Document ID: chunk:federal_register_of_legislation:F2005L02832:body:0:p1
Version: federal_register_of_legislation:F2005L02832
Segment Type: other
Provision Reference: 
Character Range: 0–3061

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/LEARJET/36 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.

Gates Learjet 24 & 25 Series Aeroplanes
AD/LEARJET/36 Amdt 1  Tip Tank Flapper Valves  11/2005

Applicability:  Model 24 aeroplanes S/N 24-100 through 24-357 inclusive.

                Model 25 aeroplanes  S/N 25-002 through 25-373 inclusive.
Requirement:       1. Perform an inspection to detect deterioration (such as cracks, cuts, breaks, splits, or warpage) of both flappers of the tip tank in each wing, in accordance with either Learjet Service Bulletin SB 23/24/25-28-2, dated 6 October 1995.

                     (a) If no deterioration of the flapper valve is detected, inspect the flapper valve to ensure proper positioning, inspect the condition of the screws that retain the flapper valve to the plate assembly to ensure that the flapper valve is secure, inspect to ensure that the flapper valve completely covers the opening of the tube and is seated against the tube, and inspect the flapper valve to verify that it moves freely; and accomplish the follow-on corrective actions, if any discrepancy is found in accordance with Learjet Service Bulletin SB 23/24/25-28-2.

                     (b) If any flapper valve is found to be deteriorated, replace it with a new flapper valve in accordance with Learjet Service Bulletin SB 23/24/25-28-2.

                   2. Replace both flappers of the tip tank in each wing with new flappers in accordance with Learjet Service Bulletin SB 23/24/25-28-2.

                   3. For aeroplanes on which the age and time-in-service of the flapper valve cannot be determined: replace both flappers of the tip tank in each wing in accordance with Learjet Service Bulletin SB 23/24/25-28-2.

                   4. Accomplish the requirements of Requirement 1 of this Directive.

                   5. Inspect the flappers and flapper assemblies of the tip tank in each wing to determine their part numbers (P/N).  The raised letter and numbers "S-461" on the convex side of the flappers can identify these parts.  Instead of inspecting the flappers and flapper assemblies, a review of aeroplane maintenance records is acceptable if the P/N of the flappers and flapper assemblies can be conclusively determined from that review.

                     (a) If four flappers having P/N 2323006-802 and four flapper assemblies having P/N 2323006-801 are found