F4Blade

TURBO PRODUCTS

Pond Meadow Road

P. O. Box 457

Ivoryton, CT 06442

INSTALLATION, AND INSPECTION REQUIREMENTS FOR;

PT6A TURBINE BLADES

MANUFACTURED BY TURBO PRODUCTS

P/N T023401, P/N T102401-01, P/N T102401-100, P/N T102401-792

The above listed Turbo Products PT6A turbine blades are replacements for PWC P/N 3023401, 3102401-01, et al. The Federal Aviation Administration (FAA) has granted Production Approval (formerly FAA Parts Manufacturer Approval (PMA)) to Turbo Products because these blades are physically and functionally interchangeable with the PWC turbine blades they replace. Since these Turbo Products turbine blades are physically and functionally interchangeable with the PWC turbine blades they replace; these turbine blades are to be operated, and removed in accordance with existing PWC PT6A maintenance manuals. HOWEVER, since these turbine blades incorporate design improvements which the PWC turbine blades do not offer; different installation, inspection and repair procedures are appropriate. This Installation, and Inspection Requirements document has been prepared to make this information available to users of Turbo Products turbine blades. This document may be shared with any airworthiness regulatory authority approved maintenance facility, if they are working on PT6A engines with Turbo Products turbine blades.

1. Compressor turbine blades must be submitted for overhaul inspection, first at 5000 hours since new and then every 3000 hours thereafter. Such inspection will include non-destructive inspection and stretch measurement in accordance with the Inspection and Overhaul Procedure for Turbo Products PT6A turbine blades.

2. Removal of the compressor turbine blades from the compressor turbine disk.

See PWC PT6A Maintenance Manual for removal / installation instructions. Maintenance Manual locations are listed at the end of this procedure.

3. Installation of the compressor turbine blades into the compressor turbine disk.

See PWC PT6A Maintenance Manual for removal / installation instructions. Maintenance Manual locations are listed at the end of this procedure.

CT Blades, Page , Sept. 25, 2001, Intended for general distribution.

After the compressor turbine blades have been placed in their respective locations in the compressor turbine disk but before the compressor turbine blades are riveted in to the compressor turbine disk, perform the following inspection.

Using fifty eight 0.003 inch feeler gages, check gaps between all platforms simultaneously. All gaps must be at least 0.003 inches. Remove feeler gages. If all gaps are not at least 0.003 inches; corrective action is required.

If one or more of the platform gaps measure less than 0.003 inches; there are several possible causes: (1) P&WC has manufactured some disks with the fir tree slots placed closer to the disk center line; (2) Turbo Products manufactured some compressor turbine blades with Sermaloy J over spray on the platform edges; or, (3) corrosion accumulation on the blade platform edges, especially on aircraft used for crop dusting or amphibious operation on salt water.

If one or more of the platform gaps measure less than 0.003 inches; return the disk and blade assembly to one of the facilities listed immediately below. The blades will be removed from the disk. If there is Sermaloy J over spray, the over spray will be removed. An inspection of the disk and blade assembly will be performed. If after the over spray is removed, one or more of the platform gaps still measure less than 0.003 inches; blades will be reworked (by Turbo Products) or replaced as necessary in order to correct the fit between the blade platforms (this assumes there is no corrosion present). If there is corrosion on the blade platforms or on the airfoils the blades will be evaluated and probably stripped, overhaul inspected and recoated (this assumes the blades are in a condition suitable for overhaul) (see paragraph 5B).

Ship disk and blade assemblies with Turbo Products FAA PMA blades installed and blade to blade platform gaps of less than 0.003 inches to:

(a) Prime Turbines, Barnstable Municipal Airport, 630 Barnstable Road, Hyannis MA 02601 Tel: 508 771 4744, FAX: 508 790 0038. OR,

(b) United Turbine, 8045 N. W. 90th Street, Miami FL 33166, Tel: 305 885 3900, FAX: 305 885 0472. OR,

(c) Turbines Inc., Terre Haute International Airport, 7303 Maynard Wheeler Lane, Terre Haute IN 47803, Tel: 812 877 2587, FAX: 812 877 4704. OR,

After the above inspection requirements have been satisfactorily completed, continue the installation of the compressor turbine blades into the compressor turbine disk in accordance with the P&WC installation instructions.

CT Blades, Page , Sept. 25, 2001, Intended for general distribution.

4. Installation of the compressor turbine disk and blade assembly into the engine:

See PWC PT6A Maintenance Manual for removal / installation instructions. Maintenance Manual locations are listed at the end of this procedure.

5. Maintenance Inspection:

A. Compressor Turbine Blade Tip Clearance.

Note: Turbine blade tip clearance should be measured after installation of the compressor turbine disk and blade assembly, and whenever engine performance is unsatisfactory.

(1) Measure and record turbine blade tip clearance at several circumferential locations. The average tip clearance must be: within 0.010 - 0.017 inches for PT6A-25C, 34, 34AG, 34B, 36, 114, 114A; within 0.013 - 0.018 inches for PT6A-25, 25A; and within 0.013 - 0.016 inches for new segments requiring grinding under maintenance manual conditions for PT6A-6, 6A, 6B, 11, 11AG, 15AG, 20, 20A, 20B, 21, 27, 28, 110, 112.

Note: Clearances should be measured using gage wires or tapered feeler gages. For P/N T102401-01, T102401-100, T102401-792, tip clearance is measured at the rearward portion of the blade tip, where taper is at a minimum. Ensure shroud assembly is centralized.

(2) The tip clearance at any one circumferential location should not exceed 0.019 inches for PT6A-6, 6A, 6B, 20, 20A, 20B engines, or 0.021 inches for PT6A-25C, 34, 34AG, 34B, 36, 114, 114A engines, or 0.022 inches for all other engines or be less than 0.008 inches for any engine. However, if clearance does exceed 0.019, or 0.021, or 0.022 inches respectively at one location only, shroud segments may remain in service provided engine performance continues to be satisfactory.

(3) If the tip clearances are less than 0.008 inches, due to a high spot in a shroud segment, the segment may be ground locally over a length not exceeding one inch on any one segment.

Note: For grinding procedure refer to Maintenance Manual location for shroud segments.

(4) Inspect turbine shroud segments for evidence of metal build-up and cracks. See Maintenance Manual location for shroud segments.

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B. Compressor turbine blades, P/N's T023401, T102401-01, T102401-100, and T102401-792.

(1) If compressor turbine vane ring (or turbine vane PT6A-6, 6A, 6B, 20, 20A, 20B, 6/C20) inspection reveals that vane trailing edge burning has resulted in a loss of airfoil area of 0.125 square inch or more on any one vane, and the burned area can be seen from the leading edge of the vane (ring) when viewed parallel to the engine longitudinal axis, the entire set of CT blades must be scrapped. (Reference Maintenance Manual section for CT blades.)

(2) Inspect blade airfoil surfaces for corrosion and loss of coating using 10X magnification. A loss of coating up to 25% is acceptable. Loss of coating should be repaired, at operators discretion, to prevent accelerated sulfidation attack. Return CT blades for overhaul to the facility listed in this procedure if any of the following conditions exist, unless directed otherwise.

Assess stage of deterioration and accept or reject bladed disk as follows:

Stage 1 sulfidation, as seen by a slight color change of part of the coating area. May be rust colored or dark gray. Coating has begun to deteriorate, but is probably still intact. Blades are acceptable for further service. At the operator's discretion, blades should be refurbished to prevent further coating loss and accelerated sulfidation. At this stage, nearly all blades may be successfully re-coated at overhaul.

Stage 2 sulfidation, as seen by an apparent rise of sulfidated coating over surrounding surface, with small, scattered blisters appearing in the coating. Corrosion of parent material has begun and hot corrosion products are in parent material. Accept or reject disk at the discretion of the operator, based on previous experience. Blades should be submitted for overhaul inspection and re-coating to prevent further coating loss and sulfidation. At this stage, many but not all blades may be successfully re-coated at overhaul. If blades are to remain in service, operator must increase desalination washes and schedule regular borescope inspection of blades every 200 flight hours.

Stage 3 advanced sulfidation corrosion, evidenced by clusters of ruptured blisters exposing bare material. Craters formed, progressively deepen and crater surfaces darken with a glazed appearance. Blades are to be scrapped and replaced with serviceable blades. New or serviceable blades are to be installed in accordance with the overhaul manual. Blades with this type of corrosion can not be re-coated.

CT Blades, Page , Sept. 25, 2001, Intended for general distribution.

Stage 4 deep sulfidation penetration with large ruptured blisters exposing large area of corroded parent material. Blades have experienced structural loss (failure is likely). Immediately remove blades from service.

(3) Blade Shift: Protrusion of blade root beyond disk rim must be equal within 0.016 inches on either side of disk. If limit is exceeded send blades to overhaul facility for full inspection.

(4) Circumferential Movement: Circumferential movement, measured at blade tip, is not to exceed 0.030 inches. If limit is exceeded send blades to overhaul facility for full inspection.

(5) Squealer Tip Rub: Minimum acceptable squealer tip height is 0.008 inches. to continue in service. If limit is exceeded send blades to overhaul facility for full inspection.

(6) Airfoil area high and low pressure side (i.e. not fillet area, not leading and trailing edges): Maximum allowable damage to continue in service is three nicks, dents, or pits not exceeding 0.003 inch depth (PT6A-25C, 34, 34AG, 34B, 36, 114, 114A) or 0.005 inch depth (PT6A-6, 6A, 6B, 11, 11AG, 15AG, 20, 20A, 20B, 6/C20, 21, 25, 25A, 27, 28, 110, 112). If limit is exceeded send blades to overhaul facility for full inspection. Cracks are not acceptable, send blades to overhaul facility for full inspection.

(7) Fillet area, 0.100 inches from blade platform high and low pressure side: Maximum allowable damage to continue in service is one nick, dent, or pit not exceeding 0.005 inches depth. If limit is exceeded send blades to overhaul facility for full inspection. Cracks are not acceptable, send blades to overhaul facility for full inspection.

(8) Leading and trailing edges, 0.100 inches from either edge: Maximum allowable damage to continue in service is one nick, dent, or pit not exceeding 0.020 inches depth. If limit is exceeded send blades to overhaul facility for full inspection. Cracks are not acceptable, send blades to overhaul facility for full inspection.

(9) Leading edge tip: Maximum acceptable erosion is 0.200 inch radius without blending. If limit is exceeded send blades to overhaul facility for full inspection. Cracks are not acceptable, send blades to overhaul facility for full inspection.

(10) If any blade is found cracked, return turbine assembly to overhaul facility for replacement of complete set of blades.

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(11) Cracks may not extend beyond coating depth. If, after stripping coating, the cracks do not extend into the base metal, the blades may be considered serviceable. Other, normal inspection criteria must be applied.

(12) Blades having thinned or feathered leading edges due to erosion are not acceptable.

(13) Using fifty eight 0.003 inch feeler gages, check gaps between all platforms simultaneously. All gaps must be at least 0.003 inches. Remove feeler gages. If all gaps are not at least 0.003 inches; corrective action is required.

If the platform gaps measure at least 0.003 inches in every one of the fifty eight blade platform to platform gaps, make an entry in the engine log book and it will not be necessary to repeat this particular part of the inspection process until the blades are removed from the disk and blades are reinstalled, or unless significant sulfidation is observed on the blade airfoils.

Ship disk and blade assemblies with Turbo Products FAA PMA blades installed and blade to blade platform gaps of less than 0.003 inches to:

(a) Prime Turbines, Barnstable Municipal Airport, 630 Barnstable Road, Hyannis MA 02601 Tel: 508 771 4744, FAX: 508 790 0038. OR,

(b) United Turbine, 8045 N. W. 90th Street, Miami FL 33166, Tel: 305 885 3900, FAX: 305 885 0472. OR,

(c) Turbines Inc., Terre Haute International Airport, 7303 Maynard Wheeler Lane, Terre Haute IN 47803, Tel: 812 877 2587, FAX: 812 877 4704.

CT Blades, Page , Sept. 25, 2001, Intended for general distribution.

C. When blades need overhaul due to time accumulation (i.e. 5,000 hours or 3,000 hours) or blade condition, send blades to one of the following overhaul facilities for complete overhaul inspection and refurbishment (i.e. inspection, repair, and re-coating). Note, have the blades disassembled from the disk and blade assembly prior to shipment for overhaul inspection and refurbishment.

Dean Machine Products Inc.

102 Colonial Road

Manchester, CT 06040

1-800-966-5265 voice

1-860-649-5265 voice

1-860-647-7342 FAX

Connecticut Turbine Technologies

372 Progress Drive

Manchester, CT 06040

1-800-649-1877 voice

1-860-647-1642 FAX

NOTE: Repair orders for CT blades being sent to the above facilities for overhaul must have a signed statement certifying that CT blades have not been subjected to CT vane burn through in excess of the limits described in paragraph 5. B. (1) of this Inspection Requirements procedure.

D. References: This Installation, and Inspection Requirements document is intended to supplement Pratt and Whitney Canada maintenance manuals and manual locations as follows:

PT6A-21, 27, 28 Maintenance Manual, P/N 3013242

Section 72-50-02, pages 201 through 215.

PT6A-6 Series and PT6A-20 Series Maintenance Manual P/N 3015442

Pages 3-3-8G, 3-3-8H, 3-3-8I, 3-3-10, 3-3-18A, 3-3-19, 3-3-22, 3-3-23, and Table 3-3-3.

PT6A-11, 11AG, 15AG, 110, 112 Maintenance Manual, P/N 3030442

Section 72-50-12, pages 201 through 208, including 202A, 202B.

PT6A-34, 34AG, 34B, 36 Maintenance Manual, P/N 3021242

Section 72-50-02, pages 201 through 214.

PT6A-25, 25A Maintenance Manual, P/N 3027542

Section 72-52-02, pages 201 through 209, including 202A, 202B.

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PT6A-25C Maintenance Manual, P/N 3032142

Section 72-52-12, pages 201 through 211, including 202A, 202B, 208A.

PT6A-114, 114A, 116, 135, 135A Maintenance Manual, P/N 3043512

Section 72-50-02, pages 201 through 214.

This Installation, and Inspection Requirements document is Federal Aviation Administration, Designated Engineering Representative (FAA DER) approved.

CT Blades, Page , Sept. 25, 2001, Intended for general distribution.

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