Water & Waste

Question 1

What is the capacity of the water system?

Answer 1

2 x 20 gal tanks

Question 2

What switches control power for the water & waste system?

Answer 2

CABIN / GALLEY MASTER switch on the cockpit overhead panel as well as CABIN/GALLEY switches in SSPC

Question 3

Name the four (4) places where the water system is controlled.

Answer 3

Touch screens in galley and vestibule, external service panel, and the tank enclosure

Question 4

How many toilets are on the aircraft?

Answer 4

Two

Question 5

What’s the capacity of the waste tank?

Answer 5

18 gallon storage tank with a 12 gallon usable capacity

Question 6

How is the water system pressurized?

Answer 6

With an air compressor, or engine or APU bleed air

Question 7

How many drains are there and where are they located?

Answer 7

There are two drains on the bottom of the aircraft: a drain mast located in back and penetration port located forward. Water drains out the back in flight due to nose attitude and differential pressure, and drains out the front on the ground due to nose attitude.

Question 8

What are the three requirements for water system operation?

Answer 8

1) select the CABIN / GALLEY master switch to ON,
2) the GALLEY POWER switch in the MCDU (SSPC system) must be ON, and
3) the water system must be selected to ON (green indication) at the galley touch screen

Question 9

What happens when the water system is selected to ON with cabin temperature below 34°F?

Answer 9

The system heaters are selected ON and operation of the water system is delayed for approximately 20 minutes

Question 10

What’s the difference between a line drain and system purge?

Answer 10

A line drain allows all water in the supply lines, lavatory water heaters and galley water heater to drain from the aircraft. A system purge removes all water from the supply lines and the water tanks.

Question 11

How much time is required to purge

the water tanks?

Answer 11

Approximately seven (7) minutes per tank

Question 12

If you initiate a line drain or system purge in flight, when is the procedure completed?

Answer 12

The process won’t be complete until after landing since the forward supply/drain valves don’t open until weight-on-wheels.

Question 13

True/False: A leak check is performed to isolate a leaking faucet, water heater, valve, or line downstream of tank valves.

Answer 13

True

Question 14

What happens if the water system is used during the 15 minute leak check?

Answer 14

It invalidates the results

Question 15

What’s the normal fill time for each water tank?

Answer 15

Approximately seven (7) minutes per tank

Question 16

What generates the vacuum for flushing the toilet?

Answer 16

Cabin differential pressure or a vacuum generator. The vacuum generator is required for differential pressure <6psid (i.e. below approximately 16,000 ft).

Question 17

Can you flush the toilet on the ground without AC power?

Answer 17

No

Question 18

Regarding the toilet flushing, what happens if the normal system fails to function properly (e.g. flush switch failure)?

Answer 18

A separate manual flush handle can momentarily open the flush valve