Airworthiness Directive · Amendment 39-22974 · Engine
General Electric Company Engines
This AD applies to General Electric Company (GE) Model CT7-5A2, CT7-5A3, CT7-7A, CT7-7A1, CT7-9B, CT7-9B1, CT7-9B2, CT7-9C, CT7-9C3, CT7-9D, and CT7-9D2 engines with an installed stage 1 turbine forward cooling plate having part number (P/N) 6064T08P01; or with an installed stage 2 turbine aft cooling plate having P/N 6064T07P05 or P/N 6068T36P01.
The FAA is adopting a new airworthiness directive (AD) for certain General Electric Company (GE) Model CT7-5A2, CT7-5A3, CT7-7A, CT7-7A1, CT7-9B, CT7-9B1, CT7-9B2, CT7-9C, CT7-9C3, CT7-9D, and CT7-9D2 engines. This AD was prompted by the manufacturer's determination that certain GE Model CT7 fleets have affected cooling plates installed that do not meet lifing guidelines. This AD requires replacement of the stage 1 turbine forward cooling plate and the stage 2 turbine aft cooling plate. The FAA is issuing this AD to address the unsafe condition on these products.
Within the compliance times specified in paragraphs (g)(1) through (3) of this AD, replace the affected stage 1 turbine forward cooling plate or stage 2 turbine aft cooling plate, as applicable, with a replacement P/N eligible for installation, in accordance with table 1 to the introductory text of paragraph (g) of this AD:
| Engine group | Part name | Affected P/N | Replacement P/N |
|---|---|---|---|
| 1 | Stage 1 turbine forward cooling plate | 6064T08P01 | 6064T08P04. |
| 1 | Stage 2 turbine aft cooling plate | 6064T07P05 | 6064T07P07. |
| 1 | Stage 2 turbine aft cooling plate | 6068T36P01 | 6068T36P04. |
| 2 | Stage 1 turbine forward cooling plate | 6064T08P01 | 6064T08P03 or 6064T08P04. |
| 2 | Stage 2 turbine aft cooling plate | 6064T07P05 | 6064T07P07. |
| 2 | Stage 2 turbine aft cooling plate | 6068T36P01 | 6068T36P04. |
(1) For Group 1 engines with an affected part installed, replace the affected part at the next exposure of the gas generator stator assembly that occurs after the effective date of this AD.
(2) For Group 2 engines with an affected part installed having 7,000 part cycles since new (PCSN) or less as of the effective date of this AD, replace the affected part at the next exposure of the gas generator stator assembly or within 2,000 flight cycles (FCs) but before reaching 7,500 PCSN, whichever occurs first after the effective date of this AD.
(3) For Group 2 engines with an affected part installed having more than 7,000 PCSN as of the effective date of this AD, replace the affected part at the next exposure of the gas generator stator assembly or within 500 FCs, whichever occurs first after the effective date of this AD.
For the purpose of this AD:
(1) “Group 1 engines” are GE Model CT7-5A2, CT7-5A3, CT7-9B, CT7-9B1, CT7-9B2, CT7-9D, and CT7-9D2 engines.
(2) “Group 2 engines” are GE Model CT7-7A, CT7-7A1, CT7-9C, and CT7-9C3 engines.
(3) “Exposure of the gas generator stator assembly” is when the gas generator rotor and stator assembly are separated from the combustor module.
