SB A45-29-15

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THIS SERVICE BULLETIN IS AVAILABLE AT:

www.cic.bombardier.com

Basic Issue: Dec 26/06

Refer to applicable government agency regulations and requirements and make sure that the work described 

in this Service Bulletin is performed in compliance with manufacturer’s recommendations and/or acceptable industry standards. 

This document is proprietary to Bombardier Inc. and/or its affiliates and may not be reproduced or copied in any form or by any means without the prior written consent of Bombardier Inc. and/or its affiliates. 

© 2006, Bombardier Inc. All rights reserved. Challenger*, Global Express*, Learjet*, are Trademarks of Bombardier Inc.

LEARJET 45

ALERT

SB A45-29-15

SERVICE BULLETIN

If you cannot do all steps in this service bulletin because of an STC change to the aircraft, speak to the STC

holder or the regional Federal Aviation Administration (FAA) office for information and disposition.

HYDRAULIC POWER - INSPECTION/REPLACEMENT OF THE LEFT HYDRAULIC PUMP CASE

DRAIN TUBE

1. Planning Information

A. Effectivity

(1) Learjet 45-005 thru 45-313.

B. Reason

(1) The left engine hydraulic pump case drain tube has been found to be chafing on the lower forward

cowl latch structure on the inboard side of the engine. This condition may cause premature failure

of the drain tube, and possible leakage of hydraulic fluid within the engine cowling.

C. Description

(1) This service bulletin provides instructions to inspect the left engine hydraulic pump case drain tube

for chafing or other damage. Instructions are also provided to either reposition or replace the tube,

based on inspection results.

D. Compliance

(1) Recommended - Bombardier Learjet Inc. recommends that you do this service bulletin in less than

50 flight hours from the initial distribution date of this service bulletin.

CONTACT INFORMATION DISTRIBUTION 

DATE

Business Aircraft

Learjet Inc.

MS 53

P.O. Box 7707

Wichita, Kansas 67277-7707

(316) 946-2421

December 26, 2006
SB A45-29-15

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LEARJET 45

SERVICE BULLETIN

THIS SERVICE BULLETIN IS AVAILABLE AT:

www.cic.bombardier.com

Basic Issue: Dec 26/06

E. Approval

(1) The Federal Aviation Administration (FAA) has approved the technical content in this publication

that has an effect on the airplane type design.

(2) The European Aviation Safety Agency (EASA) has accepted the technical content in this publication that has an effect on the airplane type design.

F. Labor Hours - Estimated Accomplishment Time

NOTE: These labor hours are an estimate and are for planning purposes only. Facility and personnel capabilities may cause the labor hours to change.

G. Expense Coverage

(1) Labor Coverage - Labor coverage applies to all aircraft included in this service bulletin.

NOTE: For labor coverage to apply, you must do this service bulletin at a Bombardier Business Aviation Service Facility or at a Bombardier Learjet Authorized Service Facility.

You must do this service bulletin within 12 months from the release date of this service

bulletin basic issue, December 26, 2006.

(2) Material Coverage - Material coverage applies to all aircraft included in this service bulletin.

NOTE: For material coverage to apply, you must place an order for the parts in this service

bulletin from Bombardier within 12 months from the basic issue distribution date of this

service bulletin, December 26, 2006.

(3) Smart Parts 

(a) During or after the above free period, Smart Parts Plus does not pay for any parts to do this

service bulletin.

AIRCRAFT 

THAT REQUIRE 

MODIFICATION

AIRCRAFT 

THAT DO NOT 

REQUIRE

MODIFICATION

TASK

0.5 0.5 Labor hours to gain access.

1.0 0.5 Labor hours to do the aircraft inspection/modification.

2.0 N/A Labor hours to do a functional test/operational check.

0.5 0.5 Labor hours to return the aircraft to airworthy status.

4.0 1.5 Total Labor Hours
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LEARJET 45

SERVICE BULLETIN

THIS SERVICE BULLETIN IS AVAILABLE AT:

www.cic.bombardier.com

Basic Issue: Dec 26/06

H. Material Required to do this Service Bulletin

(1) There are no kits associated with this service bulletin.

(2) Other parts that may be necessary to do this service bulletin.

NOTE: The above price can change.

To place an order for these material/parts, please call Bombardier Aerospace Parts

Logistics Business Aircraft Customer Service at 1-888-222-1428 in North America or

1-316-946-2377 outside North America for information.

I. Tooling

(1) None.

J. Weight and Balance

(1) Negligible.

K. References

(1) Learjet Maintenance Manual, Chapters 20, 24, and 71.

L. Other Publications Affected

(1) Learjet Illustrated Parts Catalog, Chapter 29.

2. Accomplishment Instructions

A. Gain Access

(1) Disconnect the external electrical power and the main and emergency batteries from aircraft.

(Refer to Learjet Maintenance Manual, Chapter 24.)

(2) Remove the left engine lower cowling (450CL). (Refer to Learjet Maintenance Manual, Chapter

71.)

B. Inspection/Modification of Aircraft

(1) Inspect the left engine hydraulic pump case drain tube as follows;

(a) Examine the tube for chafing and/or other damage in the critical inspection area shown. (See

Figure 1, View B-B.) 

NOTE: Damage must not be more than 20% (.004 in [0.10 mm]) of the wall thickness of

the tube.

PART NUMBER NAME QTY PRICE

4529101090-005 Tube Assembly 1 $285.00

4529101090-001 Tube Assembly

(Alternate for 

4529101090-005)

1 $285.00
SB A45-29-15

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LEARJET 45

SERVICE BULLETIN

THIS SERVICE BULLETIN IS AVAILABLE AT:

www.cic.bombardier.com

Basic Issue: Dec 26/06

(b) On aircraft where the tube is damaged more than the acceptable limits, replace the tube. (See

Figure 1, View C.)

NOTE: It may be necessary to reposition the flexible hose assembly to facilitate connection of the new hydraulic pump case drain tube assembly. (See Figure 1, View BB.)

(c) On aircraft where damage to the tube is within acceptable limits, proceed to paragraph 2.B.(2).

(d) On aircraft where there is no damage to the tube, no further action is required. Proceed to

paragraph 2.D. to return the aircraft to airworthy status.

(2) On aircraft that require the tube to be repositioned due to chafing or other damage, position the

tube as follows;

(a) Loosen the clamp that secures the tube so the tube can be moved within the clamp. (See Figure 1, View B-B.) 

(b) Loosen the B-nut on the end of the flexible hose that is attached to the union installed in the

top of the hydraulic pump case.

NOTE: Loosen the B-nut only enough to move the hose within an arc of approximately 30

degrees. 

(c) Position the flexible hose as necessary to provide clearance for the tube. (See Figure 1, View

B-B.)

(d) Tighten the B-nut of the flexible hose in the position that provides the best clearance of the

tube. 

(e) Torque the B-nut as necessary. (Refer to Learjet Maintenance Manual, Chapter 20.)

NOTE: Make sure the position of the hose does not change when you torque the B-nut.

C. Functional Test/Operational Check

(1) On aircraft that were required to reposition or replace the tube, do the checks that follow;

(a) Connect the main and emergency batteries to the aircraft. (Refer to Learjet Maintenance Manual, Chapter 24.)

(b) Connect external electrical power. (Refer to Learjet Maintenance Manual, Chapter 24.)

(c) Start the left engine.

(d) Make sure the main hydraulic system pressure shows 3000 PSI ± 100 PSI [20684 ± 689 kPa]

on the EICAS system.

(e) Examine for leaks around the tube and flexible hose fittings.

(f) Shut down the left engine.

D. Return Aircraft to Airworthy Status

(1) Install the left engine lower cowling (450CL). (Refer to Learjet Maintenance Manual, Chapter 71.)

(2) On aircraft that were not required to reposition or replace the tube, connect the main and emergency batteries to the aircraft. (Refer to Learjet Maintenance Manual, Chapter 24.)
SB A45-29-15

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LEARJET 45

SERVICE BULLETIN

THIS SERVICE BULLETIN IS AVAILABLE AT:

www.cic.bombardier.com

Basic Issue: Dec 26/06

E. Compliance Response Form

(1) Complete the compliance response form.

(2) Send the compliance response form to Learjet Inc. as soon as possible.

F. Aircraft Maintenance Records

(1) Complete the Aircraft Maintenance Records.

NOTE: To complete the aircraft maintenance records, refer to FAR/CFR 43.9.

3. Material Information

A. Parts Required

(1) There are no kits for this service bulletin. Refer to paragraph 1.H. for more material/parts necessary to do this service bulletin. 

B. Parts Removed List

PART 

NUMBER QTY NOMENCLATURE DISPOSITION EFFECTIVITY REPLACED BY

4529101090-001 1 Tube Assembly Destroy All 4529101090-005

or 

4529101090-001

(Alternate for 

4529101090-005)
SB A45-29-15

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LEARJET 45

SERVICE BULLETIN

THIS SERVICE BULLETIN IS AVAILABLE AT:

www.cic.bombardier.com

Basic Issue: Dec 26/06

Left Hydraulic Pump Case Drain Tube Installation

Figure 1 (Sheet 1 of 3)
SB A45-29-15

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LEARJET 45

SERVICE BULLETIN

THIS SERVICE BULLETIN IS AVAILABLE AT:

www.cic.bombardier.com

Basic Issue: Dec 26/06

Left Hydraulic Pump Case Drain Tube Installation

Figure 1 (Sheet 2 of 3)
SB A45-29-15

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LEARJET 45

SERVICE BULLETIN

THIS SERVICE BULLETIN IS AVAILABLE AT:

www.cic.bombardier.com

Basic Issue: Dec 26/06

Left Hydraulic Pump Case Drain Tube Installation

Figure 1 (Sheet 3 of 3)
SERVICE BULLETIN COMPLIANCE RESPONSE 

It is necessary that Bombardier Learjet record aircraft having complied with this 

Service Bulletin. Please fill in the Service Bulletin and aircraft information below, 

sign and date the form in the space provided, fold on dotted lines, seal with tape, 

and mail completed form to Bombardier Learjet Maintenance Engineering. If 

mailed within the United States, this form may be mailed to Bombardier Learjet 

Maintenance Engineering using business reply mail (see reverse). This form may 

be faxed or e-mailed if preferred. (See mailing information provided.)

WARRANTY - Completion of this response form is required in order to process 

the warranty claim. Therefore, if a warranty allowance is provided in the Service 

Bulletin, return a copy of this form with the warranty claim. 

SMART PARTS - Completion of this response form is required in order to 

remain, enroll, or re-enroll in the Smart Parts Program.

b

Mailing Information: 

Bombardier Learjet 

Maintenance Engineering 

(MS #78) (FAX 316 946-2305) 

fracas_usa@aero.bombardier.com 

Customer Support 

Learjet, Inc.

Service Bulletin Information Aircraft Information 

Service Bulletin No. A45-29-15 Model 

Rev No. Basic Date December 26, 2006 Serial No. 

Service Facility Information Flight Hours 

Facility Incorporating Bulletin Landings 

Compliance Information 

The above referenced Service Bulletin was complied with on the referenced serial number aircraft at the listed aircraft flight 

hours/landings: 

Actual hours to accomplish Service Bulletin: Access _______ SB _______ Test(s) _______ Restore _______ 

Signature Title Date 

Comments

SERVICE BULLETIN EVALUATION SHEET

YOUR COMMENTS WILL HELP US IMPROVE OUR 

SERVICE BULLETINS 

b

SERVICE BULLETIN A45-29-15 REVISION: Basic DATED: December 26, 2006 

TITLE: Inspection/Replacement of the Left Hydraulic Pump Case Drain Tube

LEARJET CONTACT INFORMATION TELEPHONE: (316) 946-2421 FACSIMILE: (316) 946-2002 

HOW EASY IS THE BULLETIN TO UNDERSTAND? POOR FAIR GOOD VERY 

GOOD

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