FAA issues Airworthiness Directive: AD 2021-08-01 on Rolls-Royce RB211 Trent 768-60 , RB211 Trent 772-60, and RB211 Trent 772B-60 model turbofan engines installed with certain Low pressure compressor Fan blades and Disks.
Prompted by EASA AD 2020-0253, dated November 12, 2020 from an in-service experience , that highlights the Trent 700 engine LP compressor blades' susceptibility to cracking owing to maintenance actions that caused damage.
This condition, if not detected and corrected, could lead to blade or disc failure and consequent engine in-flight shut-down, possibly resulting in reduced control of the aeroplane.
Both the ADs (EASA and FAA) require repetitive on-wing ultrasonic (US) inspections of the blade roots of the affected blades, subsequent relubrication of the affected blades and discs and, depending on findings, accomplishment of applicable corrective action(s).
AD also requires inshop restoration of the affected blades and discs to a serviceable condition, which constitutes terminating action for the repetitive US inspections and re-lubrications as required by this AD.
For Details on Action, Pls refer : EASA AD 2020-0253, FAA AD 2021-08-01
FAA AD 2021-08-01 to addresses concerns of Trent 700 engine LP compressor blade and disk cracking.
To address this potential unsafe condition, Rolls-Royce issued the inspection NMSB to provide inspection instructions. Rolls-Royce also issued the restoration NMSB to provide in-shop restoration instructions.
The inspection NMSB : RB.211-72-AK492 .
The restoration NMSB : RB.211-72-AK522.
The FAA airworthiness directive (AD) becomes effective on April 30 , 2021.
Source - FAA
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