2010-06-15: Low-pressure turbine (LPT) stage 3 disks

2010-06-15 General Electric Company: Amendment 39-16240. Docket No. FAA-2010-0068; Directorate Identifier 2010-NE-05-AD. Effective Date (a) This airworthiness directive (AD) becomes effective April 1, 2010. Affected ADs (b) None. Applicability (c) This AD applies to General Electric Company (GE) CF6-45A, CF6-45A2, CF6-50A, CF6-50C, CF6-50CA, CF6-50C1, CF6-50C2, CF6-50C2B, CF6-50C2D, CF6-50C2F, CF6-50C2R, CF6-50E, CF6-50E1, and CF6-50E2, series turbofan engines, with any of the following low-pressure turbine (LPT) stage 3 disks installed: 9061M23P06 9061M23P07 9061M23P08 9061M23P09 9224M75P01 9061M23P10 1473M90P01 1473M90P02 1473M90P03 1473M90P04 9061M23P12 9061M23P14 9061M23P15 9061M23P16 1479M75P01 1479M75P02 1479M75P03 1479M75P04 1479M75P05 1479M75P06 1479M75P07 1479M75P08 1479M75P09 1479M75P11 1479M75P13 1479M75P14 N/A N/A N/A N/A These engines are installed on, but not limited to,Airbus A300 series, Boeing 747 series, McDonnell Douglas DC-10 series, and DC- 10-30F (KDC-10) airplanes. Unsafe Condition (d) This AD results from three reports of uncontained failures of LPT stage 3 disks and eight reports of cracked LPT stage 3 disks found during shop visit inspections. We are issuing this AD to prevent critical life-limited rotating engine part failure, which could result in an uncontained engine failure and damage to the airplane. Compliance (e) You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done. Borescope Inspection of High-Pressure Turbine (HPT) Stage 1 and Stage 2 Rotor Blades (f) Within 50 cycles-in-service (CIS) after the effective date of this AD, borescope-inspect the HPT stage 1 and stage 2 rotor blades for wear and damage, including excessive airfoil material loss. (g) Thereafter, within every 175 CIS, repetitively borescope-inspect the HPT stage 1 and stage 2 rotor blades for wear and damage, including excessive airfoil material loss. Actions Required Whenever the HPT Rotor Blade Cumulative Airfoil Material Loss is 50% of a Blade or More (h) Whenever the HPT rotor blade cumulative airfoil material loss is 50% of a blade or more, then before further flight, fluorescent penetrant inspect the inner diameter surface forward cone body (forward spacer arm) of the LPT stage 3 disk. (i) If the LPT stage 3 disk is cracked or if a circumferential band of fluorescence appears, permanently remove the disk from service. Alternative Methods of Compliance (j) The Manager, Engine Certification Office, has the authority to approve alternative methods of compliance for this AD if requested using the procedures found in 14 CFR 39.19. Related Information (k) Contact Christopher J. Richards, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: christopher.j.richards@faa.gov; telephone (781) 238-7133; fax (781) 238-7199, for more information about this AD. Material Incorporated by Reference (l) None.