SUBJECT

SERVICE BULLETIN

 

NUMBER 100-28-297 

FUEL (ATA 28) – MAIN LANDING GEAR 

WHEEL WELL FUEL LINES - INSPECTION AND 

ADDITION OF LOOP CLAMPS BETWEEN FUEL 

LINES AND ELECTRICAL HARNESSES 

JANUARY 21, 2010 
Gulfstream

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 1 of 12

FUEL - MAIN LANDING *($5WHEEL WELL FUEL LINES - INSPECTION AND ADDITION OF 

LOOP CLAMPS BETWEEN FUEL LINES AND ELECTRICAL HARNESSES

PLANNING INFORMATION

100-28-297

1. Effectivity

Aircraft serial numbers 004 and 011 through 158

2. Concurrent Requirement

None

3. Reason

Recently, a G100 operator reported that remnants of sponge-rubber padding were 

found attached by cable tie-wraps to the fuel lines in the Main Landing Gear (MLG) 

wheel well. This padding is not approved for installation and was not intended to 

provide clearance / separation between the fuel lines and electrical harnesses. In 

addition, under some cable tie-wraps, corrosion was present, caused by moisture 

being trapped within the open sponge rubber shells.

4. Description

This service bulletin provides instructions to remove the sponge-rubber padding from 

the fuel lines, inspect for corrosion, and treat and / or replace damaged fuel lines as 

required. Additionally, instructions are provided to install loop clamps to achieve a 

minimum clearance of 0.5 inches (12.7 mm), between the fuel lines and electrical 

harnesses.

5. Compliance

Compliance with this service bulletin is mandatory at the next suitable planned 

maintenance period within 24 months. 

6. Approval

This service bulletin has been reviewed by the Civil Aviation Administration of Israel 

(CAAI). The design content herein complies with the applicable Civil Aviation 

Regulations and is CAAI approved.

January 21, 2010
Gulfstream

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 2 of 12

7. Manpower

The following information is for planning purposes only:

Estimated man-hours: 4 for inspection

14 for corrosion treatment if necessary 

7 for clamping procedure if necessary

NOTE: Fuel line replacement if required, is not inclusive and will be quoted by the 

installing facility. 

8. Weight and Balance

None

9. Electrical Load Data

No Change

10. Software Accomplishment Summary

None

11. References

Astra, Astra SPX and G100 Aircraft Maintenance Manual (AMM), Chapters 20, 24 

and 28

Gulfstream Aerospace LP Modification G1-10031

NOTE: The design of MOD G1-10031 is configured to a standard type certificated 

configuration aircraft. Approval, by the local regulatory authority, of any 

deviation from the instructions contained in this service bulletin must be 

obtained, if required, in accordance with the relevant local regulations.

12. Other Publications Affected

Astra, Astra SPX and G100 AMM, Chapter 28 

Astra, Astra SPX and G100 Illustrated Parts Catalog (IPC), Chapter 28

NOTE: Data concerning this service bulletin will be published in a future revision of 

the affected manual(s). This service bulletin will provide technical data until 

the revisions are published.

13. Interchangeability or Intermixability of Parts

None

January 21, 2010
Gulfstream

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 3 of 12

MATERIAL INFORMATION

14. Material - Price and Availability

The parts required to accomplish this service bulletin are available by contacting

Spare Parts Sales at 800-810-GULF (4853) or 912-965-4178.

15. Warranty Coverage - Component

None

16. Material Necessary for Each Aircraft

NOTE: The parts listed in this section can be substituted with equivalent Israel 

Aerospace Industries (IAI) approved parts. If equivalent part(s) is used, it 

must be accompanied by documentation from IAI stating equivalence.

A. Material to be Procured:

NOTE: MS21919WCF clamps may be substituted for AS21919WCF clamps.

B. Materials Supplied by Operator:

Abrasive Paper #400 grit or Scotch-Brite types 7447 (Rough) and 7448 (Fine) or 

equivalent

Acetone

Alodine 1200S or equivalent

Fluid-resistant epoxy primer-class 2, per BMS 10-11, type 1

New Part No. Keyword Old Part No. Qty.

AS21919WCF04 Loop Clamp - A/R

AS21919WCF05 Loop Clamp - A/R

AS21919WCF16 Loop Clamp - A/R

AS21919WCF20 Loop Clamp - A/R

AS21919WCF24 Loop Clamp - A/R

NAS1149C0332R Flat Washer - A/R

MS27039C1-09 Screw - A/R

MS21042L3 Nut - A/R

TA4070M0808 90 Deg. Bracket - A/R

January 21, 2010
Gulfstream 

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 4 of 12

17. Reidentified Parts

None

18. Special Tooling

Concave mirror or a 10 X magnifying glass

Digital handheld ultrasonic thickness gauge or equivalent

January 21, 2010
Gulfstream

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 5 of 12

ACCOMPLISHMENT INSTRUCTIONS

CAUTION: PROTECT WIRE BUNDLES, CONNECTORS AND SURROUNDING 

STRUCTURE DURING ANY MAINTENANCE PROCEDURES 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.

1. Prepare aircraft for safe maintenance. Refer to AMM, Safe Ground Maintenance 

Procedure, Chapter 20.

CAUTION: MAKE SURE ELECTRICAL POWER IS DISCONNECTED FROM AIRCRAFT. 

FAILURE TO COMPLY MAY RESULT IN INJURY TO PERSONNEL AND/OR 

DAMAGE TO AIRCRAFT.

2. Disconnect external electrical power from aircraft. Refer to AMM, Chapter 24.

3. Remove left and right MLG doors (16 and 16A) to gain access to the fuel 

lines listed below. Refer to AMM, Chapter 28 and Figure 1:

4. Rework Procedure:

A. Perform detailed inspection for presence of sponge-rubber padding in the wheel

well area, particularly on the fuel lines noted in Step 3. Refer to Figure 2.

(1) If sponge-rubber is present, perform the following (refer to Figure 2,

Sheet 1):

(a) Document the sponge-rubber with a digital camera. Send photos to 

Gulfstream Customer Support via email at 

midcabin.techops@gulfstream.com

P/N Description and Function DIA. X Wall Thk.

25W653120-539/-540 Wing tank vent - line connection from the

fuselage to the bladder tank

1.00” x 0.035”

25W653120-637/-638 Main vent - line connection from the fuselage

bladder tank to the NACA scoop

1.50” x 0.035”

25W653120-639/-640 Transfer line from the fuselage bladder tank to

the wing tank

1.25” x 0.035”

January 21, 2010
Gulfstream 

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 6 of 12

(b) Cut all the cable tie-wraps attaching the sponge-rubber padding to the

fuel lines.

(c) Remove and dispose of cable-tie wraps and remnants of padding.

NOTE: If there are any other fuel lines besides those indicated

above that are also wrapped with sponge-rubber, remove the

sponge-rubber from all affected fuel lines.

(2) Perform a detailed visual inspection for corrosion on the fuel lines in the

areas where sponge-rubber has been used and perform the following

as necessary (refer to Figure 2, Sheet 2):

(a) Remove corrosion using abrasive paper #400 grit or 3M Scotch-Brite

Types 7447 (Rough) and 7448 (Fine) or equivalent. Blend the

surrounding area to a ratio of 10:1 to the depth of the corrosion

removed.

(b) Clean the reworked area with acetone and wipe dry.

(c) Ensure that all corrosion has been removed using a concave mirror or a 

ten (10) X magnifying glass.

(3) Measure the wall thickness of areas where corrosion has been removed 

using a digital handheld ultrasonic thickness gauge or equivalent.

(a) Replace any tubes if the minimum thickness is less than follows (refer 

to IPC, Chapter 28 and AMM, Chapter 28):

1 0.028” for tubes with a nominal thickness of 0.035” 

(P/Ns 25W653120-539/-540/-637/-638/-639/-640).

2 For others tubes in the immediate area that may have corrosion 

spots but with wall thickness of 0.028” rework to a minimum 

thickness of 0.022”.

B. Treat reworked areas with Alodine type 1200S or equivalent.

C. Apply fluid-resistant epoxy primer-class 2, per BMS 10-11, type 1, to reworked 

areas.

5. Clamping procedure:

NOTE: Inspect the fuel lines and electrical harnesses for separation as depicted in 

Figure 3, Sheets 1 and 2. The possibility exists that some aircraft may be 

configured as shown in Figure 3. 

A. Install loop clamps (5, 6 or 7) to suit the diameters for each fuel tube. Refer to

Figure 3, Details A, B and C.

January 21, 2010
Gulfstream 

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 7 of 12

B. Install loop clamps (1 or 9) to suit the diameters for the electrical harnesses.

C. Secure the fuel line loop clamps and electrical harness loop clamps

together using screws (4), P/N MS27039C1-09, washers (2), P/N 

NAS1149C0332R and nuts (3), P/N MS21042L3.

D. Where any electrical harnesses intersect or meet fuel tubes, use bracket angle

(8), P/N TA4070M0808, to connect the loop clamps. Refer to Figure 3,

Detail C.

6. Reinstall left and right MLG doors (16 and 16A). Refer to AMM, Chapter 

28 and Figure 1.

7. Ensure work area is clean and clear of foreign objects (FOD).

8. Record compliance with this service bulletin in the aircraft’s permanent maintenance 

records and return aircraft to flight status.

9. Report compliance with this service bulletin to Gulfstream CMP via electronic 

transmittal or fill out and fax the attached service reply card. 

NOTE: When reporting compliance with this service bulletin, ensure the 

questionnaire table within the service reply card is annotated. 

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).

January 21, 2010
Gulfstream 

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 8 of 12

Landing Gear Access Doors

Figure 1

January 21, 2010
Gulfstream 

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 9 of 12

REMNANTS OF

SPONGE-RUBBER

PADDING

TYPICAL REMNANTS OF SPONGE-RUBBER PADDING

LEFT WHEEL WELL SHOWN RIGHT OPPOSITE

OUTBOARD

FORWARD

Wheel Well Inspection Area

Figure 2 (Sheet 1)

January 21, 2010
Gulfstream 

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 10 of 12

Wheel Well Inspection Area

Figure 2 (Sheet 2)

January 21, 2010
Gulfstream 

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 11 of 12

Installation of Clamps

Figure 3 (Sheet 1)

January 21, 2010

MINIMUM GAP 0.50 INCH

LOCATION OF CLAMPS ADDED
Gulfstream 

SERVICE BULLETIN

Service Bulletin No. 100-28-297

Page 12 of 12

MINIMUM GAP 0.50 INCH

Installation of Clamps

Figure 3 (Sheet 2)

January 21, 2010
GULFSTREAM G100 

SERVICE BULLETIN NO. 100-28-297 

SERVICE REPLY CARD 

Service Bulletin prepared by Gulfstream Aerospace, 500 Gulfstream Road, P.O. Box 2206, Savannah, Georgia 31402-2206, USA. © 

2010 Gulfstream Aerospace. All rights reserved, including the right to reproduce this publication. No part may be reproduced, stored in 

any retrieval system, or transmitted in any part or form or by any means, electronic, photocopying, microfilm, microfiche, mechanical, or 

otherwise, without prior written permission of Gulfstream Aerospace. This technical data is controlled under the Export Administration 

Regulations by General License TSU. It may not be transferred to a third party without the prior written approval of the U.S. 

Department of Commerce. 

PLEASE FAX THIS PAGE TO GULFSTREAM AEROSPACE CMP 

FAX # 800-944-1775 or 912-963-0265.

THE FOLLOWING SERVICE BULLETIN HAS BEEN COMPLIED WITH: 

SB CMP NUMBER A/C AIRCRAFT TYPE COMPLIANCE 

DATE

982970 ASTRA / ASTRA SPX / Gulfstream 

G100 

AIRCRAFT HOURS: AIRCRAFT LANDINGS: 

PREVIOUSLY COMPLIED 

WITH: DATE: 

NOT APPLICABLE: DATE: 

Sponge Rubber Installed? Yes No 

Left Wheel Well Right Wheel Well 

Corrosion Present on 

Fuel Tubes? 

Left Wheel Well Right Wheel Well 

Is Separation Between 

Fuel Tubes & Harnesses 

as Depicted in Figure 3, 

Sheets 1 & 2? 

 

Left Wheel Well Right Wheel Well 

 

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NUMBER 

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