# TRANSMITTAL SHEET

November 13, 2015 Transmittal Page 1 This sheet transmits Revision A, dated November 13, 2015, to Gulfstream G650 Alert Customer Bulletin (ACB) 4, dated November 6, 2015, titled Landing Gear (ATA 32), Inspection – Brake Inlet Self-Sealing Couplings Torque.
Reason for Revision: After regulatory review of ACB No. 4, the Federal Aviation Administration (FAA) has requested a revised coupling re-torque procedure to loosen the coupling and record the break-away torque prior to torquing the coupling. Procedures are clarified to more accurately explain the torquing procedure and conform to recent changes to the Aircraft Maintenance Manual (AMM). The FAA has agreed that operators who have previously complied with ACB No. 4 are not required to perform the re-torque again. In addition, a follow-on re-torque of the brake fittings is required after completion of 100 landing cycles following the initial re-torque. I. Planning Information: Step I.A. Effectivity: Effectivity has been revised. Step I.C. Safety Intent: Information has been added concerning cockpit indications and upcoming Gulfstream action. Step I.D. Description: This bulletin has been divided into two parts with a follow-on requirement to repeat the inspection after 100 landing cyles. Step I.E. Compliance: Compliance has been included for Part II of this bulletin. Step I.F. Approval: Approval statement rewording to reflect FAA pending action. Step I.G. Manpower: Labor hour added for compliance with Part II. Step I.J. Tooling: Dial indicating torque wrench has been added to facilitate measurement of break-away torque. II. Accomplishment Instructions: Moved “RC” compliance note to beginning of sectionStep II.C. Added step to measure and record break-away torque while loosening selfsealing coupling. Revised instructions on loosening procedure Step II.D. Revised instructions to conform to recent AMM revision III. Accomplishment Instructions: Added Part II Figure 1 Revised brake fitting nomenclature to conform to recent AMM revision.

Effect of Revision on Prior Accomplishment :
This customer bulletin revision replaces ACB 4, dated November 6, 2015. Aircraft operators who have previously complied with ACB 4, dated November 6, 2015, are in compliance with Part I of this revision and should return the Part I servic e reply card marked “Previously complied with.” Part II must be performed following completion of 100 landing cycles after compliance with ACB 4, dated November 6, 2015, or Part I of this bulletin.

# TRANSMITTAL SHEET

November 13, 2015 Transmittal Page 2 Note: This customer bulletin has been reproduced in its entirety. A black bar in the left margin indicates a change in that line of text or figure.

List of Effective Pages:
Page No. Date 1 - 5 November 13, 2015

Revision History: Original Issue: November 6, 2015 Revision A: November 13, 2015

# ALERT

NUMBER 4A

LANDING GEAR (ATA 32)

INSPECTION – BRAKE INLET SELF-SEALING COUPLINGS TORQUE

NOVEMBER 13, 2015Gulfstream G650 Alert Customer Bulletin No. 4A “November 13, 2015”

Page 1 of 5 Landing Gear (ATA 32), Inspection – Brake Inlet Self-Sealing Couplings Torque

I. Planning Information: A. Effectivity: Aircraft serial numbers 6001, 6003 through 6163 Affected aircraft that have previously complied with Alert Customer Bulletin No. 4, dated November 6, 2015, titled Landing Gear (ATA 32), Inspection – Brake Inlet Self-Sealing Couplings Torque, are only affected by Part II of this bulletin.
B. Reason: Self-sealing couplings on the brake inlet fitting have been found backed out of the fullyseated position. Due to the function of these couplings, this condition can allow the selfsealing mechanism to activate and cut off hydraulic pressure to the brake caliper, resulting in no braking on the affected wheel while brake pressure indications remain normal on cockpit indications. C. Safety Intent: Inadequate torque on the self-sealing coupling may allow it to back off over time, actuating the self-sealing function. This will result in loss of hydraulic pressure to the affected brake, disabling braking action and de-spin function. Multiple coupling failures may lead to loss of braking capability on more than one wheel creating potential for reduced aircraft braking effectiveness. Since cockpit brake pressure indications are normal, the crew will have no indications prior to take-off, followed by an amber wheel de-spin Crew Alerting System (CAS) message after gear retraction. Gulfstream will be issuing a Quick Reference Handbook (QRH) revision to provide flight crews with updated procedures intended to mitigate a wheel de-spin CAS message until a design change can be implemented. D. Description: This customer bulletin is divided into two parts. Part 1 is a one-time action to perform a breakaway check and re-torque of the brake inlet self-sealing couplings on affected aircraft. Part II is a repetition of the Part I inspection to be performed 100 landing cycles after compliance with either the original issue of ACB No. 4, dated November 6, 2015, or Part I of this bulletin. E. Compliance: Compliance with Part I of this customer bulletin is required within 30 days from the original issue date of November 6, 2015, for aircraft that have not previously complied with Alert Customer Bulletin No. 4, issue date as stated. Compliance with Part II of this customer bulletin is required at the completion of 100 landing cycles following compliance with either the original issue of ACB No. 4, dated November 6, 2015, or Part I of this bulletin. F. Approval: This customer bulletin has been reviewed and approved by the Federal Aviation Administration and is the subject of pending Airworthiness Directive regulatory action.Gulfstream G650 Alert Customer Bulletin No. 4A “November 13, 2015”

Page 2 of 5 G. Manpower: Part I Inspection - 2 labor hours Part II Inspection - 2 labor hours
NOTE: Labor hours may vary due to aircraft configuration or mechanical difficulty.
H. Material:
None
I. References: G650 Aircraft Maintenance Manual (AMM), Chapters 20 and 32
NOTE: All references in this document are intended to be inclusive of any amendments or revisions unless otherwise stated. J. Tooling/Equipment:

 Standard aircraft maintenance tools

 Torque wrench, dial indicating, 0 – 300 inch-pounds GSE5101082 or equivalent.

 Torque wrench, 200 – 1000 inch-pounds, GSE5100722 or equivalent


### K. Warranty Coverage – Component: Labor and material will be at no charge if the aircraft is within the component warranty period as of the original issue date of this customer bulletin and work is accomplished within the recommended compliance time, as stated in this document, at a Gulfstream G650 Authorized Warranty Facility or Factory Authorized Service Center.* *Coverage is granted per the terms and conditions of the Gulfstream Aircraft Sales Agreement to the original purchaser or subsequent owner with appropriate Assignment of Warranties on file with Gulfstream.
NOTE: Additional labor hours incurred due to aircraft configuration or mechanical difficulties must be charged as a separate discrepancy and submitted for warranty consideration. L. Weight and Balance:
N/AGulfstream G650 Alert Customer Bulletin No. 4A “November 13, 2015”

Page 3 of 5 II. Part I Accomplishment Instructions:
CAUTION: PROTECT WIRE BUNDLES, CONNECTORS AND SURROUNDING STRUCTURE DURING ANY MAINTENANCE PROCEDURE FROM SHAVINGS, DEBRIS AND CONTAMINATION. MAINTAIN A PROPERLY CLEANED WORK AREA THROUGHOUT THE PROCEDURE TO ENSURE THE INTEGRITY OF THE AFFECTED COMPONENT / SYSTEM. VISUALLY INSPECT WORK AREA USING ADDITIONAL LIGHT AS NECESSA RY TO VERIFY ABSENCE OF ANY DEBRIS PRIOR TO COMPLETION OF PROCEDURE. FAILURE TO COMPLY MAY RESULT IN DAMAGE TO COMPONENTS AND / OR SYSTEMS.
NOTE: Some steps in the accomplishment instructions are identified as Required for Compliance (RC). If this CB is mandated by an airworthiness directive (AD), the steps identified as RC must be done to comply with the AD. Steps not identified with RC are recommended and may be deviated from, done as part of other actions, or done with accepted methods different from those given in the CB, if the RC steps can be done and the aircraft can be put back in service in a serviceable condition.
A. Prepare the aircraft for safe maintenance. Refer to AMM, Safe Ground Maintenance Procedure, Chapter 20.
WARNING: FAILURE TO INSTALL ALL LANDING GEAR AND LANDING GEAR DOOR SAFETY DEVICES BEFORE WORKING IN ANY WHEEL WELL MAY RESULT IN SERIOUS INJURY OR DEATH.
B. Gain access to the brake assemblies located on the main landing gear. See Figure 1.
C. RC – Using torque wrench, GSE5101082 or equivalent, loosen the self-sealing coupling from each brake caliper reducer fitting. Meas ure the breakaway torque and record it on the service reply card.
NOTE: Backup wrench is required to prevent loosening of the reducer fitting.
NOTE: Do not loosen the coupling enough to allow the fitting to leak, this will allow air into the system, requiring bleeding of the affected brake caliper. Loosen only until the torque wrench reads a stable value at or near 0 inch-pounds.
D. RC - Using torque wrench, GSE5100722 or equivalent, torque the self-sealing couplings on the brake caliper fitting to 215 – 285 inch-pounds at all four brake calipers. See Figure 1, Detail A. Torque the coupling flat closest to the caliper fitting. Backup wrench is required to prevent overtorquing of the reducer fitting during torque application.
E. Ensure work area is clean and clear of foreign objects (FOD).
F. Record compliance with this customer bulletin in the aircraft’s permanent maintenance records and return aircraft to flight status.
G. Report compliance with this customer bulle tin to Gulfstream Computerized Maintenance Program (CMP) by uploading the attached se rvice reply card, along with the CMP task card(s) sign-off using MyGulfstream, My CMP Document Upload or e-mail to cmp.docproc@gulfstream.com or fax to Gulfstream CMP at 800-944-1775 or 912-963-0265

. If technical assistance is required, contact your area Gulfstream Field Service Representative or call Gulfstream Customer Support at 800-810-GULF (4853) or 912-965-4178 (fax 912-965-4184).Gulfstream G650 Alert Customer Bulletin No. 4A “November 13, 2015”

Page 4 of 5 III. Part II Accomplishment Instructions:
CAUTION: PROTECT WIRE BUNDLES, CONNECTORS AND SURROUNDING STRUCTURE DURING ANY MAINTENANCE PROCEDURE FROM SHAVINGS, DEBRIS AND CONTAMINATION. MAINTAIN A PROPERLY CLEANED WORK AREA THROUGHOUT THE PROCEDURE TO ENSURE THE INTEGRITY OF THE AFFECTED COMPONENT / SYSTEM. VISUALLY INSPECT WORK AREA USING ADDITIONAL LIGHT AS NECESSA RY TO VERIFY ABSENCE OF ANY DEBRIS PRIOR TO COMPLETION OF PROCEDURE. FAILURE TO COMPLY MAY RESULT IN DAMAGE TO COMPONENTS AND / OR SYSTEMS.
NOTE: Some steps in the accomplishment instructions are identified as Required for Compliance (RC). If this CB is mandated by an airworthiness directive (AD), the steps identified as RC must be done to comply with the AD. Steps not identified with RC are recommended and may be deviated from, done as part of other actions, or done with accepted methods different from those given in the CB, if the RC steps can be done and the aircraft can be put back in service in a serviceable condition.
A. Prepare the aircraft for safe maintenance. Refer to AMM, Safe Ground Maintenance Procedure, Chapter 20.
WARNING: FAILURE TO INSTALL ALL LANDING GEAR AND LANDING GEAR DOOR SAFETY DEVICES BEFORE WORKING IN ANY WHEEL WELL MAY RESULT IN SERIOUS INJURY OR DEATH.
B. Gain access to the brake assemblies located on the main landing gear. See Figure 1.
C. RC – Using torque wrench, GSE5101082 or equivalent, loosen the self-sealing coupling from each brake caliper reducer fitting. Meas ure the breakaway torque and record it on the service reply card.
NOTE: Backup wrench is required to prevent loosening of the reducer fitting.
NOTE: Do not loosen the coupling enough to allow the fitting to leak, this will allow air into the system, requiring bleeding of the affected brake caliper. Loosen only until the torque wrench reads a stable value at or near 0 inch-pounds.
D. RC - Using torque wrench, GSE5100722 or equivalent, torque the self-sealing couplings on the brake caliper fitting to 215 – 285 inch-pounds at all four brake calipers. See Figure 1, Detail A. Torque the coupling flat closest to the caliper fitting. Backup wrench is required to prevent overtorquing of the reducer fitting during torque application.
E. Ensure work area is clean and clear of foreign objects (FOD).
F. Record compliance with this customer bulletin in the aircraft’s permanent maintenance records and return aircraft to flight status.
G. Report compliance with this customer bulle tin to Gulfstream Computerized Maintenance Program (CMP) by uploading the attached se rvice reply card, along with the CMP task card(s) sign-off using MyGulfstream, My CMP Document Upload or e-mail to cmp.docproc@gulfstream.com or fax to Gulfstream CMP at 800-944-1775 or 912-963-0265

. If technical assistance is required, contact your area Gulfstream Field Service Representative or call Gulfstream Customer Support at 800-810-GULF (4853) or 912-965-4178 (fax 912-965-4184).Gulfstream G650 Alert Customer Bulletin No. 4A “November 13, 2015”

Page 5 of 5 Brake Assembly (Typical) 

## Figure 1Gulfstream G650 Alert Customer Bulletin No. 4A “November 13, 2015”

Customer Bulletin prepared by Gulfstream Aerospace, 500 Gulfstream Road, P.O. Box 2206, Savannah, Georgia 31402-2206, USA.
© 2015 Gulfstream Aerospace All rights reserved, including the right to reproduce this pub lication. No part may be reproduced, stored in any retrieval syst em, or transmitted in any part or form or by any means, electronic, photocopying, micr ofilm, microfiche, mechanical, or otherwise, without prior written permission of Gu lfstream Aerospace.

This technical data is controlled under the Ex port Administration Regulations by General License TSU. It may not be transferre d to a third party without the prior written approval of the U.S. Department of Commerce.

GA 611A 2/97 

## Part I Service Reply Card
Please upload this page, along with the CMP task card(s) sign-off using MyGulfstream, MyCMP Document Upload, or e-mail to cmp.docproc@gulfstream.com or fax to Gulfstream CMP at 800- 944-1775 or 912-963-0265.
The following Alert Customer Bulletin (ACB) has been addressed:

CB Number A/C A/C Type Compliance Date

990041 G650

Aircraft Hours Aircraft Landings

This Customer Bulletin is not applicable because:
Serial Number not affected Equipment not installed ______Previously complied with (annotate method of compliance below) ______Other (explain reason below)

Record Breakaway Torque:

Left Outboard (#1) Left Inboard (#2) Right Inboard (#3) Right Outboard (#4)

Signature Title/Certificate Number Company
Comments / Suggestions:Gulfstream G650 Alert Customer Bulletin No. 4A “November 13, 2015”

Customer Bulletin prepared by Gulfstream Aerospace, 500 Gulfstream Road, P.O. Box 2206, Savannah, Georgia 31402-2206, USA.
© 2015 Gulfstream Aerospace All rights reserved, including the right to reproduce this pub lication. No part may be reproduced, stored in any retrieval syst em, or transmitted in any part or form or by any means, electronic, photocopying, micr ofilm, microfiche, mechanical, or otherwise, without prior written permission of Gu lfstream Aerospace.

This technical data is controlled under the Ex port Administration Regulations by General License TSU. It may not be transferre d to a third party without the prior written approval of the U.S. Department of Commerce.

GA 611A 2/97 

## Part II Service Reply Card
Please upload this page, along with the CMP task card(s) sign-off using MyGulfstream, MyCMP Document Upload, or e-mail to cmp.docproc@gulfstream.com or fax to Gulfstream CMP at 800- 944-1775 or 912-963-0265.
The following Alert Customer Bulletin (ACB) has been addressed:

CB Number A/C A/C Type Compliance Date

990042 G650

Aircraft Hours Aircraft Landings

This Customer Bulletin is not applicable because:
Serial Number not affected Equipment not installed ______Previously complied with (annotate method of compliance below) ______Other (explain reason below)

Record Breakaway Torque:

Left Outboard (#1) Left Inboard (#2) Right Inboard (#3) Right Outboard (#4)

Signature Title/Certificate Number Company
Comments / Suggestions: