COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Boeing 747 Series Aeroplanes
AD/B747/80 Equipment Cooling System E30 Cooling Rack Orifice
Applicability: All Boeing 747-400 as detailed in the Requirement document. Requirement: Action in accordance with Boeing Alert Service Bulletin 747-21A2285. Compliance: Prior to 6 December 1990.
9/90
Background: One operator has reported three instances of insufficient equipment cooling system pressure in the E30 rack. Lack of sufficient cooling may cause overheating of the main transformer rectifier units resulting in no DC power output from the main TRU’s. Whilst limited DC power will still be available from the main battery and battery charger, loss of output from the main TRU’s will result in loss of many flight essential systems.