Airworthiness Directive · Amendment 39-16783 · General Electric Company (GE) CF6-45 Series and CF6-50 Series Turbofan Engines
General Electric Company (GE) CF6-45 Series and CF6-50 Series Turbofan Engines
Superseded. A later AD replaced this one: AD 2012-02-07. Comply with the one in force.
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, CF6-50E, CF6-50E1, and CF6-50E2 series turbofan engines, including engines marked on the engine data plate as CF6-50C2-F and CF6-50C2-R, with a low-pressure turbine (LPT) rotor stage 3 disk that has a part number (P/N) listed in Table 1 of this AD installed.
| 1473M90P01 | 1473M90P02 | 1473M90P03 | 1473M90P04 |
| 1479M75P01 | 1479M75P02 | 1479M75P03 | 1479M75P04 |
| 1479M75P05 | 1479M75P06 | 1479M75P07 | 1479M75P08 |
| 1479M75P09 | 1479M75P11 | 1479M75P13 | 1479M75P14 |
| 9061M23P06 | 9061M23P07 | 9061M23P08 | 9061M23P09 |
| 9061M23P10 | 9061M23P12 | 9061M23P14 | 9061M23P15 |
| 9061M23P16 | 9224M75P01 |
We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires performing a fluorescent penetrant inspection (FPI) of the low-pressure turbine (LPT) rotor stage 3 disk at every shop visit at which the LPT module is separated from the engine. This AD was prompted by seven reports of uncontained failures of LPT rotor stage 3 disks and eight reports of cracked LPT rotor stage 3 disks found during shop visit inspections. We are issuing this AD to prevent LPT rotor separation, which could result in an uncontained engine failure and damage to the airplane.
You are responsible for having the actions required by this AD performed at each shop visit after the effective date of this AD, at which the LPT module assembly is separated from the engine.
At the next shop visit after the effective date of this AD, clean and fluorescent-penetrant inspect the LPT rotor stage 3 disk forward spacer arm, including the use of a wet-abrasive blast to eliminate residual or background fluorescence before inspecting. You can find guidance on cleaning the disk and performing the FPI in the CF6-50 Engine Manual, GEK 50481 72-57-02.
Thereafter, clean and inspect the LPT rotor stage 3 disk forward spacer arm, as specified in paragraph (f) of this AD, at each engine shop visit that occurs after 1,000 cycles since the last FPI of the LPT rotor stage 3 disk forward spacer arm.
(h) If a crack or a band of fluorescence is present, remove the disk from service.
(i) For the purpose of this AD:
(1) The LPT module assembly is defined as consisting of turbine mid-frame, LPT stage 1 nozzle, LPT stator cases and vanes, LPT rotor, and turbine rear frame.
(2) An engine shop visit is the induction of an engine into the shop for maintenance involving the separation of the turbine mid-frame forward flange from the compressor rear frame aft flange, except that the separation of these engine flanges solely for the purposes of transportation without subsequent engine maintenance does not constitute an engine shop visit.
