May 12,2016 

Federal Aviation Administration 

New England Region 

Engine and Propeller Directorate 

Engine Certification Office (ANE-142) 

1200 District A venue 

Burlington, MA 01803 

Attention: ANE-142 (Chris Spinney) 

0~!!!~~, 400 Main Street, East Hartford, Connecticut 06108 

Subject: AMOC to AD 2013-02-02: Removal ofCFM56-3 Series Engine HPT Disks 

Manufactured by Pratt & Whitney (STC SE00034EN) 

Reference: 1) P& W Special Instruction 6F-12, "Field Management Plan for OMS HPT 

Disks with Possible Low Creep Properties", dated December 21, 2012 

Mr. Spinney; 

2) DRAFT: P&W Special Instruction 6F-12 Revision A, "Field Management 

Plan for OMS HPT Disks with Possible Low Creep Properties", dated May 17, 

2016. 

Attached please find a copy of AD 2013-02-02 and the referenced P&W Special Instructions. The 

subject Airworthiness Directive requires removal from service of five high pressure turbine (HPT) disks 

manufactured by Pratt & Whitney at reduced life limits due to a forging process error. 

These disks are included in P&W Supplemental Type Certificate SN00034EN for incorporation in CFM 

International CFM56-3 series engines. 

In paragraph (c) of the AD, and in the P&W Special Instruction (reference 1), the five serial numbers of 

the disk are in error. Two letters were transposed. The Table below shows the serial numbers as written 

in the AD and Special Instruction, and the correct serial numbers. 

Incorrect Serial Numbers 

As Shown in AD and Sl Correct Serial Numbers 

GLKBAA9307 GKLBAA9307 

GLKBAA9335 GKLBAA9335 

GLKBAA9404 GKLBAA9404 

GLKBAA9407 GKLBAA9407 

GLKBAA9409 GKLBAA9409 

WARNING - This document contains technical data the export of which Is or may be restricted by the Export Administration Act and the Export Administration 

Regulations (EAR), 15 C.F.R. parts 730-774. Diversion contrary to U.S. Iaw is prohibited. The export. re-export, transfer or re-transfer of this technical data to 

any ather company, entity, person, or destination, or for any use or purpose other than that for which the technical data was origlndy provided by P&W, is 

prohibited without prior written approval from P&W and authorization under applicable export control laws. U.S. Export Controlled (ECCN 9E991) 

Warning: This doe001ent Is the property of United Technologies Corporation (UTC). You may not possess, use, copy or disclose this document or any Information 

In it, for any purpose Without UTC's express written pennlsslon. Neither receipt nor possession of this document alone, from any source. constitutes such 

permission. Possession, use. copying or disclosure by anyone without UTC's express written pennission Is not authorized and may result in criminal and/or civil 

liability. 
As a result of this error, Pratt and Whitney requests an Alternate Means of Compliance to allow the use 

of revised Special Instruction, 6F -12 Revision A, dated May 17, 2016 which has the correct serial 

numbers. No other change was made to the Special Instruction. 

Please contact this office if there are any questions. 

Sincerely, 

~lr??r~ Certification & Airworthiness 

FAA-Designated Engineering Representative 

Attachments 

cc: Glorianne Niebuhr 

Subject to the export control and proprietary restrictions on the first page of this doc:umenl 
SPECIAL INSTRUCTION NO. 6F-12 REVISION A May 17, 2016 

Field Management Plan for GMS HPT Disks with Possible Low Creep Properties 

APPLICATION: 

This Special Instruction (SI) is for GMS High Pressure Turbine (HPT) disks P/N 880026 installed in 

CFM56TM engine serial numbers E721528-02, E724785-02, E721613-02, E721878-02 and 

E721121-02. 

THE REASON FOR SPECIAL INSTRUCTION: SUMMARY: DUE TO A 

MANUFACTURING MATERIAL PROCESSING ISSUE. FIVE P/N 880026 HPT ROTOR 

DISKS SHALL HAVE THEIR LCF MAXIMUM LIFE LIMITS REDUCED. 

Problem: Five P/N 880026 HPT disks currently in service may not meet the published LCF 

Maximum Life Limit as indicated in the Time Limits section of the STC engine manual (Ref. 1). 

Cause: Due to a manufacturing material processing issue, the material properties of the 

disks may not be as expected and creep properties in the disk rim could be less than the design 

intent. A possible change in blade slot geometry may increase stress on the HPT blades at the 

disk/blade interface and cause the blades to have reduced LCF life. 

Solution: The LCF Maximum Life Limit for the five HPT disks shall be reduced. To determine 

the impact on the HPT blades, the HPT disk's blade attachment area shall be dimensionally 

inspected to determine if there has been a change in geometry due to creep. See Accomplishment 

Instructions for specific field management information. 

APPROVAL: 

The Field Management Plan as described in the Accomplishment Instructions of this Sl is 

FAA approved. 

WARNING -- This document contains technical data the export of which is or may be restricted by the Export 

Administration Act and the Export Administration Regulations (EAR), 15 C.F.R. parts 730-774. Diversion 

contrary to U.S. law is prohibited. The export, re-export, transfer or re-transfer of this technical data to any 

other company, entity, person, or destination, or for any use or purpose other than that for which the technical 

data was originally provided by P&W, is prohibited without prior written approval from P&W and 

authorization under applicable export control laws. 

Distribution Code 

Special Distribution 

Internal Reference No. 

JRM 121C008A 

Page 1 of 4 

This export marking supersedes all existing export notes in this document. 

This document has not been Export classified. Do not Export. 
SPECIAL INSTRUCTION NO. 6F-12A 

DESCRIPTION: 

For five HPT Disk P/N 880026, serial numbers GKLBAA9407, GKLBAA9409, GKLBAA9404, 

GKLBAA9307 and GKLBAA9335, remove from service and return to Pratt & Whitney for 

dimensional inspection as indicated in the Accomplishment Instructions. 

REFERENCES: 

(1) GMS CFM56-3TM STC Engine Manual P/N PW9325M80-1, 05-00-00 "EngineAirworthiness Limitations - Time Limits" 

(2) P&W Supplemental Type Certificate No. SE00034EN 

NECESSARY TOOLS: 

No more Support Equipment is necessary. 

ADDED DATA: 

A. Mixed Thrust Management: When determining total cycles remaining on each disk that is 

used in multiple model or thrust installations, it is permissible to use the following formula: 

r PTC (Type .U. ) J 1- PTC (Type B) 

8000 -

PTC (Type C) } 

x LLC (for Type) = LRC (for Type) l 8000 4000 

Where: PTC =Part Total Cycles Accrued for each Type 

LLC =New Maximum Life Limit Cycles 

LLC (Type A)= 8000 

LLC (Type B)= 8000 

LLC (Type C) = 4000 

Type A= CFM56-3B-1 or CFM56-3B-2 or CFM56-3C-l operating to 20.1K lbs MTO 

Type B = CFM56-3B-2 or CFM56-3C-1 operating to 22.1K lbs MTO 

Type C = CFM56-3C-l operating to 23.5 K MTO 

LRC= Life Remaining Cycles 

Page 2 of 4 

This export marking supersedes all existing export notes in this document. 

This document has not been Export classified. Do not Export. 
SPECIAL INSTRUCTION NO. 6F-12A 

ACCOMPLISHMENT INSTRUCTIONS: 

1. HPT Disk P/N 880026, S/Ns GKLBAA9407, GKLBAA9409, GKLBAA9404, 

GKLBAA9307 and GKLBAA9335 installed in engines indicated in Table 1 should be 

removed from service and deemed unserviceable the next time the parts are available 

at the piece part level, or at a time not to exceed the New Maximum Life Limit indicated 

in Table 2 below, whichever occurs first. 

Table 1 

Engine Serial Number HPT Disk P/N 800026 

Serial Number 

E721528-02 GKLBAA9407 

E724785-02 GKLBAA9409 

E721613-02 GKLBAA9404 

E721878-02 GKLBAA9307 

E721121-02 GKLBAA9335 

Table 2 

Model and Thrust Rating Maximum Life Limit New Maximum 

per Ref. 1 Life Limit 

CFM56-3B-1, CFM56-3B-2 or CFM56- 20,000 cycles 8000 cycles 

3C-1 operating to 20.1 K lbs MTO 

CFM56-3B-2 or CFM56-3C-1 18,500 cycles 8000 cycles 

operating to 22.1 K lbs MTO 

CFM56-3C-1 operating to 23.5K lbs MTO 16,600 cycles 4000 cycles 

Note: While the HPT disks of Table 1 are in service, it is permissible to use Mixed Thrust 

Management to determine remaining cycles using the formula in Added Data. 

2. Return disks to Pratt & Whitney. Contact Manager, Customer Technical Service, for 

instructions for return of parts. 

Page 3 of 4 

This export marking supersedes all existing export notes in this document. 

This document has not been Export classified. Do not Export. 
SPECIAL INSTRUCTION NO. 6F-12A 

3. The HPT blades removed from each disk shall not be eligible for overhaul processing 

until it is confirmed that the HPT disk meets blade slot dimensional requirements. 

a. When removed from the engine, the HPT blade serial numbers and the 

associated HPT Disk serial number should be documented and the blades held 

pending dimensional inspection of the HPT disk. 

b. The HPT disk should be returned to Pratt & Whitney for dimensional inspection 

of the blade slots to confirm that creep has not occurred . Acceptable blade slot 

geometry is all blade slots conforming to blueprint dimensional requirements, 

except normal wear from blade contact is permitted. 

c. When it is confirmed that HPT disk blade slot geometry is dimensionally 

acceptable, held HPT blades may be released for overhaul processing. If it is 

determined that blade slot geometry is not acceptable, the HPT turbine blades 

shall be deemed unserviceable and not eligible for overhaul processing and 

scrapped. 

MATERIAL INFORMATION: 

A. No new material is being provided by this Special Instruction 

B. See Table 1 for affected engines and parts. 

Page 4 of 4 

This export marking supersedes all existing export notes in this document. 

This document has not been Export classified. Do not Export.