Airworthiness Directive · Amendment 39-14264 · Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes
Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes
(c) This AD applies to all Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes; certificated in any category.
(d) This AD was prompted by additional reports indicating that significant corrosion of the electrical connectors in the wheel well of the MLG has also been found on airplanes that land on runways treated with deicing fluids containing potassium acetate. We are issuing this AD to prevent corrosion and subsequent moisture ingress into the electrical connectors, which could result in an electrical short and consequent incorrect functioning of critical airplane systems essential to safe flight and landing of the airplane, including fire warning systems.
The FAA is superseding an existing airworthiness directive (AD), which applies to all Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. That AD currently requires either determining exposure to runway deicing fluids containing potassium formate, or performing repetitive inspections of certain electrical connectors in the wheel well of the main landing gear (MLG) for corrosion, and follow-on actions. This new AD adds a new inspection requirement and related corrective actions. This AD is prompted by additional reports indicating that significant corrosion of the electrical connectors in the wheel well of the MLG has also been found on airplanes that land on runways treated with deicing fluids containing potassium acetate. We are issuing this AD to prevent corrosion and subsequent moisture ingress into the electrical connectors, which could result in an electrical short and consequent incorrect functioning of critical airplane systems essential to safe flight and landing of the airplane, including fire warning systems.
(f) Within 12 months after the effective date of this AD: Perform the actions required by either paragraph (f)(1) or (f)(2) of this AD.
(1) Determine airplane exposure to runway deicing fluids containing potassium formate or potassium acetate by reviewing airport data on the type of components in the deicing fluid used at airports that support airplane operations.
(i) If the airplane has not been exposed, repeat the requirements specified in paragraph (f)(1) of this AD thereafter at intervals not to exceed 12 months.
(ii) If the airplane has been exposed, within 90 days after that determination is made, do the inspection required by paragraph (f)(2) of this AD; and repeat the inspection thereafter at intervals not to exceed 12 months.
(2) Do a detailed inspection of the electrical connectors, including the contacts and backshells, of the line replaceable unit (LRU) in the wheel well of the MLG for corrosion by doing all the actions in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-24A1148, Revision 1, dated July 10, 2003. Do any significant/corrective actions before further flight in accordance with the service bulletin.
Note 1: For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
(g) Inspections accomplished before the effective date of this AD in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-24A1148, dated December 6, 2001, are acceptable for compliance with the inspections required by paragraph (f)(2) of this AD.
(h)(1) The Manager, Seattle Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.
(2) AMOCs approved previously in accordance with AD 2002-16-03, amendment 39-12842, are not approved as AMOCs with this AD.
(i) You must use Boeing Alert Service Bulletin 737-24A1148, Revision 1, dated July 10, 2003, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approves the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. To get copies of the service information, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. To view the AD docket, go to the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW, room PL-401, Nassif Building, Washington, DC. To review copies of the service information, go to the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
