When will the HYD 1 HI TEMP EICAS caution message be displayed?
When the hydraulic fluid temperature increases to 100°C
When will the hydraulic SOV automatically close?
When fluid temperature reaches 125°C
What happens to the hydraulic system during an engine flameout?
FADEC depressurizes the respective EDP to reduce torque loads on the engine and facilitate a windmill start
When will the electric hydraulic pump #1 operate automatically in flight?
- EDP or engine fail
* Flaps any position greater than 0°
When will the electric hydraulic pump #1 operate automatically on the ground?
Flaps selected to any position greater than 0° and:
•Thrust levers set to takeoff thrust or
•Ground speed greater than 50 kt
What comprises hydraulic system #1?
- One reservoir
- One engine driven pump (EDP)
- One electric hydraulic pump
- One accumulator
Can hydraulic fluid be transferred between each system?
No
What is included in the hydraulic system 2 that is not on system 1?
Power transfer unit (PTU)
What is the PTU?
- Power transfer unit
* Assists the landing gear retraction or extension, should the right engine fail or EDP fail
What does hydraulic system 3 power?
- Primary flight controls
- Elevator
- Rudder
- Ailerons
During an electrical emergency what happens to the hydraulic 3 overheat protection system?
It will be inhibited as well as the EICAS messages
What is normal hydraulic pressure?
3000 psi
How many hydraulic pumps are on the airplane?
- 6 total
- 2 EDPs
- 4 ACMPs
When will the ACMP 1 or 2 automatically activate?
On ground:
•Flaps > 0 and
•Thrust levers set to T/O
•Groundspeed > 50 kts
In flight:
•Engine failure or EDP failure
•Flaps > 0
When will hydraulic system 2 automatically activate?
- Engine 1 running and parking brake released
* During engine 1 start if parking brake has been applied within the last 6 mins
What happens to the lettering on the hydraulic MFD page in the event of a system failure?
The size of the letters increases
What is the pump unloaded valve?
•Reduces discharge of the ACMP 3A when the RAT deploys
What is the flow limiter valve?
- Reduces the amount of flow provided by the ACMP 3A
* Prevents the RAT from stalling
