Airworthiness Directives; Boeing Model 757-200 Series Airplanes Powered by Rolls-Royce RB211-535E4/E4B Engines

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 757-200 series airplanes, that requires repetitive inspections to detect cracking of the honeycomb core of the acoustic panels in the engine inlet, and repair, if necessary. This amendment also requires eventual replacement of the existing engine inlet with a new or serviceable inlet, which, when accomplished, terminates the repetitive inspections. This amendment is prompted by reports of cracking of the honeycomb core of the acoustic panels in the engine inlet, and incidents of pieces of the panels breaking off and being ingested into the engine. The actions specified by this AD are intended to detect and correct cracking of the honeycomb core of the acoustic panels in the engine inlet, which could result in reduced structural integrity of the engine inlet, and consequent engine shutdown or surge; or, in the event of a fan blade failure, separation of the inlet from the engine.