Hydraulics Review - Final PDF

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eHydraulics Review Question off PPTs PPT1 1) Hydraulics is typically used for the following systems: flight controls, thrust reversers, landing gear and brakes 2) The law which states that pressurized fluid in a closed container will exert equal and undiminished pressure at right angles to the walls of the container that encloses it…is known as: Pascal’s Law 3) The pressure exerted by a column of fluid in an open container is determined by: the height of the fluid (Hyrostatic Paradox) 4) Power is defined as the time-rate of doing work 5) Mechanical advantage is achieved by: having an output piston that is larger than the input piston 6) What force is required at the small piston to support the 250 lbs on the large piston? Small piston: 2 sq in large: 10 sq in, 25psi total 50lbs

PPT 2 1)What is NOT considered a component in a simple closed hydraulic system? What is? Reverse flow indicator NOT Reservoir, Pump, Actuator IS 2)Which component is responsible for dampening hydraulic surges and storing energy in a hydraulic circuit? Accumulator A&P AF: 8-8 to 8-15 3) What is the disadvantage of using an open-centre hydraulic system opposed to a closed center? Only one system at a time can be effectively operated. Cannot have multiple pressures throughout. 4) A hydraulic power pack system is a self-contained system that is commonly used for: light twin-engine aircraft small, simple hydraulic systems A&P AF: 8-15 to 8-18 PPT 3a 1)What is NOT a way of pressurizing a hydraulic reservoir? What is? Pneumatic pump NOT Engine bleed air, aspirator, system pressure IS 2) A hydraulic reservoir can be pressurized using hydraulic system pressure by:

A&P AF: 8-1 to 8-5 A&P GT: 2-25 to 2-28 2-7/8 7) What is NOT a consideration for selecting hydraulic fluid? What is?

using different sized pistons (mechanical advantage) A&P AF: 8-16 to 8-20 3)Which filter uses a pleated paper element?

Cooling capacity NOT Flashpoint, chemical stability, viscosity IS 8) The three types of hydraulic fluid are:

Micronic 2) Identify the common locations for hydraulic filters (3)

vegetable, petroleum and synthetic based 9) The primary advantage of Skydrol over other types of hydraulic fluid is its:

System pressure, return and pump case drain 3) What is the purpose of a filter bypass valve?

high resistance to fire A&P AF: 8-6 to 8-8 AC 43.13-1: 9-13/14

Allows the system to operate with a clogged filter element A&P AF: 8-19 to 8-22 PPT 3b

1)The two primary types of hand operated hydraulic pumps are: single and double action 2) What is not a common use for hand operated hydraulic pumps? What is? Primary flight controls NOT Emergency/back up supple, manual operated systems, hydraulic sys without AC power IS 3) A hydraulic pump that consists of a spur gear driving a geared rotor is known as a: gerotor pump 4) Which hydraulic pump is most commonly used for low pressure, high volume systems? vane pump A&P AF: 8-22 to 8-27 1) What is not a source of mechanical power to drive a hydraulic pump? What is? auxiliary power unit (APU) NOT air turbine motor, hydraulic motor, engine IS 2) Ram air turbines (RAT) are powered by: the outside air stream PPT 3c 1)The two primary types of control valves used in aircraft hydraulic systems are: flow and pressure 2) A mechanically actuated valve that determines the order of events is called a: sequence valve 3) A hydraulic fuse is an automatic flow control device used to: shut off hydraulic fluid supply if a leak should occur downstream of the fuse 4) A device used to select essential or primary hydraulic system supply to a component or subsystem is called a: shuttle valve

A&P AF: 8-28 to 8-36 PPT 3d 1)The three primary types of accumulators are piston, bladder and diaphragm 2)What are considered accumulator functions? to provide backup braking, to dampen hydraulic surging, help the hydraulic pump under, peak pressure loads 3) The common name for an accumulator air valve is: shrader valve (like a car tire/bike tire valve) A&P AF: 8-36 to 8-39 4) 3 Types of linear actuators: Double-acting balanced, Single-acting, Double-acting unbalanced. 5) An actuator used to convert linear action into rotary motion is called a: rack & pinion rotary actuator A&P AF: 8-39 to 8-42 PPT 3e 1) Name 3 types of hydraulic switches Pressure, limit, position 2) A switch used to compare the difference in pressure from two sources is called a differential pressure switch 3) A device used to display hydraulic system pressure in the flight deck is called a: pressure transducer 4) A primary purpose of a hydraulic damper is to: Reduce flight control surface flutter at high speeds 5)What is not used for cooling hydraulic fluid? What is? Engine oil and water are NOT, Air and Fuel ARE PPT 3f 1) What are the functions of a hydraulic seal?

Minimize internal leaks and loss of pressure, Reduce wear on moving components, Prevent contamination from entering the system. 2)The most common type of integral seal in an aircraft hydraulic system is the:

RAT (ram air turbine) A&P AF: 8-46 to 8-48 PPT 5 1) What effect does the failure of one hydraulic system have on a fly-by-wire system?

o ring 3)The most effective way to determine that you are using the correct O-ring…

No adverse effect, just a lot of redundancy. 2) In high speed flight the rudder has…

Check the IPC and confirm the part number on the Oring package 4)When installing an O-ring in a hydraulic system you should always lubricate it with: with the fluid being used in the applicable system A&P AF: 8-42 to 8-46 A&P GT: 7-25 to 7-27 AC 43.13: 9-20 PPT 3f 1) A roller type tube cutter is primarily used for… Softer metal lines 2) The most common flare angle for a/c rigid tubing is… 37’ (35’ old fashioned) 3) Minimum amount of bends a rigid tube requires? One minimum (for rigidity) 4) The size of a flex line is determined by… Inside diameter 5) Simple method to check that a flex line isn’t twisted? Reference the lay line A&P GT: 10-1 to 10-20 AC 43.13: 9-18 to 9-26 PPT 4 1)The piper apache shuttle valves are used to: Select hydraulic or CO2 bottle pressure for gear operation 2) Which of the following unit is used to provide backup hydraulic pressure if all other systems should fail?

Reduced travel authority Transport Category Aircraft Systems 5-1 to 5-19 PPT 6 1) The first and most important procedure to follow before cracking a hydraulic line is: Lock out and safety the system (C/Bs and warning tags) AC 43-13: 9-15 to 9-18 LANDING GEAR Intro review questions: 1) A “conventional” landing gear consists of: A tail wheel and two main gear (“tail dragger”) Other set ups... Tricycle and Tandem (wheels support wings) PPT 2 – Design 1)What is the component that accommodates the gear pin? Down lock linkage 2)What is a common practice when towing an aircraft? Disconnect the nose gear scissors (they keep wheels aligned) Note: Small a/c: Fixed or retractable landing gear (partially or fully) Large a/c: Fully retractable, components:  cylinder assembly,  side strut (upper&lower),  drag strut(upper&lower),  Down lock linkage,  lock actuators and springs (for downlock linkage),  retract actuator. Set up:  Bogey/Truck – pitch actuator adjusts for entering wheel well,

Nose gear usually has steering off rudder pedals, also has a shimmy damper  Tail wheel – steering inputs from rudder pedals generally,  Tail skid – designed with shock absorber PPT 3a - Principles 1)An aircraft oleo strut is normally serviced with:



MIL-H-5606 hydraulic fluid and nitrogen 2)When towing an aircraft with oleo struts, the nose gear scissors should be disconnected and...? The piston should be exposed, but only to a point where the nose gear centring cams are not engaged (centering cams center wheels for retraction from full extension) PPT 3b - Maintenance 1)To service an oleo... always reference the applicable maintenance manual as the first step PPT 4 - Retraction 1)What is the purpose of the baulk on the landing gear lever? Prevent “gear up” selection with WOW 2) What must be accomplished after a main gear actuator change? A gear retraction test is required. PPT 5 – wheels Note: key words Bead seat area – must critical area – high tensile loads Split hub: inboard half holds bearings and brake Flange type: single hub with removable flange **go over maintenance from lab and PPT** 1) Two common types of a/c wheels? Split hub and flange type 2) What must be accomplished before loosening the axle nut? Deflate the tire PPT 6 – tires, floats and skis PPT 7 – brakes PPT 8 – anti skid PPT 9 – steering...