AD/LJ45/13 Left Hand Engine Hydraulic Tubes (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (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.

Learjet 45 Series Aeroplanes

AD/LJ45/13 Left Hand Engine Hydraulic Tubes 8/2009

Applicability:

Learjet Model 45 aeroplanes, serial numbers (S/N) 45-002 through 45-4000 inclusive.

Requirement:

1.    For aeroplanes having serial numbers identified in Table 1 of this AD:

Do a detailed inspection for chafing and other damage of the case drain tube from the hydraulic pump case installed on the left-hand engine, in accordance with the applicable service bulletin identified in Table 1 of this AD.  If any damage is found, reposition or replace the tube, as applicable, in accordance with the Accomplishment Instructions of the service bulletin identified in Table 1 of this AD, as applicable.

Table 1 - Service Bulletins for Inspections

For -	Use -
Serial numbers 45-005 through 45-313 inclusive (commonly referred to as “M45” aeroplanes)	Bombardier Alert Service Bulletin A45-29-15, dated December 26, 2006.
Serial numbers 45-2001 through 45-2063 inclusive (commonly referred to as “M40” aeroplanes)	Bombardier Alert Service Bulletin A40-29-03, dated December 26, 2006.

For the purposes of this AD, a detailed inspection is: "An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity.  Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate.  Inspection aids such as mirror, magnifying lenses, etc., may be necessary.  Surface cleaning and elaborate procedures may be required.''

2.    Do a detailed inspection for discrepancies of the left engine's nacelle tubing, in accordance with the applicable temporary revision (TR) identified in Table 2 of this AD.  Discrepancies include damaged tubing, and inadequate clearance between any unsupported section of the tube or other tubing and surrounding components.  If any discrepancy is found, adjust the tubing and clamping or replace the tubing, as applicable, in accordance with the applicable TR identified in Table 2 of this AD.

Table 2 - TRs for Inspections

For -	Use -
Serial numbers 45-2001 through 45-4000 inclusive (commonly referred to as “M40” aeroplanes)	Learjet 40 TR 71-1, dated April 28, 2009, to the Learjet 40 Maintenance Manual MM-105.
Serial numbers 45-002 through 45-2000 inclusive (commonly referred to as “M45” aeroplanes)	Learjet 45 TR 71-1, dated April 28, 2009, to the Learjet 45 Maintenance Manual MM-104.

3.    Do a detailed inspection for evidence of engine oil, hydraulic fluid, or fuel leakage within the left engine accessory compartment, in accordance with the applicable maintenance manual section identified in Table 3 of this AD.  If there is evidence of leakage - remove each plumbing clamp within the inspection areas specified in Requirements 1 and 2 of this AD, and clean and remove all evidence of fluid leakage.

Table 3 - Maintenance Manual Sections for Inspections

For -	Use -
Serial numbers 45-002 through 45-2000 inclusive (commonly referred to as “M45” aeroplanes)	Section 71-00-00, “Powerplant - Maintenance Practices,” Revision 3, dated April 10, 1998, and Section 71-00-01, “Engine - Maintenance Practices,” Revision 44, dated April 28, 2008, to the Learjet 45 Maintenance Manual MM-104
Serial numbers 45-2001 through 45-4000 inclusive (commonly referred to as “M40” aeroplanes)	Section 71-00-01, “Engine - Maintenance Practices,” Revision 8, dated December 25, 2006, to the Learjet 40 Maintenance Manual MM-105

4.    If evidence of fluid leakage was found during any inspection detailed in Requirement 3 of this AD, or, if inadequate clearance was found during any action detailed in Requirement 1 or 2 of this AD - replace each clamp associated with the fluid leakage or inadequate clearance with a new clamp, in accordance with the applicable maintenance manual identified in Table 3 of this AD.

5.    Do not re- install, on any aeroplane, any plumbing clamp that has been removed in accordance with the requirements of this AD.

Later revisions of the above SB(s) , approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2009-11-13, are considered acceptable for compliance with the equivalent Requirements of this AD.

Note:  FAA AD 2009-11-13 Amdt 39-15923 dated 20 May 2009 refers.

Compliance:

For Requirements 1 and 2 - Initial inspection within 50 flight hours (FH) after the effective date of this AD, unless previously accomplished.

Thereafter repeat the inspection at intervals not to exceed 150 FH.

For Requirement 3 - Concurrently with Requirement 2.

For Requirement 4 - Before further flight.

For Requirement 5 - As of the effective date of this AD.

This Airworthiness Directive becomes effective on 30 July 2009.

Background:

This AD results from reports of chafed hydraulic tubes in the left-hand engine.  The issuing of this AD is intended to detect and correct chafed hydraulic tubes in the left - hand engine and consequent hydraulic tube failure and uncontrolled loss of flammable fluid within the engine cowling, which could result in a fire in the engine nacelle and loss of control of the aeroplane.

James Coyne
Delegate of the Civil Aviation Safety Authority

15 June 2009