13 - Hydraulics

Question 1

Why do we pressurize system 4 first?

Answer 1

When the parking brake is set, the first hydraulic system pressurized may supply a small amount of fluid to the brake lines. When brakes are released, that small amount of fluid returns to hydraulic system 4. Pressurizing hydraulic system 4 before pressurizing the other hydraulic systems precludes the transfer of hydraulic fluid from system 1 or 2 into system 4

Question 2

Hydraulic DEMAND Pump Selector: AUTO - when do pumps operate?

all - (2)

1/4 - (2)

Answer 2

• engine pump output pressure low, or fuel control switch in CUTOFF
• trailing edge flaps, or gear in transit

Question 3

Hydraulic System (SYS) Light Illuminated (amber) - (3)

Answer 3

• low hydraulic system pressure
• low hydraulic reservoir quantity
• excessive hydraulic fluid temperature

Question 4

ENGINE Hydraulic Pump Switch ON - engine hydraulic pump pressurizes system when _____

Answer 4

engine rotates

Question 5

Demand Pump Low PRESS Light Illuminated (amber) - (2)

Answer 5

• demand pump selector positioned to OFF or AUX

* demand pump commanded to operate and output pressure is low

Question 6

The airplane has ___ independent hydraulic systems

Answer 6

4

Question 7

The hydraulic systems power : (9)

Answer 7

• primary flight controls
• flaps
• spoilers
• elevator feel
• stabilizer trim
• landing gear
• brakes
• steering
• autopilot servos