COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 747 Series Aeroplanes AD/B747/191 Engine Fire Detection 12/98 Applicability: Model 747 series aeroplanes fitted with Rolls-Royce RB211-524G/H engines. Requirement: Modify the engine fire detection system in accordance with Boeing Alert Service Bulletin 747-26A2250 dated 26 June 1997. Note: FAA AD 98-17-13 Amdt 39-10715 and Rolls-Royce PLC Service Bulletin RB.211-26-C101 refer. Compliance: At the next engine shop visit of the engine but no later than 5 November 2003. This Airworthiness Directive becomes effective on 5 November 1998. Background: The FAA has received a report advising of a combuster burn-through event that damaged the engine fire detection system such that no fire warning was annunciated on the flight deck. This directive implements a modification which is intended to prevent failure of the engine fire detector system to annunciate a fire warning message to flight crew following a severe engine failure. Failure to annunciate a fire warning could lead to delayed or improper flight crew response to the engine failure.