do the actions per the service bulletin. Any applicable corrective action must be accomplished prior to further flight.
(b) If, when accomplishing the bond resistance measurement described in Figure 4 of Boeing Alert Service Bulletin 737-26A1118, Revision 1, dated April 8, 2004, the resistance is found to be greater than 1.0 milliohms (0.001 ohms): Before further flight, do the actions in paragraph (b)(1) or (b)(2) of this AD.
(1) Rework the terminal installation per Figure 4 of the service bulletin.
(2) Rework the terminal installation per a method approved by the Manager, Seattle Aircraft Certification Office, FAA.
(c) Actions accomplished before the effective date of this AD per Boeing Telex M-7200-02-01401, dated September 9, 2002; or Boeing Alert Service Bulletin 737-26A1118, dated October 17, 2002; are considered acceptable for compliance with the corresponding action specified in this AD.
(d) In accordance with 14 CFR 39.19, the Manager, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056, is authorized to approve alternative methods of compliance (AMOCs) for this AD.
(e) Unless otherwise specified in this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 737-26A1118, Revision 1, dated April 8, 2004. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or 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.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
