Airworthiness Directives; Boeing Model 747 and 767 Series Airplanes Equipped with Rolls-Royce Model RB211-524G/H Engines

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 and 767 series airplanes. This action requires modification of the engine fire detection system. This amendment is prompted by a report of a combustor burn-through event that damaged the engine fire detection system such that no fire warning message was annunciated in the flight deck. The actions specified in this AD are intended to prevent failure of the engine fire detection system to annunciate a fire warning message to the flight crew following a severe engine failure, which could lead to delayed or improper flight crew response to the engine failure.