AD/B747/190 Amdt 1 - Instrument Landing System Receivers (Cth)

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.