(2) Elbow The purpose of the elbow is to redirect the airstream into the APU plenum chamber. In order to reduce aerodynamic losses, 2 guide vanes are incorporated. It also functions as a resonator-type muffler. The design of the walls and their installation is identical to those of the diffusor. The guide vanes are on the entire external surface acoustically treated, their internal design is similar to that of the outer walls. They are assembled with the elbow side walls by means of bonded-in rails. A flexible fireproof seal at the elbow/APU junction minimizes air losses while providing a flexible interface. Drainage provisions are incorporated into the lower wall.
4. Power Supply____________ (Ref. Fig. 002)
5. Interface_________ The air intake system has an interface with the control and monitoring system (Ref. 49-61-00).
6. Operation/Control and Indication________________________________ (Ref. Fig. 002) The following components control the opening/closing of the air intake flap:
-
the MASTER SW pushbutton switch,
-
the APU main relay 4KD (APU MAIN) and
-
the ECB.
A.
Opening of the Air Intake
(1)
The following settings are required:
-busbar 301PP energized (carries 28V DC electrical power),
-
circuit breaker 1KD (ECB SPLY) closed,
-
circuit breaker 2KD (APU CTL) closed and
-MASTER SWITCH 14KD in the ON position.
(2)
When you push the APU MASTER SWITCH in the ON position:
-
the blue ON legend in the MASTER SW comes on,
-
the APU main relay 4KD is energized,
-electrical power is supplied to the ECB,
-
the ECB energizes the air intake flap actuator to open the flap.
-
the air intake flap actuator moves the flap into the 'OPEN'-position within approximately 20s,
-when the air intake flap actuator reaches the end position 'retracted' (flap in 'OPEN'-position), a 'FLAP OPEN'-signal is transmitted back to the ECB,
- on the lower ECAM APU system page the FLAP OPEN indication comes on.
R EFF : 001-049, 101-105, 107-107, 151-199, 49-16-00Page 7 201-210, Config-2 Aug 01/05
CES
Air Intake System - Schematic
Figure 002 (SHEET 1)
CES
Air Intake System - Schematic
Figure 002 (SHEET 2)
CES B. Closing of the Air Intake
(1)
Normal APU Shutdown Procedure
(a) When you release the APU MASTER SW pushbutton switch in the off position:
-
if the bleed air mode was used, a 60s cool-down cycle starts (counted from the bleed-air deactivation),
-
if no bleed air mode was used, no cool-down cycle is started,
-when the APU speed has decreased to below 7%, the ECB sends a 'FLAP CLOSE'-command to the air intake flap actuator for 30s.
-the air intake flap actuator moves the flap into the 'CLOSED'-position within approximately 20s,
-when the air intake flap actuator reaches the end position 'extended' (flap in 'CLOSED'-position), a 'FLAP CLOSED'-signal is transmitted back to the ECB,
-the APU main relay 4KD is de-energized when the 30s have expired,
-electrical power is disconnected from the ECB.
(2)
APU EMERGENCY STOP (Ground Signal)
(a)
In case the ECB receives an 'APU EMERGENCY STOP'-command for a minimum of 150ms, the following sequence occurs:
-the ECB 59KD shuts down the APU immediately (no cool-down cycle),
-when the APU speed has decreased to below 7%, the ECB 59KD transmits a 'FLAP CLOSE'-command to the air intake flap actuator,
-the air intake flap actuator moves the flap into the 'CLOSE'-position within approximately 20s.
-when the air intake flap actuator reaches its end position 'extended' (flap in 'CLOSED'-position), a 'FLAP CLOSED'-signal is transmitted back to the ECB 59KD.
(b)
After the MASTER SW has been set to the 'off'-position, the following sequence occurs:
-the APU main relay 4KD is de-energized,
-electrical power is disconnected from the ECB.
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