# Gulfstream Customer Bulletin 250: No revision named - Rights: © Gulfstream Aerospace Corporation. Filed by the FAA in regulations.gov docket FAA-2022-1486; AD 2023-08-03 incorporates this document by reference. Not covered by OpenAirDocs’ CC0 dedication. - Document: [Gulfstream Customer Bulletin 250](https://openairdocs.org/service-documents/gulfstream/cb-250.md) - Title as filed: G400 CB 250 - Pages: 5 - PDF: https://openairdocs.org/files/sha256/40/a9/40a910f14f3ef04946ca691271d56575b574e0f99c3a6905bbf415a4c3e0f358 - Page: https://openairdocs.org/service-documents/gulfstream/cb-250/file/40a910f14f3e ## Text Each page's text from the PDF; open the PDF at a page with #page=N. ### Page 1 CUSTOMER BULLETIN No. 250 SUBJECT FLIGHT CONTROLS (ATA 27) MODIFICATION – GROUND SPOILER HYDRAULIC LINE (ASC-489) Initial Issue November 9, 2022 ### Page 2 CUSTOMER BULLETIN November 9, 2022 Customer Bulletin No. 250 Page 1 of 3 Flight Controls (ATA 27), Modification – Ground Spoiler Hydraulic Line (ASC-489) I. Planning Information: A. Effectivity: Aircraft serial numbers 1000-1535 B. Concurrent Requirements: This customer bulletin requires incorporation of GI V Aircraft Service Change (ASC) 489, Flight Controls (ATA 27) Ground Spoiler Hydraulic Line – Modification. C. Reason: It has been discovered that when performing maintenance on the ground spoiler actuator, it is possible to improperly connect ( cross connect) the G round Spoiler (GS) signal line and the combined hydraulic pressure (P1) line at the actuator. Failure to connect the hydraulic lines to the proper actuator ports can result in improper operation of the ground spoilers, including asymmetrical deployment and operation during flight, potentially leading to loss of control of the aircraft. To address this condition, Gulfstream has developed ASC 489, Flight Controls (ATA 27) Ground Spoiler Hydraulic Line – Modification, which changes the design of the GS signal line to incorporate a new actuator union fitting to increase the interface from a -4 to a -5, and a new hose with a - 5 connector to match the new union fitting. This solution physically prevents improper hydraulic line connection. D. Safety Intent: The safety intent of this CB is to prevent future improper connection of the ground spoiler hydraulic lines during maintenance. Failure to properly connect the hydraulic lines to the ground spoiler actuator can result in improper operation of the ground spoilers, including asymmetrical deployment and operation during flight, potentially leading to loss of control of the aircraft. E. Configuration Description: Incorporating ASC 489 will result in installing a new GS signal line and union fitting to increase the connection size from -4 to -5 which physically prevents improper line connection. F. Description: This customer bulletin is a one -time action to incorporate G 400 ASC 489, Flight Controls (ATA 27) Ground Spoiler Hydraulic Line – Modification, initial issue dated November 9, 2022. G. Compliance: Compliance with this customer bulletin is required by August 31, 2024. H. Approval: The engineering aspects of this customer bulletin have been reviewed and approved by the Federal Aviation Administration, and are the subject of pending Airworthiness Directive regulatory action. I. Labor Requirements: Refer to ASC 489 J. Weight and Balance: Refer to ASC 489 ### Page 3 CUSTOMER BULLETIN November 9, 2022 Customer Bulletin No. 250 Page 2 of 3 K. References: Aircraft Maintenance Manual (AMM), Chapters 20 and 27 G400 ASC 489, Flight Controls (ATA 27) Ground Spoiler Hydraulic Line – Modification, initial issue dated November 9, 2022. NOTE: All references in this document are intended to be inclusive of any amendments or revisions unless otherwise stated. L. Publications Affected: Refer to ASC 489 II. Material Information: A. Material - Availability: Refer to ASC 489 B. Warranty Coverage: Material will be provided at no charge regardless of warranty status. Labor cost for installation will be at operator’s expense. C. Material Necessary for Each Aircraft: 1. Material to be Procured Refer to ASC 489 2. Material Supplied by Operator Refer to ASC 489 D. Re-identified Parts: Refer to ASC 489 E. Special Equipment / Tools Required: Refer to ASC 489 ### Page 4 CUSTOMER BULLETIN November 9, 2022 Customer Bulletin No. 250 Page 3 of 3 III. 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 NECESSARY TO VERIFY ABSENCE OF ANY DEBRIS PRIOR TO COMPLETION OF PROCEDURE. FAILURE TO COMPLY MAY RESULT IN DAMAGE TO COMPONENTS AND / OR SYSTEMS. NOTE: S ome 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 returned to a serviceable condition. A. Prepare the aircraft for safe maintenance. B. (RC) Incorporate G 400 ASC 489, Flight Controls (ATA 27) Ground Spoiler Hydraulic Line – Modification, initial issue dated November 9, 2022. C. Ensure work area is clean and clear of foreign objects (FOD). D. Record compliance with this customer bulletin in the aircraft permanent maintenance records and return aircraft to flight status. E. Report compliance with this service bulletin to Gulfstream Computerized Maintenance Program (CMP) by uploading the attached service reply card, along with the CMP task card(s) sign- off using MyGulfstream, MyCMP Document Upload, e-mail to fax @campsystems.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). ### Page 5 CUSTOMER BULLETIN PROPRIETARY NOTICE: These materials include proprietary information and data of Gulfstream Aerospace Corporation. Unauthorized distribution is strictly prohibited. © 2022 Gulfstream Aerospace Corporation. All rights reserved. EAR EXPORT CONTROLLED WARNING: This document contains technical data that is subject to U.S. Export Controls. Release to foreign persons, export transfer or re-export of this technical data requires approval from the Department of Commerce. SERVICE REPLY CARD Please upload this page, along with the CMP task card(s) sign- off using MyGulfstream, MyCMP Document Upload, e-mail to fax@campsystems.com or fax to Gulfstream CMP at 800-944-1775 or 912-963-0265. THE FOLLOWING CUSTOMER BULLETIN HAS BEEN COMPLIED WITH: 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) Signature Title/Certificate Number Company Comments / Suggestions: CB NO. CMP CODE ACFT SERIAL NO. COMPLIANCE DATE 250 982500 --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain, except the copies of manufacturers’ service documents, which belong to their rights holders.