(25)
DV RST CMD/POS The first number in the DV RST CMS/POS display shows the percent the APUC tells the diverter valve to open. The second number shows the current position of the diverter valve. The difference between the two numbers must be less than 15%.
(26)
ECS DEMAND The ECS DEMAND is a percentage of a 1-9 volt signal sent from the zone temperature controller.
NOTE: The ECS DEMAND will always show 100% when all packs are
____ off. When a pack is on, the ESC DEMAND display will go to zero and then increase to the correct value. Only when all three packs are on, will the APU increase the IGV schedule.
(27)
GEN 1/2 LOAD The GEN 1/2 LOAD display shows the load in KW for the No. 1 and the No. 2 generator.
(28)
DC-A-CHG The DC-A-CHG display shows the APU battery charge in Amps.
NOTE: This data comes from the airplane systems, not the APUC.
____
(29) DC-V The DC-V display shows the voltage the of the APU battery.
NOTE: This data comes from the airplane systems, not the APUC.
____
B. To get access to the APU maintenance page, refer to this task: Obtain Airplane System Information (AMM 31.61.00/201).
4. Oil Quantity____________
A. APU oil quantity appears on both the EICAS status and maintenance page in white. If applicable a two letter message (magenta) is displayed next to the oil quantity. A message which appears as 0.50RF (refill) indicates that the APU oil quantity is less than 50% full. A message which appears as 0.22LO (low) indicates that the oil quantity is below 22% full.
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MAINTENANCE MANUAL
B. The table that follows gives the oil quantity indications you will see on the EICAS screen with a full oil tank of different types of oil:
EICAS APU OIL QUANTITY _______________________OIL INDICATION (FULL) TANK Castrol 5000 1.00 Castrol 325 1.00 Exxon Turbo 2380 1.00 Mobil Jet II 0.95 |0.05 Aeroshell 55 0.85 |0.05
C. AIRPLANES WITH THE HAMILTON STANDARD P/N 800485-2-010 APUC; When an oil quantity fault occurs, the EICAS oil quantity display will not show.
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747-400 MAINTENANCE MANUAL
APU EXHAUST SYSTEM - DESCRIPTION AND OPERATION
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General
_______
A. The APU exhaust system conducts the APU exhaust gases overboard, provides a thermal barrier to shield the APU compartment from exhaust gases, and reduces the exhaust noise level. The system consists of an outer exhaust duct, an inner exhaust duct, and an acoustic liner.
Outer Exhaust Duct (Fig 1.)
__________________
A. The outer exhaust duct consists of cylindrical sections, a conical transition, a leaf spring seal, and a bellows and nozzle assembly. The outer duct serves as the outer surface of the cooling air annulus and the support structure for the exhaust duct. The bellows and nozzle assembly at the forward end of the outer exhaust duct provides a flexible connection between the APU and the exhaust duct and contains a nozzle for inducing secondary airflow to cool the outer duct. A gap between the forward end of the inner exhaust duct and the outside surface of the nozzle form a cooling air ejector. A fitting in the bellows and nozzle assembly provides for fuel and water drainage from the duct. The outer duct leaf spring seal slides into a seal land attached to the airplane tail cone. The seal allows for thermal expansion of the duct and is the aft support for the exhaust duct. The forward end of the duct is attached to the APU exhaust port with a V-band clamp.
Inner Exhaust Duct (Fig 1.)
__________________
A. The inner exhaust duct consists of cylindrical sections, a conical transition, and Z-shaped circumferential baffles. The inner exhaust duct forms the inner surface of the cooling air annulus and provides baffled air spaces required for the operation of the acoustical liner. The inner exhaust duct is positioned concentric inside the outer exhaust duct and extends aft of the airplane tailcone. The inner exhaust duct carries the acoustic liner.
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