AIRWORTHINESS DIRECTIVE
CAA-AD-4-075/98
Date of issue: November 09, 1998
ENGINE - FAN DISK - INSPECTION
Applicability: All CFM 56-3 engines.
Effective date: December 3, 1998
Compliance: Required as indicated in DGAC AD No. 97-298(B) R2.
Remarks: Where applicable, the requirements of this AD must be integrated into the Aircraft's Logbook(s). Address inquiries concerning this AD to: Civil Aviati
on Authority, Airworthiness Division, Ruzyně Airport, 160 08 Prague 6, Czech Republic, tel.: 420 2 324086, fax: 420 2 364112.Ing. Pavel MATOUŠEK
Director of Airworthiness Division, CAA CZ
GSAC
AIRWORTHINESS DIRECTIVE
released by DIRECTION GENERALE DE L'AVIATION CIVILE
Inspection and/or modifications described below are mandatory. No person may operate a product to which this
Airworthiness Directive applies except in accordance with the requirements of this Airworthiness Directive.
Translation of `Consigne de Navigabilité' ref. : 97-298(B) R2
In case of any difficulty, reference should be made to the French original issue.
CFM INTERNATIONAL
CFM 56-3 engines
Fan disk inspection
Applicability :
All CFM56-3 engines.
Background :
Two in service events occured on CFM56-3 fan modules in 1996 : one blade failure at the root and one fan disk found cracked in two doventails in shop.
Investigations revealed that wear on fan disk doventail pressure faces is the main contributor to these two events.
In order to reduce the risk to have further cracked fan disks in the fleet, the following conditions are made mandatory.
Requirements and Compliance :
As indicated below.
1/ Lubrification Practice
Use of ZIP D5460 NS and ZIP D5460 products to lubricate fan blades is no more allowed.
2/On wing wear inspection following SB 72-854 R1 dated August 07, 1998 or later revision
On CFM56-3/-3B/-3C engines equipped with fan disk which meet the following criteria on effective date of this AD a on wing wear inspection must be performed following the CFMI Service Bulletin 72-854 R1 dated August 07, 1998 or later revision.
- Parts affected by this AD are :
a)Lubricated fan disks with ZIP D5460 or ZIP D5460 NS during more than one year when they reach or already have above 8000 cycles / 14000 hours since new or since rebroach (whichever occur first).
b)Relubricated fan disks with all current recommended lubricants when they reach or already have above 20000 cycles / 35000 hours since new or since rebroach (whichever occur first).
3/ Inspection is not required per this AD
a)If the fan disk has been equipped before 3000 cycles / 5250 hours since new or since rebroach with the following recommended configurations and relubricated with all current recommended lubricants :
25o fan blades with dampers or 37o fan blades for fan disk operated at 20.000 Ibs (8896 daN) thrust rating or less.
37o fan blades with dampers for fan disk operated at any thrust rating.
b)If the fan disk has been inspected at shop level per Engine Shop Manual limits (0.004 inch) 0.10 mm max wear limits in depth and since this inspection equipped with the same following recommended configurations and relubricated with all current recommended lubricants
25o fan blades with dampers or 37 o fan blades for fan disk operated at 20.000 Ibs (8896 daN) thrust rating or less.
37o fan blades with dampers for fan disk operated at any thrust rating.
Ref. : SB CFMI 72-854 R1 dated August 07,1998 or later revision
This Revision 2 replaces AD 97-298(B)R1 dated November 19,1997.
EFFECTIVE DATES :
Original AD : OCTOBER 18,1997
Revision 1 : NOVEMBER 29,1997
Revision 2 : SEPTEMBER 19,1998