Sb 5003r37 Tbo & Hsi Frequency

BULLETIN INDEX LOCATORTURBOSHAFT ENGINE

OPERATING TIME BETWEEN OVERHAULS AND HOT SECTION INSPECTION FREQUENCY

MODEL APPLICATION

PT6T-3, PT6T-3B, PT6T-3BE, PT6T-3BF, PT6T-3BG, PT6T-3D, PT6T-3DE, PT6T-3DF, PT6T-6,PT6T-6B, ST6T-76

Compliance: Refer to Para. 1.E. in the Service Bulletin

Summary: This service bulletin provides a suggested basic operating time between overhaulsand specifies a suggested initial hot section inspection frequency.

PRATT & WHITNEY CANADA

SERVICE BULLETINP&WC S.B. No. 5003R37

Jan 12/1973 PT6T-72-5003Revision No. 37: Apr 29/2004 Cover Sheet

24-Hour Global Service USA & CANADA........................ 1-800-268-8000 Other .......................................... 1-450-647-8000

HELP DESK International .................... (IAC*)+8000-268-8000 Fax ............................................. 1-450-647-2888

Toll free where available (SIL GEN-027) * International Access Code Web Site .................................. www.pwc.ca

REVISION TRANSMITTAL SHEETTURBOSHAFT ENGINE MODEL PT6T

SUBJECT: Pratt & Whitney Canada Service Bulletin No. PT6T-72-5003, Rev. No. 37, dated Apr29/2004 (P&WC S.B. No. 5003R37) OPERATING TIME BETWEEN OVERHAULS ANDHOT SECTION INSPECTION FREQUENCY

Replace your existing copy of this service bulletin with the attached revised bulletin. Destroy thesuperseded copy.

Please retain this Revision Transmittal Sheet with the revised bulletin.

SUMMARY: This revision is issued to:

v increase the comply period for the AFCU to Sep 1st 2005.

v the TBO information for the CT blades has been transferred from SB 5002 to SB5003.

EFFECT OF REVISION ON PRIOR ACCOMPLISHMENT:

None.

NOTE: A black bar in the left margin indicates a change in that line of text or figure.

REVISION HISTORY:

Original Issue: Jan 12/1973Revision No. 1: Apr 16/1974Revision No. 2: May 21/1974Revision No. 3: Jul 08/1974Revision No. 4: Dec 10/1974Revision No. 5: Feb 07/1975Revision No. 6: Jul 19/1975Revision No. 7: Sep 12/1975Revision No. 8: Jun 30/1976Revision No. 9: Dec 14/1976

Revision No. 10: Nov 04/1977Revision No. 11: Mar 23/1978Revision No. 12: Nov 28/1978Revision No. 13: Mar 13/1979Revision No. 14: Jul 13/1979Revision No. 15: Jan 30/1980Revision No. 16: Oct 06/1980Revision No. 17: Apr 28/1981Revision No. 18: Jul 08/1983Revision No. 19: Oct 14/1983

Revision No. 20: Mar 21/1984Revision No. 21: Jun 20/1984Revision No. 22: Aug 20/1985Revision No. 23: Aug 28/1986Revision No. 24: Dec 04/1986Revision No. 25: Dec 15/1987Revision No. 26: Feb 23/1989Revision No. 27: Aug 02/1989Revision No. 28: Nov 15/1990Revision No. 29: Jan 30/1991

Pratt & Whitney Canada Corp.1000, Marie-VictorinLongueuil, Québec, Canada J4G 1A1Tél. 450-677-9411

29 April 2004

P&WC S.B. No. 5003R37

Revision No. 30: Sep 02/1994Revision No. 31: Nov 01/1995Revision No. 32: Dec 02/1996Revision No. 33: Dec 01/1997Revision No. 34: Aug 18/1999Revision No. 35: Dec 22/2003Revision No. 36: Feb 16/2004Revision No. 37: Apr 29/2004

Pratt & Whitney Canada Corp.

1. Planning Information

A. Effectivity

PT6T-3, PT6T-3B, PT6T-3BE, PT6T-3BF, PT6T-3BG, PT6T-3D, PT6T-3DE, PT6T-3DF,PT6T-6, PT6T-6B Engines

ST6T-76 Engines

B. Concurrent Requirements

None.

C. Reason

To provide a currently recommended basic operating time interval between overhaulsand to specify the conditions for Hot Section Inspection.

D. Description

(1) Time Between Overhaul (TBO) recommendations take into consideration theaverage effect of the many variables affecting overhaul life such as average flightduration, percentage of time at any given power level, climatic conditions andenvironment, maintenance practices, utilization and engine modification standard.

(2) Under extreme conditions of very low utilization coupled with continuous operationin salt water atmosphere or heavy sand and dust environment, periodic inspectionsin accordance with the applicable maintenance instructions may indicatemaintenance action prior to the recommended overhaul life.

E. Compliance

Pratt & Whitney Canada Inc. recommends that Compliance conforms to the requirementsof the Accomplishment Instructions.

F. Approval

Transport Canada has reviewed and approved the technical contents of this ServiceBulletin.

NOTE: The recommendations contained in Subparagraph 3.A. are subject to approvalby local airworthiness authorities.

G. Weight and Balance

None.

H. Electrical Load Data

Not changed.

P&WC No. NA



Jan 12/1973 PT6T-72-5003Revision No. 37: Apr 29/2004 Page 1 of 10© 1973 Pratt & Whitney Canada Corp.

PRINTED IN CANADA

TURBOSHAFT ENGINEOPERATING TIME BETWEEN OVERHAULS AND HOT SECTION INSPECTION FREQUENCY

1. Planning Information (Cont’d)

I. Software Accomplishment Summary

Not applicable.

J. References

P&WC S.B. No. 5002P&WC S.B. No. 5121P&WC S.B. No. 5188

K. Publications Affected

None.

L. Interchangeability and Intermixability of Parts

Not applicable.

2. Material Information

A. Industry Support Information

Not applicable.

B. Material - Cost and Availability

Not applicable.

C. Manpower

Not applicable.

D. Material Necessary for Each Engine

Not applicable.

E. Reidentified Parts

None.

F. Tooling - Price and Availability

Not applicable.

3. Accomplishment Instructions

A. Time Between Overhaul (TBO) Recommendations



Jan 12/1973 PT6T-72-5003Revision No. 37: Apr 29/2004 Page 2 of 10


3. Accomplishment Instructions (Cont’d)

(1) Rotor component life limitations outlined in the latest revision of P&WC S.B.No. 5002 override TBO considerations.

(2) For the basic power section TBO recommendations, refer to Table 1.

(3) For the basic reduction gearbox TBO recommendations, refer to Table 2.

NOTE: Any PT6T reduction gearbox used for rental applications must be subjectedto the basic TBO specified in this service bulletin.

TABLE 1, Power Sections

MODEL BASIC TBO

PT6T-3 4000 hrs.

PT6T-3B/-3BE/-3BF/-3BG 4000 hrs.

PT6T-3D/-3DE/-3DF 4000 hrs.

PT6T-6/-6B 3000 hrs.

ST6T-76 2000 hrs.

TABLE 2, Reduction Gearboxes

ReductionGearbox

Part Number

Basic TBO

Sikorsky S58T Bell 212/412 Agusta/Bell212/412 I & M ST6

P/N 3017680 2500 (Ref. NOTE 1) (Ref. NOTE 2) N/A

P/N 3024780 2500 (Ref. NOTE 1) (Ref. NOTE 2) N/A

P/N 3027680 N/A N/A N/A 2000 hrs.

P/N 3039080 N/A (Ref. NOTE 1) (Ref. NOTE 2) N/A

P/N 3117180-01 N/A (Ref. NOTE 1) (Ref. NOTE 2) N/A

NOTE 1: Reduction gearboxes operating in Bell model 212 and 412 helicopters must refer toBell 212/412 helicopter Maintenance Manual (MM).

NOTE 2: Reduction gearboxes operating in Agusta/Bell model 212 and 412 helicopters mustrefer to Agusta/Bell Airworthiness Limitations Manual.






B. Hot Section Inspection Recommendations

(1) The PT6T-3D power sections with Build Specification (BS) 807 and BS928,PT6T-3DE power sections with BS893 and PT6T-3DF power sections with BS946require hot section inspection at 2500 hour intervals.

(2) All other PT6T and ST6T power sections have no scheduled hot section inspectioninterval and operate on an ‘‘on-condition’’ basis.

C. Compressor turbine blades must be replaced at or before limits shown in Table 3.

NOTE: C.T. Blades are not considered to be engine rotating component.

TABLE 3, Operating time limit for Compressor Turbine Blades

Part No. Model Total of Hours

3031801 PT6T-3 TBO interval (Ref. NOTE 1)

3104001-01 PT6T-3 TBO interval (Ref. NOTE 1)


3119871-0101R3119871-01 PT6T-3D/-3DE/-3DF 8000 Initial (Ref. NOTE 2)

3043951-02 PT6T-3D/-3DE/-3DF 8000 Initial (Ref. NOTE 2)

3115801-0101R3115801-01 PT6T-3D 8000 Initial (Ref. NOTE 2)

3031701 PT6T-3 TBO interval (Ref. NOTE 1)



NOTE: Recommended total hours overhaul period as per local Airworthinessapproval for TBO extension.

D. Accessories Time Between Overhaul

(1) Engine accessories TBO are defined in Tables 4 and 5.






TABLE 4, Power Section Accessories

ACCESSORY TBO REMARKS

Automatic Fuel Control Unit 6000 hours or 6 years,whichever occurs first.

Note: Calendar time is trackedfrom when unit enters into

service and does not includetime in storage.

Operators must comply withcalendar time TBO by

Sep. 01/2005.Mid life inspection criteria per

MM periodic inspectionrequirements, Chapter

72-00-00.Storage requirements/limits

detailed in MM.

Manual Fuel Control Power Section TBO + 500hours

Engine Driven Fuel Pump Power Section TBO + 500hours

Oil to Fuel Heater Power Section TBO + 500hours

Flow Divider Power Section TBO + 500hours

Bleed Valve On Condition Removal thresholddetermined by operator based

on operational experience.On Pre SB5444 bleed valves,

inspect diaphragm at aninterval established by

operator based on operationalexperience

ITT Trim Compensator On Condition Removal thresholddetermined by operator based

on operational experience

Igniter Exciter On Condition Removal thresholddetermined by operator based


Ignition Cable On Condition Removal thresholddetermined by operator based







TABLE 5, Reduction Gearbox Accessories

ACCESSORY TBO REMARKS

Nf Governor Reduction Gearbox TBO +500 hours

TCU / UTL Reduction Gearbox TBO +500 hours

(2) Where accessories are removed for shop repair and subsequent reinstallationoperating time since new or overhaul must be recorded on repair tag.

E. Fleet TBO Escalations

(1) Escalations to TBO may only be granted with the approval of the applicableregulatory agency. Such escalations may be granted following the satisfactory resultsof a sampling program. Sampling programs are controlled by the regulatoryagencies who will establish the required sample size (satisfactory exhibit) inaccordance with their standards and/or requirements.

(a) Power Section:P&WC recommends submitting one satisfactory exhibit for the power section,operated to the next higher level (500 hrs) above the established TBO.

NOTE: Operators having mixed power section models in their fleet may submitone exhibit from any one of the model groups, to extend their fleetTBO to the next level.

(b) Reduction Gearbox:P&WC recommends submitting three satisfactory exhibit for the RGB, operatedto the next higher level (500 hrs) above the established TBO for each of theengine models covered by this service bulletin.

1 Operators desiring TBO escalations are requested to submit a formalrequest in writing together with details of engine serial number, total timesince new, total time since overhaul, aircraft model, of major repairs (ifany), and confirmation of operation to criteria at Para. 3D 2 (4) to:

Pratt & Whitney Canada Inc.1000 Marie Victorin Blvd.Longueuil QuebecCanada J4G 1A1

Attention: Manager Service EngineeringTurboshaft Engines






2 The customer is responsible to submit the documents to local AirworthinessAuthority for approval of the recommended TBO extension.

(2) The basic TBO is recommended by P&WC and is usually adopted by the aircraftmanufacturer as the fleet TBO for the aircraft type utilizing the engine. Escalationsto fleet TBOs are normally recommended by the engine and aircraftmanufacturer.

(3) Fleet TBOs are usually adopted by operators as initial operator TBOs at thecommencement of operations. Escalations to operator TBOs are usually granted onthe basis of substantiation provided by the engine manufacturer and the operator.

(4) TBO escalations are normally granted in increments of 500 hrs. To qualify forescalations, power sections or RGBs must have been operated in the participatingfleet for not less than 90% of the established TBO interval. RGBs must have beenused exclusively in the aircraft model involved.

(5) An engine maintains its TBO extension recommendation as long as it is operatedwithin the limitations of the relevant engine and aircraft operating manuals and ismaintained in accordance with the appropriate P&WC maintenance manual and theterms of this SB.

NOTE: P&WC reserves the right to withdraw a TBO recommendation in instanceswhere engine abuse or non-compliance with this recommendation arereported.

(6) If the engine was put in storage or was unused for an extended period in the timesince its last overhaul (or since new if not previously overhauled), there must bedocumented evidence that the engine has been preserved per the enginemaintenance manual.

(7) Recommendations are not transferable between operators except undercircumstances described in Para. 3.F.

(8) TBO extension recommendations from P&WC may be subject to fees.

NOTE: When shipping an engine to a P&WC Designated O/H Facility (DOF) as asample, operators should state that it is a sample and request a TBOextension evaluation report (Ref. Fig. 1).

(9) Upon time expiry, the operator shall return the engine (Power Section and/orReduction Gearbox) to a P&WC DOF for overhaul, at the same time requesting aTBO evaluation report from the overhaul facility. The overhaul facility will forwardthe TBO evaluation report to the attention of Service Engineering Manager TurboshaftEngines, who will review the TBO evaluation report and issue a letter ofrecommendation to the customer.





Power Section orReduction GearboxSerial Number:

C72341A

TBO Evaluation Sample Request FormFigure 1






F. Transfer of TBO Extension Recommendations:TBO escalation recommendations are valid only as long as the operator, the maintenanceprovider, and the typical mission remain unchanged.

NOTE: For changes limited to the selection by the operator of a new maintenanceprovider, the change will have no effect if the maintenance plan remainsunchanged.

G. Exhibits for TBO Escalation

(1) For TBO escalations, Airworthiness authorities may not accept exhibits which havebeen subjected to component refurbishment occurring prior to reaching TBOunless:

(a) Prime cause of refurbishment was not directly attributed to self-inducedmalfunction or of mechanical integrity, and;

(b) Refurbishment components have satisfactory prior history beyond theestablished TBO level.

H. For engines operated in aircraft engaged in crop dusting and other chemical applications,flying conditions vary to such a degree that a sampling program for each particularapplication is desirable. Operators are requested to contact P&WC Service EngineeringDepartment for specific recommendations.

I. Determination of remaining life for PT6T Reduction Gearboxes

(1) The following procedure must be used:

(a) To establish remaining life to overhaul for non-mixed operations (gearboxoperated on one model aircraft)

Remaining Life = TBO applicable (Table) - Consumed Time

(b) To establish remaining life to overhaul for mixed operation (same gearboxoperated on different model aircraft)

Example:

Assume that a particular gearbox started life in a model ‘‘A’’ helicopter and wassubsequently utilized in a model ‘‘B’’ machine and it is now required todefine the remaining life for a model ‘‘C’’ helicopter.

Percentage of Life Remaining = 1.0 -( Time in Model A HelicopterGearbox TBO 1 in Model A Helicopter) X 100

- ( Time in Model B HelicopterGearbox TBO 1 in Model B Helicopter) X 100

Remaining Life in Hours =Results of last Step

100 X Gearbox TBO for Model CHelicopter






Numerical Example:

Assuming time in model ‘‘A’’ is 1106 hrs. and TBO is 3500 hrs., assuming timein model ‘‘B’’ is 650 hrs. and TBO is 2500 hrs.; it is required to determinethe remaining time in hours for model ‘‘C’’ helicopter if TBO for model ‘‘C’’ is2500 hrs.

Percentage of Life Remaining = [1.0- (11063500) -

6502500)] X 100 = 42.4%

Remaining Life in Hours =42.4100 X 2500 = 1060

4. Appendix

Not applicable.





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Sb 5003r37 Tbo & Hsi Frequency