AD/B737/297 Amdt 3 - De-Icing Fluids and Main Wheel Well Electrical Connectors (Cth)

AIRWORTHINESS DIRECTIVE On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B737/297 Amdt 2 and issues the following AD under subregulation 39.001(1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Boeing 737 Series Aeroplanes AD/B737/297 Amdt 3 De-Icing Fluids and Main Wheel 1/2012 Well Electrical Connectors

Applicability: Model 737-600, -700, -700C, -800 and -900 series aeroplanes.

Despite the new AD/B737/297 Amdt 3, an exclusion or an alternate method of compliance that was in force before the coming into effect of AD/B737/297 Amdt 3 continues to be in force. Requirement: 1. Either a. Determine aeroplane exposure to runway de-icing fluids containing potassium formate or potassium acetate by reviewing airport data on the type of components in the de-icing fluid used at airports that support aeroplane operations, or b. Perform a detailed inspection of the line replaceable units (LRU) electrical connectors (including the contacts and backshells) in the wheel well of the main landing gear (MLG) for corrosion (the presence of moisture, corrosion pits, or white coloured material build-up), in accordance with Boeing Alert Service Bulletin (ASB) 737-24A1148 Revision 1 dated 10 July 2003. 2. If, as a result of the Requirement 1.a. determination: a. It can be positively determined that an aeroplane has not been exposed, repeat Requirement 1. b. It can be determined that an aeroplane has been exposed or it cannot be conclusively determined that an aeroplane has not been exposed, perform the Requirement 1.b. inspection. Note 1: For the purposes of this Directive, 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."