Oral Study Questions Flashcards
When doing the walk around what is the pressure gauge under the right wing displaying?
The gauge under the right wing is showing accumulator pressure. This is maintained by nitrogen gas keeping pressure within the system. This is not the same pressure as what is shown in the cockpit as the accumulator can lose its pressure (bleed out) while the parking brake maintains what is indicated in the cockpit.
If the pressure gauge under the wing does not meet the 500/1000psi requirements MX must be called to recharge the system.
How do you check the parking brake pressure?
The only accurate indication is located on the FO’s MFD.
When doing the walk around you notice the gauge under the right is below 500psi. Can you charge the system by using the manual pump located in the #2 nacelle?
No. The gauge under the wing is only showing the pressure in the accumulator which is maintained by a nitrogen charge. If the pressure is low MX must be called to recharge the system (add nitrogen).
Describe the batteries of the aircraft
Three 24v 40amp/hr batteries. You have your main, aux, and standby.
When I flip the battery master switch on what does it do?
It directly connects all three batteries to the Essential DC buses
What happens when I select the main, aux, and standby switches on?
The main connects the main battery to the right main bus.
The aux connects the aux battery to the left main bus.
The standby connects the standby battery to the left main bus allowing a “one-way” power flow for battery recharging only.
When you go to start an engine what batteries are providing power?
The main and aux batteries assist with engine starts. The standby battery provides DC power to the HOT battery bus.
When looking in the nose compartments which batteries are which?
The main and aux batteries are located on the bottom. The forward battery is the main with the aux behind it.
The standby is located on the top.
Describe the generators on the aircraft
There’s five located on the aircraft. Each engine has a DC and AC gen. The APU has a DC gen. Each generator is capable of supplying 400amps of output.
How are the DC and AC gens cooled?
The DC gens are air cooled. The AC gens are oil cooled.
Describe how the DC gens work
The engine driven DC gens are driven by the accessory gearbox and monitored by the generator control unit (GCU). They act as starter-generators. During engine start when Nh reaches 50% the GCU converts from the starting to the generating mode. They then supply power to their associated main DC bus.
How do the AC gens work?
The AC generators provide 115v AC power to the aircraft through the left and right variable AC buses. The AC generators come online once the engines are operating over 440rpms.
What do the AC gens power?
The AC gens provide power to the de-ice/anti-ice systems (except pitot static tube #3), your standby hydraulic pump (hyd sys 1), your two TRUs, both of your aux fuel pumps, and your galley loads.
Can your AC system provide support for an engine start?
AC power will not support engine starts.
How many TRUs are there and what they?
There are two TRUs on the aircraft. They convert AC to DC power. The TRUs can output 300 amps each and will allow the AC gens to power the DC systems in the event of failures.
Describe the fuel tanks on this aircraft
There are two tanks and each has three sections. The surge bay, main tank, and collector bay.
The surge bay is used for tank venting through two NCAA vents. One vent allows for fuel overflow while the other provides positive pressure within the tank. Any fuel that flows into the surge bay in flight is siphoned back into the main tanks.
The main tank simply stores the bulk of the fuel and delivers that fuel to the collector bay.
The collector bay provides a steady supply of fuel to the engines.
How much fuel does each tank hold?
5862 lbs of fuel per tank.
When will you get a “tank fuel low” light?
When the level of fuel drops below 305lbs