Hydraulics Flashcards
What systems does the hydraulic system provide hydraulic pressure to?
Landing gear, flaps, speed brake, power brakes
How is the landing gear system controlled and operated?
electrically controlled, hydraulically operated
What are the primary flight controls?
Rudder, elevator, spoilers
What are the secondary flight controls?
Speed brakes, flaps, trim system
What does lowering the landing gear handle do?
Sends an electrical signal to initiate gear extension
Where are the brake pedals located?
The upper portion of both the pilot’s and copilot’s rudder pedals
What is used to pressurize the hydraulic reservoir?
Filtered bleed air (15 psi) from the engines
What does bleed air from the engines do for the hydraulic reservoir?
Prevents fluid from foaming and also ensures a constant supply of hydraulic fluid to the pumps
When does the HYD LEVEL LO annunciator illuminate?
When the fluid level in the reservoir drops to 0.6 gallons or less
What is normal operating pressure of the hydraulic pump
1500 psi
What drives the engine driven hydraulic pumps?
Accessory gearbox
What are the flow rates of the engine driven hydraulic pumps?
0 to 3.9 gallons per minute for each pump
When does the L or R H PRESS LO annunciator illuminate?
If pump pressure falls below 750 psi
What happens if a filter becomes clogged?
Hydraulic fluid bypasses these filters at 50 psi
When does the pressure relieve valve open automatically?
If the system pressure exceeds 1650 psi
When must the crew manually intervene by opening the bypass valve in the hydraulic system?
1850 psi
What is the normal hydraulic system range?
1350-1550 psi
When full, how much fluid does the hydraulic reservoir contain?
1.1 gallons
Where are the shutoff valves located?
Between the reservoir and pumps
What switch controls the shutoff valves?
Position switchlights on the shroud panel- L or R H/V OPEN/CLOSE
The flow of hydraulic fluid from the reservoir to a pump can be stopped by closing what valve?
Shutoff valve
The hydraulic valve package consists of valve assemblies for which three systems?
Landing gear, flaps, speed brake
The system relief valve starts to open at what psi?
1650 psi
At what pressure does the hydraulic system redline?
1850 psi
When does a red UNLOCKED gear indicator light illuminate?
- landing gear is in transit
- 1 or more gear is not down and locked
- the main gear fuselage doors are not closed and locked
When does the landing gear warning horn sound?
- Flaps are at 0- or 10-deg position and either throttle is at 70% N2 (or below)
- Flaps are extended beyond the 10-degree position (regardless of throttle position)
What is the purpose of the shimmy damper?
Installed on the nose gear and acts to dampen vibrations, especially during high-speed ground operations (like T/O and landing roll)
How are the inboard main gear doors held in position?
Mechanically
How long does gear extention/retraction take?
approximately 7 seconds
How long does the emergency gear extention take?
30 seconds