Systems - HYD/Gear/Brakes Flashcards
What type of Hydraulic Fluid do we use? What color is it?
Skydrol, purple in color.
What is a core principle regarding compressibilty of Hydraulic Fluid
Must be non-compressible.
What are the two main principles of an accumulator?
1) Works as a shock absorber
2) Stores energy which is used when the system pressure decreases.
How many Hydraulic Systems do we have on the EMB-145? How many pumps per system?
2 systems, and 2 pumps per system (1 engine driven and 1 electric).
What is the normal system pressure for the Engine Driven Pump? For the Electric Pump?
1) Eng Driven - 3000 psi
2) Electric - 2900 psi
When will the electric pump turn on automatically?
When in the AUTO position and:
1) Associated Engine drops below 56.4% N2 (Eng Fail)
2) When system pressure drops below 1600 psi.
What is the biggest difference between the Eng. Driven pump and electric pump?
Volume, the Eng driven pump is capable of putting out 10 times the volume of the electric pump.
Where is the Engine Driven Hydraulic Shutoff located? How do you close the valve?
1) Located FWD of the engine driven pump
2) Two ways to close
- Pull Fire Handle
- Eng Pump Shutoff button
Where is the Hydraulic Mule (Cart) Service Point?
External Power Supply which is located on their respective side in the fuselage at the trailing edge of the wing root.
What components does the HYD 1 system supply
Brakes (outboard)
Rudder
Ailerons (Both sides)
Thrust Reversers (on side)
Spoilers (Inboard)
Steering (Nose Wheel)
Landing Gear
What components does the HYD 2 system supply?
Brakes (Inboard)
Rudder
Ailerons (Both Sides)
Thrust Reverser (On Side)
Spoilers (Outboard)
Brake (Emergency/ Parking)
What does the term Mechanical Reversion refer to with respect to the Hydraulic System. What sytems will Mechanically Revert?
1) If the HYD system fails, the systems (Rudder and Aileron) will revert to mechanical operation (Cables)
How do you bring the gear down in the event of the HYD system failure?
Free Fall - use Landing Gear Freefall handle.
What system(s) is on the No 1 Acumulator?
The landing gear.
What system(s) is on the No 2 Acumulator?
Parking/ Emergency Brake
How many applications does the No2 accumulator have on the emergency brake? How long is the hold time?
1) 6 applications
2) 24 hours of hold
What indication will you get in the cockpit when the Parking Brake is set. How many lbs of pressure will activate the Parking Brake
“Brake On” light will come on.
149 lbs of pressure will activate it.
What does the Priority Valve do?
Prioritizes flight controls over landing gear by restricting flow of fluid to the gear when operating the landing gear on the electric Hyd Pump.
What system is the Priority Valve on. Give an example of when it will prioritize?
Only on system 1 and will prioritize when you have a #1 engine failure on Takeoff
What kind of pump is the engine driven pump, what capability does it have with respect to variation of fluid flow?
Piston driven pump that varies the amount of fluid flow based on required draw.
What kind of pump is the electric pump? What are its limitations
Impeller pump with one flow setting (does not vary based on draw) and can’t keep up with high loads (ie. gear retraction).
Where is the FWD Hydraulic accumulator located and what system does it supply?
Right side FWD near the FO window. Supplies the No 1 system.
How is the Landing Gear Normally commanded and operated
Electrically commanded and HYD operated.
What are the three main principles of the Landing Gear System?
1) The only thing held under constant HYD pressure are the Nose gear doors.
2) Gear is held up by J. Hooks
3) Gear is held down by big ass springs & over center locks.
What are the three ways to get the Landing Gear Down?
1) NORMAL - Gear Handle
2) Electronic Override switch (Near FO leg)
3) Mechanical Freefall lever (Near FO leg)
If you pull the Freefall Lever, what does the system do with the HYD pressure already in the lines?
Routes all the pressure to the return to avoid a hydraulic block.
How is Air/Ground indication determined?
5 Weight on Wheels proximity switches.
Where is the nose gear proximity switch signal sent?
Only to the nosewheel steering and Thrust reverser logic.
What is the majority rules concept with regard to the the 4 remianing proximity switches?
- If one signal is invalid, the remaining 3 will be processed with at least 2 indicating the same status
- If two are invalid, the two remaining will be processed ONLY if they send the same signal.
- If disagreement between the two, it goes to the fail safe for the associated system (ie. Gear Down).
Where can you find backup System information (Including Landing Gear Information)
RMU.
Other than an impending Gear up landing, when should the Landing Gear Warning horn be going off?
If the gear is up and Radio Alt. is Inop or too high to detect the ground.
On what occassion should you silence the Landing Gear Warning Horn?
If you are in flaps 0°-9° and above 1200 ft AGL with the R.A inop.
In what position should the gear be if you are below 1200’ AGL and Flaps 22
DOWN
How is the Gear Handle Down Lock Release operated
Mechanically releases the lever lock.
In what scenario would you manually release the lever lock if the landing gear handle does not come up for normal retraction?
On takeoff, after V1 Eng Failure so that you can maintain an acceptable climb rate to clear obsticles.
How should the taxi lights be oriented (check during pre-flight)
- Clear lens should be on top for horizontal distance
- Corrugated lens on the bottom for periphiral distance.
How are the brakes operated on the EMB-145
Brake by wire - Electrically commanded and hydraulicaly operated.
Which HYD system supplies the outboard brakes? The inboard brakes?
Outboard - HYD Sys 1
Inboard - HYD Sys 2
What Bus is the Brake system on? What will kind of braking availability will you have in an electrical emergency?
Essential Bus, you will have all normal braking during an electrical emergency.
How is the Parking/ Emergency Brake operated
Mechanically applied and hydraulicly operated.
Does it make a difference to the amount of braking you will get from the Parking/ Emergency Brake based on the amount of force you apply?
Yes, it is proportional.
What is good technique when setting or releasing the parking brake and why?
Fully apply toe brakes. This will minimize the transfer of HYD fluid from HYD1 to HYD2.
Does the Parking/ Emergency brake have any anti skid or anti lock protection?
No
What is good technique when landing on contaminated runways with no reversers?
Stay on toe brakes, and DO NOT use parking brake and DO NOT try to go around after touchdown. If you put good data into the computer you will stop eventually.
What is good technique when landing on a dry runway with brake failure warnings on your EICAS
Use Emergency Brake to stop.
When does Anti Skid become available
at 10 kts
How does the Anti Skid system work?
It looks for a wheel turning below the average speed and when it finds it, it does a partial pressure release until that wheel catches up to the others.
When is the Anti Lock Brake System available and how does it operate?
- Available at +30 kts
- Looks for a wheel 30% slower than the others
- Does a full pressure release (0) to the associated wheel
+30-30=0
Under what conditions will Touchdown Protection activate?
Brakes will not activate on touchdown until (whichever happens first):
1) WOW +3 secs OR
2) Wheel speed of 50 kts.
How are wheels stopped from spinning after T/O and gear retraction?
1) Main gear has has automatic in flight braking
2) Nose wheels are stopped by snubbers in the nose wheel well.
What type of brakes are the aircraft equipped with? What is a good technique when operating with this type of brake?
1) Carbon Brakes
2) Brake early after touchdown when aircraft is fast and apply heavily to build up some heat to increase the effectivness of the carbon.
How is nose wheel steering operated
Steer by wire - Electrically commanded and Hydraulically Operated.
What happens to nosewheel steering if you lose HYD 1 fluid
You will lose nose wheel steering
Will you have any kind of steering if you lose HYD 1?
Yes, aerodynamic steering only.
When should the steering handwheel be used? Is there a speed limit?
Sharp turns at slow speeds only, there is no specific speed limit but must use caution.
What will happen if you dis-engage the nose wheel steering?
It will free caster and you will only have aerodynamic steering.
How is the nosewheel kept centered after retraction to prevent it from becoming mis-aligned
There is a centering cam within the Nosewheel strut.
