02 Air Conditioning/Pressurization Flashcards
Packs psi in Low mode and High mode
24 psi Low mode
39.5 psi High mode
When is a pack in High mode?
Airborne during single-pack operations, or on ground with APU supplying bleed air.
(39.5 psi)
Only 2 single pack situations triggers auto HI mode on working pack, without depressing the failed packs switch/light.
Overpressure or Overtemp failures
Packs receive bleed air from where?
Engine 10th stage, APU or external source
What percentage is the packs air is distributed to cockpit and cabin?
L Pack: 60% cockpit 40% cabin
R Pack: 100% cabin
What busses are the L and R pack on?
L Pack: DC Ess bus
R Pack: DC bus 2
Air conditioning:
NORM mode temp
STBY mode temp
MAN mode temp
What triggers control valve to full hot or full cold?
15 - 32°C
2 - 82°C
2 - 93°C
3°F difference between actual and selected temperature
Cockpit heat temp range og
Hvad består det af?
38 - 49°C
A fan, an Electric heating element and a duct sensor
Cockpit heat:
When activates Fan speed protection?
When activates Fan overheat protection?
When fan fails to attain 60% speed for more than 2 seconds.(CKPT HEAT FAN FAIL status on EICAS)
When temperature in the heater reaches 65°C the heating element shuts off (fan continues to help cool down the heater).
How is cabin pressure achieved?
By controlling outflow through 2 outflow valves which are controlled by the CPC (cabin pressure controller).
What module provides pressure data to the DCUs (data concentrator units)?
CPAM (cabin pressure acquisition module). Data is then displayed on EICAS.
CABIN ALT caution illuminates at what cabin altitude?
Between 8.500 and 10.000 ft
CABIN ALT warning illuminates at what cabin altitude?
When cabin alt exceeds 10.000 ft during low altitude airfield operation or
14.500 ft during high altitude airfield operations.
DIFF PRESS warning illuminates when..?
Cabin pressure differential exceeds 9.0 psi
If CPAM fails, do you loose operation of cabin pressure controller?
No. Failure of CPAM does not affect the operation of the cabin pressure controller.
Cabin pressure controller (CPC) receives input from …. to control outflow valves?
S3 Static port (ambient pressure)
Cabin pressurization selector
Thrust levers
Weight on wheels relays (WOW)
The outflow valves will automatically open when the cabin differential pressure exceeds …?
9.1 +- 0.1 psid
Cabin pressurization operation:
Flight mode, with auto RATE knob selected at the PIP mark 🔽, the cabin rate will climb at … or descend at … ?
climb at 500 fpm and descend at 300 fpm.
CKPT and CABIN temp mode selector
NORM:
- What sensor?
- What temp range?
Fan and duct sensors
15°C to 32°C
CKPT and CABIN temp mode selector
STBY:
- What sensor?
- What temp range?
Duct sensor inputs only
2°C to 85°C (82 C??)
CKPT and CABIN temp mode selector
MAN:
- What sensor?
- What temp range?
No sensor inputs
2°C to 93°C
Pressurization:
Rate selector knob commands the CPC ( Cabin Pressure Controller).
Rotate to PIP means how many FPM up and down?
500 FPM up (climb) and 300 FPM down (descent)
Where are the Air Conditioning Units (packs) located?
Aft equipment bay.
Air conditioning/pressurization receives bleed air from …?
10th stage bleed air from the engines, APU or external bleed air.
Rate selector knob commands the CPC ( Cabin Pressure Controller).
How many FPM up and down is the range?
Selectable from 0-2500 FPM UP and
0-1500 FPM Down
The outflow valves operate to maintains a differentail pressure from * to * psid?
0 to 8.8 psid
At what minimum pressure differentail will the outflow valves open to protect the fuselage from imploding?
- -0.5 psid
What triggers:
“DIFF PRESS” WARN
“CABIN ALT” CAUTION
“CABIN ALT” WARN
9.0 psi
8,500 feet
10,000 feet (14,500 high ALT OPS)
Cabin altitude and diff press at FL410 (max operating altitude)
6,800 feet cabin alt
8.8 psid
