Hydraulic Flashcards
At which pressure do the hydraulic systems operate?
3000 psi
At which temperature will we have HYD 1 HI TEMP?
100°c
What happens if the hidraulic fluid reaches a temperature of 125°C?
The SOV automatically actuates, isolation the corresponding EDP.
What happens if the hydraulic fluid reaches 145°C?
It will pop out HYD 1(2) OVERHEAT, you have to manually close the SOV.
Where is the hydraulic fluid temperature and quantity measured?
At the reservoir
I’m which cases, on ground, does the ELECTRIC HYDRAULIC PUMP 1 works?
- Flap selected greater than 0°
- Thrust levers set to take off thrust
- Airspeed grater than 50 kts
Also, when thrust levers are set to TOGA the pump will be activated for 60” to avoid abrupt hydraulic pressure variations in case of OEI.
In which cases, in flight, will the ELECTRIC HYDRAULIC PUMP 1 be activated?
- EDP or engine fail
- Flaps selected to any position different than 0°
And during landing the pump will be activated for 1’ in case of engine failure, to prevent pressure variations
Which type of current use the electric hydraulic pump 1 and 2?
AC current
Pump 1 ACBUS2; Pump 2ACBUS1
(Sono scritte giuste)
The activation of ELECTRIC HYDRAULIC PUMP 2, is similar to the pump 1. What is the difference on ground?
On ground will be automatically activated when:
-engine 1 running and parking brake released.
-During engine 1 start (once N2 reaches 40%) if parking brake has been applied in the last 6 minutes. It will be then automatically turned off after 6’ have elapsed from brake application.
How is the PTU connected between which system, and what is it purpose?
It consists of a hydraulic motor in sys1 which drives a hydraulic pump in sys2, it’s purpose is to assist landing gear retraction or extension in case of eng 2 failure or EDP2 failure.
In which case, apart from engine2 fail, will the PTU be activated?
When all the following conditions are met with the aircraft in flight.
- Flaps not 0 or landing gear not up and locked
- EDP1 not fail
- Hydraulic reservoir 2 qty above 12%
Hydraulic sys 3 has the same protection of sys1 and 2?
Yes it has overheating protection, but in case of electrical emergency the protection system and the EICAS messages will be inhibited, preventing the crew to switch off the only source of hydraulic power available
What bus feed the ACMP 3A and 3B?
ACMP 3A is ACESS BUS
ACMP 3B is ACBUS 2
When does the ACMP 3B work?
When the ACMP 3A fails, it is its backup.
