Pneumatics Flashcards
what systems use the HP pneumatics
- air conditioning
- engine starting
- wing anti-ice
- hydraulic and water reservoir pressurisation
not included: - fwd/aft cargo heating
- FTIS (Fuel Tank Inerting System)
what are the sources of HP air
- eng bleed
- APU bleed
- external HP air
how is the bleed valve operated and controlled
- pneumatically operated
- electrically controlled
what are the options for bleeding the air from the engine
- Intermediate pressure stage of the HP compressor (via check valves); OR
- High pressure stage of the HP compressor (via HP valve)
when does the HP valve open
- low engine speed
- bleed pressure and or temperature insufficient
what pressure does IP and HP regulate to
36psi +/- 4psi
when does the HP valve automatically close (pneumatically and electrically)
- pneumatically:
1) low upstream pressure
2) excessive upstream pressure - electrically:
1) bleed valve is closed
2) o/press upstream of HP valve, and;
a) wing AI - off
b) 2 packs - on
c) alt > 15,000’
what kind of valve is the bleed valve
- shutoff
- pressure regulating
what pressure does the bleed valve regulate to
45psi +/- 5psi
what pressures may the bleed valve fluctuate to and max peak to peak
38psi to 56psi (16psi peak to peak)
when is the bleed valve automatically closed pneumatically and electrically
pneumatically: - upstream psi < 8 - return flow electrically: - ENG BLEED Pb - OFF - ENG FIRE Pb - pressed - BMC detects: a) overtemperature b) overpressure c) leak d) open starter valve e) APU bleed - ON f) ENG SHUTDOWN (3332 onwards VNF)
if pressure regulation fails when does the overpressure valve automatically close
75psi
what is the exception to the ENG bleed valve closing if the APU bleed is ON
if the APU bleed is on and the XBLEED valve is SHUT, ENG 2 BLEED will remain OPEN
what is the purpose of the pre-cooler
regulated the ENG bleed air temperature
what type of exchange is the pre-cooler
air-to-air
what temperature does the pre-cooler try to regulate to
approximately 200 degrees
what controls the amount of cold air passing through the pre-cooler
the fan air valve which bleeds air from the FAN of the engine
what happens to the fan air valve in the absence of pressure
spring-loaded closed
what type of valve is the APU bleed valve
shutoff
what happens to the rest of the bleed system if the APU bleed sw is ON
- both ENG BLEED valves close
- XBLEED OPENS
when does the APU BLEED valve automatically close
EDES for all
- APU leak
- left wing leak
- pylon 1 leak
how is the XBLEED valve controlled
2 electric motors:
1st during automatic operations
2nd during manual operations
when does the XBLEED valve automatically open and close
- opens if APU BLEED - ON
- closes if leak detected (except during engine start)
where are leak detection systems in place
- APU
- wing
- pylon
which leak detection systems use single and double loops
- single:
a) pylon
b) APU - double:
a) wing
when does an alert occur for the double leak detection systems
- when both detect a leak; OR
- when 1 loop detects a leak and the other loop is U/S
what happens following a wing leak
- associated ENG BLEED valve - closes
- ENG BLEED FAULT lt - illuminates
- XBLEED valve closes (EDES)
- APU BLEED valve - closes if LHS affected (EDES)
what happens following a pylon leak
- associated ENG BLEED valve - closes
- ENG BLEED FAULT lt - illuminates
- XBLEED valve closes (EDES)
- APU BLEED valve - closes if LHS affected (EDES)
what happens following an APU leak
- APU BLEED valve - closes (EDES)
- APU BLEED Pb fault lt - illuminates
- XBLEED valve - closes (EDES)
what leak detection loops does BMC 1 receive
- pylon 1
- APU
- loop A of both wing loops
what leak detection loops does BMC 2 receive
- pylon 2
- loop B of both wing loops
if 1 of the BMCs fail what does the other BMC monitor and issue ECAMS for
- overpressure
- overtemperature
- wing leak
what is lost if 1 BMC fails
- FAULT lt on OVHD PNL
- associated BLEED valve does not close automatically
- ENG BLEED LEAK warning for associated engine
- APU BLEED LEAK warning if BMC 1 is failed
with the ENG BLEED Pb sw in the on position, when will it open
- upstream psi > 8
- APU BLEED Pb - OFF or APU bleed valve closed
- no onside wing/pylon leak and no overpressure/overtemperature
- ENG FIRE Pb not pressed
- ENG start valve closed
when does the ENG BLEED Pb fault light illuminate
- overpressure downstream of bleed valve
- bleed air overheat
- wing/pylon leak on related side
- bleed valve not closed during eng start
- bleed valve not closed with APU bleed ON
extinguishes when ENG BLEED Pb is OFF and the fault has disappeared
what are the indication on the BLEED SD page regarding the precooler
- pre-cooler inlet pressure
- pre-cooler outlet temperature
when does the precooler pressure indication turn amber
- below 4psi
- above 57 to 60
when does the precooler temperature indication turn amber
- overtemp:
a) 290 for more than 5s
b) 270 for more than 15s
c) 257 for more than 55s - low temperature: (only in flight)
below 150 degrees with wing AI ON and PRV OPEN
when does the APU BLEED LEAK ECAM appear
APU bleed leak detection loop detects a temperature above 124
when does the AIR ENG 1(2) BLEED FAULT ECAM appear
engine is running and:
1) ENG bleed air press> 57-60psi, OR
2) engine bleed air temperature>
a) 290 for 5s
b) 270 for 15s
c) 257 for 55s
when does the AIR ENG 1(2) BLEED LO TEMP ECAM appear
bleed air temperature < 150 degrees in flight with wing A-ICE Pb - ON
when does the AIR ENG 1(@) BLEED HI TEMP ECAM appear
pre-cooler outlet temper > 240
when does the AIR ENG 1(2) BLEED LEAK ECAM appear
pylon bleed leak detection loop detects a temperature > 204 and the engine is running
when does the AIR L(R) WING LEAK ECAM appear
when both wing bleed leak detection loops detect a temperature above 124
