Systems: Hydraulic

Question 1

How many hydraulic systems are on the ERJ-145?

Answer 1

2 independent hydraulic systems

Question 2

What items are on hydraulic system #1?

Answer 2

LANDING GEAR

Question 3

What items are on hydraulic system #2?

Answer 3

EMERGENCY/PARKING BRAKE

Question 4

What is the minimum fluid quantity required for dispatch?

Answer 4

1 liter

Hydraulic fluid quantity can be monitored on the MFD.

Question 5

What is the priority valve and what does it do?

Answer 5

The priority valve operates automatically and ensures normal operation of the hydraulic system during engine or engine-driven hydraulic pump failure.

If hydraulic system #1 is being powered by the electric pump and the landing gear is commanded down, the priority valve gives hydraulic pressure priority to the flight controls. Gear operation is accomplished through stored accumulator pressure or standby pump operation.

Question 6

When do the standby hydraulic pumps operate?

Answer 6

The pumps normally operated in the AUTO mode, turning on whenever associated hydraulic pressure drops below 1600 psi or when N2 drops below 56.4%. (The pumps will also operate if selected in the ON position.)

Question 7

If an engine fails on takeoff, will the hydraulic systems be affected?

Answer 7

If the electric standby hydraulic pumps are in AUTO, neither of the hydraulic systems will be lost and normal operation will be possible.

Question 8

How are the main hydraulic pumps driven?

Answer 8

By the N2 via the tower shaft. The engine-driven pumps are a part of the accessory gear box on each engine.

Question 9

Prior to conducting the hydraulic test, what EICAS message should be present?

Answer 9

STEER INOP