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
How long does it take to close the main inboard gear doors using the emergency nitrogen system?
3 seconds
What is the landing gear limiting speed?
200 KIAS
What is the emergency landing gear extention speed?
150 KIAS
What are the limits for the nitrogen storage bottle?
1350-1650 psi
What is the normal strut extension for the nose gear?
3.5 inches
What is the minimum strut extension for the main gear?
1.1 inches
During normal operation, the T-1A landing gear are _________ controlled and _____ operated.
electrically controlled and hydraulically operated
Where is the landing gear HORN CUT button (used to silence the landing gear warning tone) located?
on the outboard grip of both control yokes
What is used to raise the landing gear if the landing gear downlock release level fails to release in flight?
Downlock release button
When turning the aircraft on the ground, you can cause the nose wheel to caster beyond 25 degress (up to _____ deg) by applying rudder, differential power, and differential braking.
45 degrees
During the gear extension sequence, when does the main landing gear lower?
After the inboard gear doors are fully open
How are the uplock assembles released during emergency gear extension?
Mechanically
What is the maximum allowable altitude for inflight gear extension?
20000 feet MSL
What must be true for the anti-skid system to operate?
The power brake system must be functional and the anti-skid control switch must be in the ON position
What does a transducer do?
Electrically sense a change in wheel rotation speed and provides data to anti-skid control box
Locked wheel protection is available above what tire speed?
14 knots
What three positions does the anti-skid control switch have?
ON, OFF, TEST
At what temperature will the thermal fuse plugs located in the wheels soften and blow out?
430 deg F
At what brake energy will the thermal fuse plus blow out?
8.1 million ft-lbs
When should you assume you have hot brakes?
Any braking effort between 8.1 and 14.8 million foot-lbs
How long does it take for the max temperature to reach the outer surface?
15 minutes
What is the purpose of the brake accumulator?
Dampen pressure fluctuations from the hydraulic system
Which component of the brake system permits braking from either pilot position?
Mixing valves
If normal hydraulic pressure is not available to the power brake anti-skid control valve, the brake system automatically reverts to what mode?
Manual
Parking brakes prevent aircraft movement by what?
Trapping hydraulic pressure
When does the ANTISKID FAIL light illuminate?
Landing gear extended, anti-skid control switch ON, and loss of electrical power to the anti-skid control valve or the control box
gear is extended and anti-skid control switch is in the OFF position
dump command is received for an extended period of time
The amount of energy absorbed when stopping the T-1A is a factor of what variable?
Ambient temperature, pressure alititude, aircraft weight, speed at which brakes are applied, headwind/tailwind componenet
When will brake damage and failure occur?
14.8 million ft-lbs of brake energy are absorbed
What are the indications of hydraulic pump pressure low?
L or R H PMP PRESS LO annunciator illuminates along with MASTER CAUTION RESET (hydraulic pressure on gauge should be normal)
What are the indications of high hydraulic pressure?
the only indication is on the hydraulic gauge iteself
What does moving the hydraulic pressure bypass switch to the REL position do?
Opens the bypass valve, diverting all hydraulic fluid back to the reservoir and dumping system pressure and essentially forcing hydraulic system failure
What are the indications of low hydraulic pressure?
Pressure gauge reads below 1350 psi, possibly H PMP PRESS LO and HYD LEVEL LO
If all hydraulic pressure is lost, which systems will you lose?
Normal gear extension, flaps( if extended, they will remain in that position), speed brake (if extended, will blow down), power brakes and antiskid
In the event of loss of total hydraulic pressure, what should you do?
Emergency gear extension, no-flap landing, expect landing distance to increase 90% over computed 30-flap landing distance, consider reducing ross weight to lower approach and landing speeds
If a tire failure occurs prior to S1, should you abort the T/O?
Yes
If you a tire failure occurs after T/O what should you do?
Do not change configuration
What is the maximum rudder deflection?
30 degrees each side)
What is the max elevator deflection?
12 degrees down, 25 degrees up
How does the aft flap move?
mechanical linkage
What is the max airspeed to extend the flaps past 10 deg?
170 KIAS
What is the max airspeed to fly with the flaps past 10 deg?
165 KIAS
What is the max airspeed to extend the flaps to 10 deg?
200 kias
What is the max airspeed to fly with the flaps at 10 deg?
200 kias
G limits with flaps up?
-1.0 to 3.2 G’s
G limits with flaps extended?
0 to 2.0 G’s
What conditions must be met for the speed brakes to extend?
both throttle below NORM T.O position, flaps not extended beyond 10 degrees
