AD 2021-12-01 Lowers The Initial Inspection Threshold And Requires Repetitive Ultrasonic Inspections

The FAA is superseding Airworthiness Directive (AD) 2019-25-13, which applied to all Engine Alliance (EA) GP7270 and GP7277 model turbofan engines with a certain low-pressure compressor (LPC) 1st-stage fan blade installed.

AD 2019-25-13 required an ultrasonic inspection of the affected LPC 1st-stage fan blades and replacement of any affected LPC 1st-stage fan blade that fails the inspection. This AD lowers the initial inspection threshold and requires repetitive ultrasonic inspections on affected LPC 1st-stage fan blades. This AD was prompted by a report of an in-flight shutdown (IFSD) of an engine due to the fracture of multiple LPC 1st-stage fan blades. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective June 28, 2021.

Supplementary Information: The FAA issued AD 2019-25-13, Amendment 39-21011 (84 FR 71770, December 30, 2019), (AD 2019-25-13), for all EA GP7270 and GP7277 model turbofan engines with a certain LPC 1ststage fan blade installed. AD 2019-25-13 required an ultrasonic inspection of the affected LPC 1ststage fan blades and replacement of any affected fan blades that fail the inspection. AD 2019-25-13 resulted from a report of an IFSD of an engine due to the fracture of multiple LPC 1st-stage fan blades. After an analysis of these fractures, the manufacturer determined the fan blades experienced cracks that originated on the internal surface of the convex airfoil and propagated to the point of failure. The cracks originated in a microtexture area that can result in a low-cycle fatigue debit that may allow a crack to initiate and propagate to failure. The FAA issued AD 2019-25-13 to prevent failure of the fan blade.

FMI: www.regulations.gov