COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES Boeing 747 Series Aeroplanes AD/B747/190 Amdt 1 Instrument Landing System Receivers 12/99 DM Applicability: Model 747 series aeroplanes equipped with AlliedSignal RIA-35B Instrument Landing System (ILS) receivers Part Number (P/N) 066-50006-0101. Requirement: 1. Either: 1. Perform a visual inspection of the 64 flight legs of the internal fault memory of all AlliedSignal RIA-35B ILS receivers P/N 066-50006-0101, for fault codes "N1" (glide slope antialias fault) or "Nm" (localizer antialias fault). Or b. (i) Install a placard on the forward instrument panel of the cockpit in clear view of the pilots which states: "Category II and III operations are prohibited.", and (ii) Revise Limitations Section of the AFM to include the following statement: "Category II and III operations are prohibited." (This may be accomplished by inserting a copy of this Directive into the AFM) 2. If, during the Requirement 1 (a) inspection, fault code "N1" or "Nm" is found, either replace the existing ILS receiver with a new or serviceable ILS receiver having the same P/N or with an ILS receiver that has been modified to P/N 066- 50006-1101 in accordance with AlliedSignal Electronic and Avionics Systems Service Bulletin (SB) M-4426 (RIA-35B-34-6) Revision 3 dated May 1998. 3. A RIA-35B ILS receiver P/N 066-50006-0101, that has been found to be discrepant (that is on which fault codes "N1" or "Nm" were found during an inspection of the internal fault memory) shall not be installed on any aeroplane unless the discrepancy has been corrected by modifying the ILS receiver in accordance with SB M-4426 (RIA-35B-34-6) Revision 3. 4. Replace all existing RIA-35B ILS receivers, P/N 066-50006-0101, with RIA-35B receivers that have been modified in accordance with SB M-4426 (RIA-35B-34-6) Revision 3 and that have had their P/N's converted to 066-50006-1101. This constitutes terminating action for the Requirement 1.a. repetitive inspection and allows the removal of the Requirement 1.b. placard, together with any required amendment to the Flight Manual Limitations Section on this subject. Note 2: FAA AD 99-10-14 Amdt 39-11167 refers. Compliance: 1. a. Remains unchanged from the original Compliance 1 as 'Prior to 2 October 1998 and thereafter at intervals not to exceed 64 flight cycles'. COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY SCHEDULE OF AIRWORTHINESS DIRECTIVES 1. b. If not previously accomplished in accordance with the original issue of this Directive, compliance is required no later than 20 November 1999. 2. Prior to further flight. 3. As of the effective date of this amendment. 4. Before 20 April 2000. This Amendment becomes effective on 27 October 1999. Background: The original issue of this Directive provided measures designed to ensure either certain aircraft operations were limited or that faulty ILS receivers were detected and replaced. These actions removed the likelihood of erroneous localizer deviations which could result in a landing outside the lateral boundary of the runway. This amendment provides a mandatory terminating action, minor editorial corrections and clarifies the Requirement 1 compliance. The original issue of this Airworthiness Directive became effective on 9 September 1998.