IAMS Flashcards
During ground operation, what is the priority bleed source for engine starting?
APU
What are the two functions
of the ram air system?
- Provide cooling for the pack heat exchangers
2. Provide alternate source of fresh air to the airplane during unpressurized flight
During normal flight operations, what is the purpose of engine bleed air?
Environmental control, wing and cowl anti-ice
What happens to the packs when the
DITCHING switch/light is used?
The packs shut down
How many outflow valves are there,
and how are they operated?
Two. They are electrically operated.
What cabin pressure information displays on the STATUS page when the pressurization
MAN mode is selected?
Both outflow valve position indicators and a cabin rate analog gauge display
Which engine compressor stages
supply bleed air?
5th-stage low-pressure port and
8th-stage high-pressure port
What function is lost when the TRIM AIR is off?
Zonal temperature control
What are the pack temperature range limits during manual operation?
+5°C to 60°C
How long does the cabin pressure controller retain the prepressurization sequence altitude after takeoff?
10 minutes
What is the function of the flow control valves (FCVs)?
The FCVs modulate to provide a preset flow schedule to the packs, and to close / to isolate a pack
What are the two cabin rate modes available on the PRESSURIZATION panel?
Normal mode:
500 ft/min up and 300 ft/min down;
high mode:
800 ft/min up and 800 ft/min down
What is the maximum cabin relief differential pressure?
10.73 PSI
What is the maximum negative relief differential pressure?
-0.5 PSI
What is the maximum OAT for air-conditioning operation using the APU as the bleed source?
45°C
What is the purpose of safety valves?
Provide overpressure /
negative pressure relief
When would a pilot need to manually set the landing elevation?
QFE operations,
Airport not in the FMS database
At and below which altitude can the ram air valve be opened?
15,000 feet
Can one engine supply two AC packs simultaneously?
No. The BMC prevents two-pack operation from a single engine source.
At what cabin altitude will an EICAS
warning message display?
9000 feet
At what cabin altitude will an EICAS caution message display?
8200 feet
What is the maximum altitude
for AUX PRESS operation?
41,000 ft
How are bleed-air leaks monitored in the aircraft?
Dual loops
In a normally pressurized aircraft as per the pressurization table, what is the cabin altitude for an aircraft at 51,000 ft?
5670 ft and 7230 ft (not incorporating CPC mod)
What occurs automatically when
a bleed-air leak is detected?
The BMC isolates the affected manifold by closing the appropriate valves
What is the maximum altitude for selection of the EMER DEPRESS switch/light?
15,000 feet
What are the two modes of operation
with the cabin pressure control system in AUTO?
PRIMARY mode (predictive): uses FMS to schedule
cabin cruise altitude, and SECONDARY mode (reactive):
pressure altitude and vertical speed
May both packs be operated in manual mode simultaneously?
No. The AFM limits manual pack operation to single pack.
What is the function of the air conditioning units?
To decrease the air temperature
How is the landing elevation manually set?
LDG ELEV switch to MAN, then UP/DN switch to set the elevation
Name the conditions that would cause a pack to shut down.
Bleed failure, engine shutdown, engine starting, ditching selection, pack inlet overheat, compressor discharge overheat, pack discharge overheat/under pressure
What happens to the outflow valves when the DITCHING switch/light is used?
OFVs commanded open, aircraft depressurizes,
OFVs driven closed
What is the maximum pressure differential during initial landing (touchdown)?
1.0 PSI
Under which condition would
AUX PRESS be used?
Every time the two packs are nonfunctioning and pressurization is required
How is landing elevation set during QFE operations?
The LDG ELEV switch is selected to MAN,
and the LDG ELEV must be set to 0 ft
What is the maximum pressure differential
during taxi and takeoff?
0.1 PSI
