additional questions Flashcards
How is bleed air intially cooled after passing through the engine bleed air valve?
it is intially cooled by air that routes from the engine fan air to a pre cooler that then cools the bleed air before in continues into the manifold. there is a termostat control that controls the pre cooler valve to regulate the bleed air temp within limits
is 9th stage bleed air hotter than 5th stage?
yes, higher temp and pressure, pre cooler will require more cooling air at this time
where are the temp sensors and pressure sensors that turn the BLEED TRIP OFF light
over pressure is prior to the bleed air valve, over temp is after the bleed air valve and after the pre cooler
The APU bleed valve is electricall controlled (what system) and (blank operated)
DC / pressure
During ground use of engine anti icing what position should the APU bleed air valve be in?
closed, this prevents the APU from backpressuring the 9th stage valve, if the 9th stage valve were to close there might not be enough engine bleed air for cowl anti icing
What does the dual bleed help remind the pilot?
it reminds you that if the APU check valve were to fail you backpressure the APU and DON would be pissed
in order for the APU to provide bleed air what requirements must be met?
the APU must be running at over 95% RPM and the APU has been running for 1 min
How are the deflector doors for the Ram air system controlled?
electrically, and are controlled by the air/ground sensor
How are the heat exchangers in the pack system cooled when on the ground or during slow flight?
Ram air door full open and if needed there is a shaft that comes of the air cycle machine into the ram air duct, this shaft has a fan on it that helps cool the heat exchanger
the zone temp controllers (cold setting) (warm) (auto)
65F / 85F / 70F
With trim air OFF, how are the zone’s for airplane cooled?
left pack air temperature for the flight deck, right pack does the average for the FWD and AFT areas
two controllers are used to control the trim air modulating valves, explain what is on each controller
left controller: aft cabin temp control, back up flt deck zone temp control
right controller: primary flt deck and fwd cabin
During single pack operating with trim air ON, how is the zone temp controlled?
it is the same as normal pack operation
during single pack operation with trim air OFF, how is zone temp controlled?
the single pack will try to satisfy the avg of all 3 zones
if all temp controllers are selected to OFF, what will the packs attempt to deliver TEMP wise
left pack to flt deck = 75F
right pack to fwd /aft = 65F
if a zone temp light illuminates what happens?
the associated trim air modulating valve closes, trip reset will reset this
if a zone temp light illuminates during recall what has happened?
failure of a temp controller
if all zone controls and primary pack control fail, the standby pack control commands the packs to produce what temperature
the standby pack control will command the packs to produce temps that will satisfy the the AVG temp demand of the two cabin zones. in addition the flight deck zone temp selector will have no effect on the standby pack controls.
case in point use the FWD and AFT zone temp controls to get the temp you want
the temperature sensors in each pack are located where?
located at the compressor discharge and the turbine inlet
the FWD and AFT main deck shutoff valves are normally in what position?
normally open but can be closed to shutoff air to the cargo compartment.. they are closed by the DEPR switch on the cargo fire panel, the time to close the valves depends on outflow valve position and altitude
pressing the DEPR switch closes the FWD and AFT main deck shutoff valves, it will also do what?
it will open the mix manifold exhaust shutoff valve, discharging the mix manifold air below the floor and above the front spar
The normal supply fan does what for E/E cooling?
what about the exhaust fan?
the supply fan pushes are through the control stand and instrument panels which eventually ends up in the E/E bay
the exhaust fan draws air through the E/E compartment
(E/E) if the airflow is not adequate enough for the supply or exhaust fans what happens air? ground?
in the air: the associated OFF light illuminates along with overhead “OFF’” light and master caution
on the ground: in addition to the above a horn will sound in the nose gear wheel well
how does the “OFF” light work for the fans? E/E
The off light is activated by a thermal “no-airflow” detector.
if there is lackoff cooling airflow over the small heater, the small heater will cause the detector to sense the lack of airflow and the OFF light will come on.
selecting the alternate fan should cause the airflow to be restored within 5 seconds the light will go out
If you are on the ground what happens the E/E exhaust air? what about in the air?
on the ground or low cabin differential pressure the exhaust is ducted overboard through the overboard exhaust valve.
in the air when the cabin differential air is high, the overboard exhaust valve is closed and the exhaust is routed around (NOT INTO) the foward cargo compartment. the warm air around the forward cargo compartment keeps the compartment liner warm. THIS AIR IS THEN DISHCARGED OVERBOARD VIA THE OUTFLOW VALVE
the APU is capable of providing bleed air to how many packs? ground and air?
2 on the ground, 1 in the air.
Why do we not select HIGH flow for takeoff and landing (PACK)
single engine performance is based upon low flow
what controls the temperature of the pack? (think valve, there are two of them)
the postion of the primary pack temperature control valve, incase of failure of the primary there is a standby pack temperature control valve
what is on the left and right electronic controllers regarding packs?
Left: L ram air control, L primary pack control, R standby pack control
Right: R ram air control, R primary pack control, L standby pack control
if both the primary and standby pack controls fail what happens?
the pack will continue to operate without control unless or until it is tripped off due to excessive pack temperatures
how does the pressurization controller know the landing alt for the airport you are departing?
the air ground sensor and then sensed actual cabin altitude
when does the airplane start to pressurize on the ground?
when the throttles are advanced to achieve n1 greater than 60% and N2 greater than 89%, this makes the transition to pressurized flight more gradual
when will you get an OFF SCHED DESCENT light?
if the airplane begins a descent without reaching the planned cruise altitude. the controller will then automatically program the landing alt to the takeoff field elevation
what are the constant cabin altitude differential pressures?
at or below fl280 = 7.45
fl280 to fl370 = 7.8
above 370 = 8.35
after landing when will the outflow valve go full open?
after landing when the N1 is less than 50%
an AUTO FAIL will illuminate for ?
loss of DC power controller fault outflow valve control fault excessive dif pressure >8.75 excessive rate of cabin pressure change high cabin altitude (15800)
when will the overboard exhaust valve open in flight?
it will open if either pack switch is in HIGH, this allows for increased ventilation in the smoke removal configuration
how does air get to the lower cargo compartments?
cabin air is drawn through foot level grills, down around the cargo compartment area where it provides heating and then discharged overboard
The ADIRU provide what to the automatic pressurization controllers?
static pressure, barometric corrected altitude, non-corrected altitude and calibrated airspeed
how is the outflow valve powered?
DC motor, Man mode has a seperate DC motor that moves at a slower rate
the differential pressure is limited by what?
two pressure relief valves to a limit of 9.1
what provides negative pressure relief?
negative relief valve, the door seals also act as a negative pressure relief protection
what is the max differential pressure for takeoff and landing?
.125 PSI
how are the windows electrically powered?
#1 AC transfer bus = L1, R2, L3 #2 AC transfer bus = R1, L2, R3