COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Embraer EMB-120 (Brasilia) Series Aeroplanes
AD/EMB-120/11
Amdt 1
AHRS Power Interruption 2/95
Applicability: All Brasilia model EMB-120, EMB-120RT and EMB-120ER aircraft, except aircraft with the following serial numbers:
120004 120006 to 120024 inclusive
120026 to 120030 inclusive 120033 to 120035 inclusive
120037 120040
Requirement: 1. Aircraft not equipped with an APU:
- trip (pull) circuit breakers CB 534 (AUX GEN 2 BUS CONTROL) and CB 535 (AUX GEN 1 BUS CONTROL) located in the right hand and left hand DC Relay Boxes respectively, and
b. install circuit breaker collars or equivalent to CB 534 and CB 535 to prevent their closure, and
c. install near CB 534 and CB 535 a placard stating `Do not close CB 534 or 535’ (appropriate CB number to be inserted on the applicable placard).
2. Aircraft equipped with an APU either:
- deactivate the AHRS/EFIS automatic power transfer system in accordance with the instructions for aircraft not equipped with an APU, or
b. change the Minimum Equipment List as follows:
- cancel item 24-30-1 `Engine Starter Generator’, and
ii. cancel item 24-30-2 `APU Generator’
3. Action in accordance with Embraer Service Bulletin 120-24-0008 Revision 3 dated 19 August 1994.
Note: CTA (Brazil) AD 94-03-01 Amdt 39-734 refers.
Compliance: 1 and 2. The compliance remains unchanged as prior to 5 July 1994.
3. Prior to 10 May 1995.
Background: The CTA has received a report of erroneous heading information being displayed on both EHSIs following certain combinations of electrical system failures, which are not considered improbable.
The original issue of the Directive provided temporary procedures which ensured that heading information was available following these failures.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
This amendment provides terminating action for the temporary procedures.