ATA 21 - Air Conditioning / Pressurization / Ventilation

Question 1

What are the consequences of the primary channel failure in the zone controller ? Of the secondary channel ? Of both ?

Answer 1

Primary Channel: secondary takes over. Pack 1 for cockpit and pack 2 for cabin. 24 °C each. Hot air valve closed
Secondary Channel: no backup available
Both: 20°C pack1 and 10°C pack 2

Question 2

What are the conséquences of a pack controller, primary channel failure ? secondary channel failure ? Both ?

Answer 2

Primary: pack flow fixed at the current setting
Secondary: backup lost
Both: Pack outlet temperature is controlled to between 5 and 30 deg C by the anti-ice valve

Question 3

Bleed air supplied from the APU (APU bleed valve open), which pack flow is automatically selected ?

Answer 3

High

Question 4

When does normal cabin air pressurization occur?

Answer 4

During take off roll

Question 5

When does normal depressurization is completed ?

Answer 5

1 min after landing

Question 6

Max altitude for Ram Air ?

Answer 6

10 000ft

Question 7

Cabin pressure limitation with ram air utilisation ? Outflow valve position ?

Answer 7

Cabin differential pressure 1psi max. Outflow valve open at 50% if in auto mode.

Question 8

General description of Air conditioning system ?

Answer 8

Cf diagram

Question 9

Temperature corresponding to temperature selector COLD, NORM, HOT ?

Answer 9

18, 24, 30 °C

Question 10

Description of a Pack ?

Answer 10

Cf diagram

Question 11

Pack controller closes valve when :

Answer 11

• IGN / START ( closed until 2nd engine start or 30s)
• ENG FIRE PB
• DITCHING PB
• no air / overheat / overpressure

Question 12

When pack air intake and outlet valves close ?

Answer 12

At take off
At landing (until < 70 kt + 20s)

Question 13

Pack controller primary channel failure consequences ?

Answer 13

Works on secondary channel
Not optimized, previous flow is frozen

Question 14

Description of avionic ventilation system ?

Answer 14

Cf diagram

Question 15

How many cabin pressure controller are they ?

Answer 15

2, cycle every landings

Question 16

Maximum cabin rate of descent ?

Answer 16

750 ft /min

Question 17

Excess cabin altitude alarm at which altitude ?

Answer 17

9550 ft

Question 18

No smoke, seat belt, Exit lights automatically ON at which cabin altitude ?

Answer 18

11300ft

Question 19

Number of safety valves and max cabin pressure value ?

Answer 19

2 safety valves, 8,6psi

Question 20

CPC 1 has a back up independent power supply. True / False ?

Answer 20

True

Question 21

The lavatory/galley extract fan operates:
a.
Continuously when electrical power is available
b.
Only on the ground
c.
Only in flight

Answer 21

A

Question 22

If bleed air is being supplied by the APU or if one pack fails; pack flow will go to what rate?

Answer 22

High

Question 23

When either the BLOWER or EXTRACT switches are in OVRD; air from the air conditioning system is added to ventilation air. True or False ?

Answer 23

True

Question 24

What is the number of occupants below which you select Pack flow LO ? A318,A319, A320,A321

Answer 24

A321: 168 (ECON)
A320: 141
A319: 138
A318: -

Question 25

Following an ECAM CAB PRESS SYST 1 AMBER FAULT. SYSTEM 2 takes over automatically without crew action. True or False ?

Answer 25

True

Question 26

During landing run PACK AIR FLAPS open when speed is less than XX kts ?

Answer 26

70kts + 20s

Question 27

The cabin zone temperature sensors are ventilated by the air extracted by the lavatory and galleys extraction fans. True or False ?

Answer 27

True

Question 28

The outflow valve is powered by how much electric motors ?

Answer 28

3 2 for auto control 1 for manual control

Question 29

Consequence of a ACSC (Air Conditioning System Controllers) dual lane failure ? Of a single lane failure ?

Answer 29

Single Lane: none Both : Pack lost and hot air reg press valve closes

Question 30

If Pack flow is selected to LO and it is unable to cool down at the desired temperature, what does it do ?

Answer 30

NORM

Question 31

In case the AC is equipped with Air System Controller (ASC) instead of zone + pack controllers, which ASC controls which zone ?

Answer 31

ASC1 = cockpit ASC2= cabin

Question 32

If bleed flow is too weak to sustain pack demand for cabin temperature, zone controller ask for higher IDLE. True or False ?

Answer 32

True

Question 33

in case ECAM requires that during final app VS CTL …. FULL UP, at which altitude do you perfom the action ?

Answer 33

2500ft AAL