SERVICE BULLETIN

SUBJECT

 

 

 ALERT 

NUMBER 150-28A-146 

 FUEL (ATA 28) - INSPECTION OF LEFT AND 

RIGHT WING INBOARD VENT HOLES 

JUNE 22, 2012 
Gulfstream.............................................

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 1 of 15

FUEL - INSPECTION OF LEFT AND RIGHT WING INBOARD VENT HOLES 

PLANNING INFORMATION

202

1. Effectivity

Aircraft serial numbers 201-290

2. Concurrent Requirement

None

3. Reason

Recent inspection of a G150 aircraft following flight revealed several fasteners 

protruding from the lower wing surface. Initial investigation of the wing interior revealed 

several structural rib assemblies damaged and separated from the wing plank. Further 

investigation has revealed the wing vent tube covered with sealant, essentially blocking 

the path for air to exit the wing during fueling operations and thermal expansion. 

Continued operation in this condition has the potential to compromise the integrity of 

the wing structure. The potential exists for this condition to be present on other aircraft. 

4. Description

This alert service bulletin provides instructions to inspect the 3/8 inch vent holes 

outboard of rib zero for debris or obstructions. Method 1 requires defueling of the wing 

and internal inspection, Method 2 may be performed only if the aircraft has 3000 

pounds or less total fuel on board.

5. Compliance

Compliance with this alert service bulletin is mandatory before further flight. 

6. Approval

This service bulletin contains no modification information that revises the approved 

configuration and therefore does not require regulatory agency approval.

7. Manpower

The following information is for planning purposes only:

Estimated man-hours (Method 1): 12

Estimated man-hours (Method 2): 16

June 22, 2012
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 2 of 15

8. Weight and Balance

None

9. Electrical Load Data

No Change

10. Software Accomplishment Summary

None

11. References

G150 Aircraft Maintenance Manual (AMM) Chapters 06, 12, 20 and 28 

12. Other Publications Affected

None

13. Interchangeability or Intermixability of Parts

None

June 22, 2012
Gulfstream.............................................

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 3 of 15

MATERIAL INFORMATION

1. Material - Price and Availability

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

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

2. Opportunity for No Charge Compliance

This alert service bulletin will be accomplished at no charge if performed at a 

Gulfstream G150 Authorized Warranty Repair Facility within the recommended 

compliance time stated in this document. If this alert service bulletin is performed at 

other than a Gulfstream G150 Authorized Warranty Repair Facility, the labor will be an 

owner responsibility.

3. Material Necessary for Each Aircraft

A. Material to be Procured:

None

B. Materials Supplied by the Operator:

None

4. Reidentified Parts

None

5. Special Tooling

Borescope

Lockwire, P/N MS20995C.032

Flash light (Strong light)

Mirror

Petroleum jelly

Torque wrench 0.0 to 50 inch-lbs.

June 22, 2012
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 4 of 15

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 Aircraft Maintenance Manual, 

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 Aircraft Maintenance 

Manual, Chapter 12.

3. Perform Inspection in accordance with method 1 or method 2 below. 

4. Inspection Method 1 (refer to Figure 1, Sheets 1, 2 and Figure 4, Sheets 1 and 2):

A. Defuel aircraft. Refer to AMM, Chapter 12.

B. Remove left wing access panel 521AB. Refer to Figure 1, Sheet 1 and AMM, 

Chapter 06.

C. Remove right wing access panel 621AB. Refer to Figure 1, Sheet 2 and AMM, 

Chapter 06.

D. Perform a detailed visual inspection (using a strong flash light and mirror) of the 

3/8 inch vent holes for debris or obstruction located outboard of rib zero, 

internal-wing upper surface in the left and right wing. Refer to Figure 3, Sheets 1 

and 2.

E. The wing vent holes should be clear and free of any debris or obstructions. Refer 

to Figure 3, Sheets 1 and 2.

F. If no defects or other anomalies are noted and vent holes are clear and free of 

debris or sealant, no further action is required. Proceed to Step 4.H. below. 

June 22, 2012
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 5 of 15

G. If any defects or any other anomalies are present, or vent openings are 

covered/sealed, contact Gulfstream Customer Support at 800-810-4853 or 

912-965-4178 for further instructions.

H. Reinstall left wing access panels 521AB. Refer to Figure 1, Sheet 1 and AMM, 

Chapter 06.

I. Reinstall right wing access panel 621AB. Refer to Figure 1, Sheet 2 and AMM, 

Chapter 06.

J. If aircraft was defueled for inspection, refuel aircraft. Refer to AMM, Chapter 12.

5. Inspection Method 2 (refer to Figure 2 and Figure 3, Sheets 1 and 2): 

CAUTION: INSPECTION METHOD 2 MAY ONLY BE PERFORMED WITH TOTAL 

AIRCRAFT FUEL LEVEL BELOW 3000 POUNDS. 

A. Remove the left and right wing - to - fuselage fairings, P/N 

25G3621110-503/-504. Refer to Figure 2.

B. Cut lockwire and disconnect B-nut fittings from union. Refer to Figure 3, Sheets 1 

and 2. 

C. Remove as necessary clamps, screws and washers securing wing vent relief 

tube to the support structure.

D. Using a borescope, inspect vent hole by inserting boroscope through fitting tube 

assembly, P/N 25G6537225-501. Inspect for debris/sealant blockage at wing 

vent orifice. 

E. If no defects or other anomalies are noted and vent hole is clear and free of 

debris or sealant, no further action is required.

F. If any defects or any other anomalies are present, or vent opening is 

covered/sealed, contact Gulfstream Customer Support at 800-810-4853 or 

912-965-4178 for further instructions. 

G. Repeat Steps 5.A. through 5.F. for right side vent tube.

H. Connect B-nut fittings to left and right unions. Refer to Figure 3, Sheets 1 and 2. 

I. Tighten B-nut fittings to left and right unions and secure with lockwire, P/N 

MS20995C.032

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

June 22, 2012
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 6 of 15

7. Reinstall the left and right wing - to - fuselage fairings, P/N 25G3621110-503/-504. 

Refer to Figure 2 and Figure 5, Sheets 1 and 2.

NOTE: In order to allow correct and smooth installation of the fairing, it is critical to 

secure holding bolts in a sequence beginning with all horizontal central 

holes and then in an up and down horizontal sequence. Refer to Figure 5, 

Sheets 1 and 2. 

8. Dip all bolt threads in petroleum jelly and secure fairing using bolts (1, 3, 5 and 7), per 

the locations depicted in Figure 5, Sheet 1. Torque bolts to 20-25 inch-lb. (refer to 

Figure 5, Sheet 2 for torque sequence). 

9. Record compliance with this alert service bulletin in the aircraft’s permanent 

maintenance record.

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

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

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). 

June 22, 2012
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 7 of 15

Left Wing Access Panel 521AB

Figure 1, Sheet 1

June 22, 2012

521AB
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 8 of 15

ACCESS PANEL 621AB

Right Wing Access Panel 621AB

Figure 1, Sheet 2

June 22, 2012
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 9 of 15

Left Wing - to - Fuselage Fairing; Right Side Opposite

Figure 2

June 22, 2012

WING - TO - FUSELAGE FAIRING

LEFT SIDE SHOWN; RIGHT

SIDE OPPOSITE
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 10 of 15

REMOVE B-NUT FITTING AND

INSERT BORESCOPE PROBE

LEFT VENT TUBE ASSEMBLY, P/N

RIGHT VENT TUBE ASSEMBLY,

CUT LOCKWIRE FROM UNIO,

LEFT VENT TUBE ASSEMBLY, P/N 25G6537225-501 SHOWN;

RIGHT SIDE OPPOSITE

SEE DETAIL A

25G6544683-501 SHOWN

DETAIL A

WING FITTING ASSEMBLY, 

P/N 25G6537225-501

(SAME P/N ON LEFT AND 

RIGHT WING)

P/N 25G6544683-502

Left Wing Vent Fitting; Right Side Opposite

Figure 3, Sheet 1

June 22, 2012
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 11 of 15

Left Wing Vent Fitting; Right Side Opposite

Figure 3, Sheet 2

June 22, 2012

LEFT VENT TUBE ASSEMBLY, P/N 25G6537225-501 SHOWN,

RIGHT SIDE OPPOSITE

CUT LOCKWIRE FROM UNION,

REMOVE B-NUT FITTING AND

INSERT BORESCOPE PROBE

HERE

SEE DETAIL B

DETAIL B
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 12 of 15

Example of Vent Shown with no Sealant (Correct)

Figure 4, Sheet 1

June 22, 2012

RIGHT SIDE SHOWN; LEFT SIDE OPPOSITE
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 13 of 15

Example of Vent Shown Covered with Sealant (Incorrect)

Figure 4, Sheet 2

June 22, 2012

LEFT SIDE SHOWN; RIGHT SIDE OPPOSITE
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 14 of 15

Fuselage Fairing Bolt Locations

Figure 5, Sheet 1

June 22, 2012
Gulfstream

ALERT SERVICE BULLETIN

Service Bulletin No. 150-28A-146

Page 15 of 15

Fuselage Fairing Bolt Torque Sequence

Figure 5, Sheet 2

June 22, 2012
GULFSTREAM G150 

ALERT SERVICE BULLETIN NO. 150-28A-146 

SERVICE REPLY CARD

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

31402-2206, USA. © 2012 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

981460 Gulfstream G150 

AIRCRAFT HOURS: AIRCRAFT LANDINGS: 

PREVIOUSLY COMPLIED 

WITH: DATE: 

NOT APPLICABLE: DATE: 

 

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