Airworthiness Directive · Amendment 39-19531 · Turbine engine compressor section
CFM International S.A. Turbofan Engines
This AD applies to CFM International S.A.(CFM) CFM56-7B20, CFM56-7B22, CFM56-7B22/B1, CFM56-7B24, CFM56-7B24/B1, CFM56-7B26, CFM56-7B26/B2, CFM56-7B27, CFM56-7B27A, CFM56-7B26/B1, CFM56-7B27/B1, CFM56-7B27/B3, CFM56-7B20/2, CFM56-7B22/2, CFM56-7B24/2, CFM56-7B26/2, CFM56-7B27/2, CFM56-7B20/3, CFM56-7B22/3, CFM56-7B22/3B1, CFM56-7B24/3, CFM56-7B24/3B1, CFM56-7B26/3, CFM56-7B26/3B1, CFM56-7B26/3B2, CFM56-7B27/3, CFM56-7B27/3B1, CFM56-7B27/3B3, CFM56-7B27A/3, CFM56-7B26/3F, CFM56-7B26/3B2F, CFM56-7B27/3F, CFM56-7B27/3B1F, CFM56-7B20E, CFM56-7B22E, CFM56-7B22E/B1, CFM56-7B24E, CFM56-7B24E/B1, CFM56-7B26E, CFM56-7B26E/B1, CFM56-7B26E/B2, CFM56-7B27AE, CFM56-7B27E, CFM56-7B27E/B1, CFM56-7B27E/B3, CFM56-7B26E/F, CFM56-7B26E/B2F, CFM56-7B27E/F, and CFM56-7B27E/B1F turbofan engine models.
We are superseding Airworthiness Directive (AD) 2018-18-01 for all CFM International S.A. (CFM) Model CFM56-7B turbofan engines. AD 2018-18-01 required initial and repetitive inspections of certain fan blades and, if they fail the inspection, their replacement with parts eligible for installation. This AD requires the same initial and repetitive inspections but revises the compliance time for the initial inspections and revises the installation prohibition based on the updated compliance time. This AD was prompted by further analysis by the manufacturer that indicated a need to reduce the initial fan blade inspection interval based on an ongoing root cause investigation of an April 2018 engine failure. We are issuing this AD to address the unsafe condition on these products.
(1) Perform an ultrasonic inspection (USI) or eddy current inspection (ECI) of the concave and convex sides of the fan blade dovetail as follows:
(i) For a fan blade with less than or equal to 16,000 cycles since new (CSN), inspect prior to accumulating 17,000 CSN.
(ii) For a fan blade with more than 16,000 and less than 20,000 CSN, inspect within 1,000 cycles but no later than 20,000 CSN.
(iii) For a fan blade with 20,000 or more CSN, inspect before further flight.
(iv) Thereafter, repeat this inspection no later than 1,600 cycles since the last inspection, or within 450 cycles after October 16, 2018, the effective date of AD 2018-18-01, whichever occurs later.
(v) Use the Accomplishment Instructions, paragraphs 3.A.(3)(a) through (i), of CFM International Service Bulletin (SB) CFM56-7B S/B 72-1033, Revision 3, dated November 6, 2018, to perform a USI or use the instructions in subtask 72-21-01-220-091, of task 72-21-01-200-001, from CFM CFM56-7B Engine Shop Manual, Revision 57, dated January 15, 2018, to perform an ECI.
(2) If any unserviceable indication, as specified in the applicable service information in paragraph (g)(1)(v) of this AD, is found during the inspections required by paragraph (g) of this AD, replace the fan blade before further flight with a part eligible for installation.
Do not install any replacement fan blade unless it meets one of the following criteria:
(1) The replacement fan blade has fewer than 17,000 CSN, or;
(2) The replacement fan blade has been inspected, per paragraph (g)(1) of this AD, within the last 1,600 cycles before installation.
For the purpose of this AD, a “replacement fan blade” is a fan blade that is being installed into an engine from which it was not previously removed. Removing and reinstalling a fan blade for the purpose of relubrication is not subject to the Installation Prohibition of this AD.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
