AD 2024-05-51 Airworthiness Directives; General Electric Company Engines, and Various Restricted Category Rotorcraft

Models named: CT7-2E1, CT7-2F1, CT7-8A, CT7-8E, CT7-8F5, T700-GE-700, -701A, -701C, -701D/CC, -701D. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to the following products: (1) General Electric Company (GE) Model CT7-2E1, CT7-2F1, CT7-8A, CT7-8E, CT7-8F5 engines, with any power turbine (PT) drive shaft assembly part number 5123T91G01, 5123T91G02, and 5128T51G01 installed, and the following conditions: (i) A PT drive shaft assembly with less than 100 hours-time since new (TSN) or 100 hours-time since replacement (TSR) of the torque reference tube, as applicable, as of the effective date of this AD; and (ii) An engine serial number, PT module serial number, or PT shaft assembly serial number listed in GE Alert Service Bulletin (ASB) CT7-2E1 S/B 72-A0034, dated February 26, 2024 (CT7-2E1 S/B 72-A0034); or GE ASB CT7-8 S/B 72-A0118, Revision 01, dated February 26, 2024 (CT7-8 S/B 72-A0118, Revision 01). (2) Restricted category helicopters specified in paragraphs (c)(2)(i) through (ix) of this AD, with GE Model T700-GE-700, -701A, -701C, -701D/CC, -701D, -401, -401C, CT7-2D or CT7-2D1 engines installed, with a PT drive shaft assembly that was installed in the engine after January 1, 2020 and has less than 100 hours-TSN or 100 hours-TSR, as applicable. PT drive shaft assemblies manufactured or repaired after January 1, 2024 are not affected by this AD. (i) Model EH-60A helicopters; current type certificate holders include, but are not limited to, Delta Enterprise; Heliqwest International Inc.; Pickering Aviation, Inc.; and Sixtyhawk TC, LLC. (ii) Model HH-60L helicopters; current type certificate holders include, but are not limited to, Capitol Helicopters Inc.; Central Copters Inc.; and Sixtyhawk TC, LLC. (iii) Model S-70 helicopters; current type certificate holders include, but are not limited to, Sikorsky Aircraft Corporation. (iv) Model S-70A helicopters; current type certificate holders include, but are not limited to, Sikorsky Aircraft Corporation. (v) Model S-70C helicopters; current type certificate holders include, but are not limited to, Sikorsky Aircraft Corporation. (vi) Model S-70C(M) helicopters; current type certificate holders include, but are not limited to, Sikorsky Aircraft Corporation. (vii) Model S-70C(M1) helicopters; current type certificate holders include, but are not limited to, Sikorsky Aircraft Corporation. (viii) Model S-70M helicopters; current type certificate holders include, but are not limited to, Sikorsky Aircraft Corporation. (ix) Model UH-60A helicopters; current type certificate holders include, but are not limited to, ACE Aeronautics LLC; Billings Flying Service, Inc; Blackhawk Mission Equipment; Capitol Helicopters Inc.; Carson Helicopters; Delta Enterprise; Heliqwest International Inc.; High Performance Helicopters Corp.; Northwest Rotorcraft, LLC; Pickering Aviation, Inc.; PJ Helicopters Inc; Reeder Flying Service Inc.; Sixtyhawk TC, LLC; Skydance Blackhawk Operations LLC; Timberline Helicopters, Inc.; and Unical Air Inc.

Comply with this AD within the compliance times specified, unless already done.

(1) For GE Model CT7-2E1, CT7-2F1, CT7-8A, CT7-8E, CT7-8F5 engines: Before further flight, do a phase array ultrasonic inspection of the torque reference tube magnetic insert braze joint of the power turbine drive shaft assembly for inadequate braze coverage in accordance with the Accomplishment Instructions, paragraph 3.A.(2) of CT7-2E1 S/B 72-A0034, or CT7-8 S/B 72-A0118, Revision 01, as applicable. (2) For engines installed on the restricted category aircraft specified in paragraphs (c)(2)(i) through (ix) of this AD: Before further flight, do a phase array ultrasonic inspection of the torque reference tube magnetic insert braze joint of the power turbine drive shaft assembly for inadequate braze coverage using a method approved by the Manager, AIR-520 Continued Operational Safety Branch, FAA. (3) If during any inspection required by paragraphs (g)(1) or (2) of this AD, any braze coverage of the torque reference tube magnetic insert braze joint is found to be less than 42 percent, before further flight, repair or replace the power turbine drive shaft assembly.

This AD was prompted by at least four reports of failures of the torque reference tube magnetic insert braze joint of the power turbine drive shaft assembly within the last several months. The FAA is issuing this AD to prevent failure of the power turbine drive shaft reference torque tube magnetic insert braze joint. The unsafe condition, if not addressed, could result in improper torque and engine speed indications, which in combination with specific phases of flight, could create an unacceptably high flight crew workload in maintaining control of the aircraft, and result in consequent loss of control of the aircraft.

None.