**FUEL SYSTEM - Fuel System (73-00-00) - Introduction of Fuel Filter Differential Pressure Switch Collar** 

**GE PROPRIETARY INFORMATION** The information contained in this document is GE proprietary information and is disclosed in con fi dence. It is the property of GE and shall not be used, disclosed to others or reproduced without the express written consent of GE, including, but without limitation, it is not to be used in the creation, manufacture, development, or derivation of any repairs, modi fi cations, spare parts, designs, or con fi guration changes or to obtain FAA or any other government or regulatory approvalto do so. If consent is givenfor reproduction inwhole or in part,this notice andthe notice set forth on each page of this document shall appear in any such reproduction in whole or in part.This technical data is considered EAR controlled pursuant to 15 CFR Parts 730-774 respectively. Transfer of this data by any means to a Non-US Person, whether in the United States orabroad,withoutthe properU.S.Governmentaut horization (e.g., License, exemption,NLR, etc.), is strictly prohibited. Copyright (2011)GeneralElectric Company, U.S.A.

August 17, 2011 CT7-8 S/B 73-A0008 PAGE 1 of 8**FUEL SYSTEM - Fuel System (73-00-00) - Introduction of Fuel Filter Differential Pressure Switch Collar**  1. P LA N N I N G I N F O R M A T I O N A. E ff e ct i v i ty CT7-8/-8A/-8A1/-8A5/-8B/-8B5/-8E/-8E5/-8F/-8F5 This Alert Service Bulletin is applicable to the following engines that have a fuel differential pressure switch P/N TD028VF0H7Y5: CT7-8A engines, serial numbers 947583 and below CT7-8A1 engines, serial numbers 530019 and below CT7-8E engines, serial numbers 953076 and below CT7-8F5 engines, serial numbers 731012 and below, 817021, and 817022. This Alert Service Bulletin has been introduced in production to these CT7-8 turboshaft engines: CT7-8A engines, serial numbers 947584 and up CT7-8A1 engines, serial numbers 530020 and up CT7-8E engines, serial numbers 953077 and up CT7-8F5 engines, serial numbers 731013 and up. B. D e s c r i p t i o n This Alert Service Bulletin introduces a new collar to the differential pressure switch. The new fuel fi lter differential pressure switch collar kit, P/N 59TC02800K1T includes the collar, P/N 88TC02800000, and two (2) longer screws, P/N NAS1352C08LE12. The collar will retain the differential pressure switch, P/N TD028VF0H7Y5, from separating from the fi lter head of the fuel fi lter assembly, P/N 4110T53P06, due to cracks on fl anges. C. C o m p l i a n c e Category 2 GE recommends that you comply with this Alert Service Bulletin within 500 Hours EOT of the issuance of this bulletin, OR before December 31, 2011, whichever comes fi rst. N O T E : This Alert Service Bulletin can be accomplished on-wing and/or in shop.

August 17, 2011 CT7-8 S/B 73-A0008 PAGE 2 GE PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.**FUEL SYSTEM - Fuel System (73-00-00) - Introduction of Fuel Filter Differential Pressure Switch Collar**  D. C o n c u r re n t R e q u i r e m e n t s CT7-8 S/B 73-A0007 Once this Alert Service Bulletin is complied with, discontinue requirement of CT7-8 S/B 73-A0007, Visual Inspection for Fuel Filter Differential Pressure Switch Cracks. E. R e a s o n (1) Objective: To improve reliability and reduce signi fi cant events. (2) Condition: CT7-8 engines may display cracking across the two bolt hole fl anges of the differential pressure switch, P/N TD028VF0H7Y5. The differential pressure switch is part of the fuel fi lter assembly (P/N 4110T53P06), located on the accessory gearbox. (3) Cause: High stresses causing anodized coating to crack and associated buildup of corrosion. (4) Improvement and Inspection: If fuel fi lter differential pressure switch collar kit P/N 59TC02800K1T is not available, continue daily inspections per CT7-8 S/B 73-A0007, Visual Inspection for Fuel Filter Differential Pressure Switch Cracks. The collar assembly may be fi tted over the differential pressure switch, P/N TD028VF0H7Y5, to allow continued use without daily inspections. The collar provides support to the differential pressure switch fl anges so that retention of the differential pressure switch to the fuel fi lter assembly is maintained. (5) Substantiation: Substantiation is by analysis and test. F. A p p rova l This Service Bulletin has been reviewed by the FAA and the repair(s) and modi fi cation(s) herein comply with the applicable Federal Aviation Regulations and are FAA APPROVED for installation in the model(s) listed in this Service Bulletin. G. M a n p o w e r After you get access to the fuel fi lter assembly, you will need approximately 10 minutes to install the fuel fi lter differential pressure switch collar kit for each engine or component.

August 17, 2011 CT7-8 S/B 73-A0008 PAGE 3 GE PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.**FUEL SYSTEM - Fuel System (73-00-00) - Introduction of Fuel Filter Differential Pressure Switch Collar**  H. We i g h t a n d B a l a n ce The complete compliance with this Alert Service Bulletin increases weight by 0.1 lb (0.05 kg). I. R e f e re n c e s (Use the latest version of these documents) CT7-8 S/B 73-A0007, Visual Inspection for Fuel Filter Differential Pressure Switch Cracks GEK 105159, CT7-8 Maintenance Manual (MM) J. P u b l i c at i o n s Aff e ct e d CT7-8 Turboshaft Engine Service Record GEK 105158, CT7-8 Illustrated Parts Catalog (IPC) GEK 105159, CT7-8 Maintenance Manual (MM) K. I n t e r c h a n g e a b i l i ty Not applicable. L. S o ftw a r e A cc o m p l i s h m e n t S u m m a ry Not applicable. 2. M A T E R I A L I N F O R M A T I O N A. M at e r i a l

- P r i ce a n d Av a i l a b i l i ty (1) Parts necessary to do this Alert Service Bulletin:

P a rt N u m b e r Q ty/ E n g P a rt N a m e U n i t ( $ ) P r i c e P kg Q ty L e a d T i m e D ays 59TC02800K1T (1) Kit, Fuel Filter Differential Pressure Switch Collar Quote (-) Quote
.88TC02800000 (1) Collar Quote (-) Quote .NAS1352C08LE12 (2) Capscrew, Socket Head Quote (-) Quote
(2) Other Spare Parts: None.

August 17, 2011 CT7-8 S/B 73-A0008 PAGE 4 GE PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.**FUEL SYSTEM - Fuel System (73-00-00) - Introduction of Fuel Filter Differential Pressure Switch Collar**  (3) Consumables: None. B. I n d u s t ry S u p p o rt I n fo r m at i o n None. C. C o n fi g u rat i o n C h a rt

N e w P a rt N u m b e r Q ty/ E n g P a rt N a m e O l d P a rt N u m b e r / I P C L o cat i o n Q ty/ E n g O p C o d e C h g/ S p rt C o d e 3062T85G01 (X) Accessory Section Module (SIN 29900) 3062T85G01 72-00-00-01-140 (X) RM -/-

.4110T53P06 (X) Fuel Filter Assembly (SIN 31300) .4110T53P06 73-00-00-01-440 (X) RM -/-

..TD028VF0H7Y5 (X) Switch, Differential Pressure ..TD028VF0H7Y5 73-00-00-01-485 (X) RM -/C

-- (-) Capscrew, Socket Head ..NAS1352C08LE8 73-00-00-01-480 (2) SU 3/- ..59TC02800K1T (X) Kit, Fuel Filter Differential Pressure Switch Collar -- (X) AD 3/-

...88TC02800000 (1) Collar -- (-) AD 3/- ...NAS1352C08LE12 (2) Capscrew, Socket Head -- (-) AD 3/-

O p e rat i o n C o d e s AD = Add RM = Remains SU = Superseded C h a n g e C o d e s 3 = Not interchangeable S u p p o rt C o d e s C = Old parts will be supplied until redesigned differential pressure switch is available.

August 17, 2011 CT7-8 S/B 73-A0008 PAGE 5 GE PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.**FUEL SYSTEM - Fuel System (73-00-00) - Introduction of Fuel Filter Differential Pressure Switch Collar**  D. P a rt s D i s p o s i t i o n None. E. T o o l i n g - P r i c e a n d Av a i l a b i l i ty None. 3. A C C O M P L I S H M E N T I N S T R U C T I O N S A. I n st a l l at i o n o f C o l l a r N O T E : **.** A collar may be installed on a differential pressure switch that exceeds the crack limits of CT7-8 S/B 73-A0007.

**.** It is not necessary to unseat the differential pressure switch from the fi lter head of the fuel fi lter assembly or disconnect the electrical harness. If the differential pressure switch is removed from the fi lter, the packings must be replaced and a normal leak check must be performed. Refer to GEK 105159, 73-00-00, INSTALLATION 010.

**.** There is normally a small gap between the bottom of the bolt fl anges of the differential pressure switch and the surface of the fi lter head. This is normal.

**.** There will be a small gap between the bottom of the collar bolt fl anges and the top of the differential pressure switch bolt fl anges. This is normal.

**.** Do not attempt to close gaps during torquing of the screws. (1) While holding differential pressure switch (1, fi gure 1) fl ush against the fi lter head of the fuel fi lter assembly, remove two socket head capscrews (4), P/N NAS1352C08LE8. Discard the capscrews. (2) Place collar (2) against the forward face of differential pressure switch (1) and secure collar with two capscrews (3) (P/N NAS1352C08LE12). (3) Alternately tighten the capscrew by hand. Be sure the collar remains evenly seated while tightening. Torque capscrews (3) to 13-15 lb in. (1.5-1.8 N.m). (4) After the collar (2) has been installed on a differential pressure switch (1), cease daily crack inspections required by CT7-8 S/B 73-A0007. B. R e i d e n t i fi c at i o n Not applicable.

August 17, 2011 CT7-8 S/B 73-A0008 PAGE 6 GE PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.**FUEL SYSTEM - Fuel System (73-00-00) - Introduction of Fuel Filter Differential Pressure Switch Collar**  C. P o s t M a i n t e n a n c e T e s t (1) If the differential pressure switch (1) was removed, perform an IDLE leak check. Refer to GEK 105159, 72-00-00, TESTING 004. (2) If the electrical harness was disconnected, check for fault codes at next start. D. S e rv i c e R e co rd E n t ry Record compliance with this Service Bulletin in the appropriate CT7-8 Turboshaft Engine Service Record. Report compliance to your GE Field Service Representative.

August 17, 2011 CT7-8 S/B 73-A0008 PAGE 7 GE PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.**FUEL SYSTEM - Fuel System (73-00-00) - Introduction of Fuel Filter Differential Pressure Switch Collar** 

Differential Pressure Switch P/N TD028V F0H7Y5, Installation of Collar P/N 88TC02800000 Figure 1

August 17, 2011 CT7-8 S/B 73-A0008 PAGE 8 GE PROPRIETARY INFORMATION - Subject to the restrictions on the cover or first page.