Hydraulic Systems

What makes up the VMS?

Hydraulic systems and FCS

What pressure do the HYD pumps produce?

5,000 psi

What provides pressure to the left swashplate actuators?

HYD 2/1

What provides pressure to the right swashplate actuators?

HYD 1/2

From L to R what provides pressure to the flaperon actuators?

3, 2 ,1, 2, 2, 1, 1, 3

What provides pressure to the left rudder actuator?

HYD 1

What provides pressure to the right rudder actuator?

HYD 2

What provides pressure to the elevator actuators?

1,3,2

What provides pressure to the left conversion actuator? (from L to R)

2, 1

What provides pressure to the right conversion actuator? (from L to R)

1, 2

What utility systems does HYD 3 provide pressure for?

Cargo ramp and door actuators

Rotor positioning unit (RPU)

Engine start system

Wing stow system

Cargo winch

Rotor brake

EAPS blowers

Wheel brakes

Landing gear actuators

Aerial refueling retractable probe (ARRP)

Nose wheel steering

Purpose of electro-hydraulic actuators?

To extend, retract, and position the flight control surfaces

How many swashplate actuators are there?

6

How many flaperon actuators are there?

8

How many conversion actuators are there?

2

How many elevator actuators are there?

3

How many rudder actuators are there?

2

Where is HYD 1 pump located?

Left TAGB

Where is HYD 2 pump located?

Right TAGB

What monitors pressures and fluid levels for the automatic leak detection and isolation system?

FCCs

What type of pump are the HYD pumps?

Constant-pressure, variable-displacement, piston-type pump

Flow rate of HYD1/2 in VTOL (100% Nr)?

38 gpm

Flow rate of HYD1/2 in APLN (84% Nr)?

32 gpm

What is displayed at the bottom of the FCS Status Layer in regards to each hydraulic system?

Pressure (psi), temp (deg C), fluid quantity (in cu)

Where are the nacelle heat exchangers located?

Aft section of each nacelle

What does the nacelle heat exchanger provide cooled oil for?

HYD, TAGB/generator, PRGB

Where does the nacelle heat exchanger exhaust its air?

IR suppressor

What pulls air into the nacelle heat exchanger?

TAGB driven nacelle blower

Where are the HYD1/2 flight control modules located?

Adjacent to respective systems pumps

What maintains optimal HYD fluid temperature?

Temperature transducer and thermal control valve

When is a caution posted for HYD1 or HYD2 high temp caution?

121 deg C

HYD1/2 reservoir capacity

330 cu in

What monitors reservoir fluid levels?

2 LVDTs attached to the reservoir piston

Normal system pressures?

4600 to <5250 psi

What is the capacity of the nitrogen-pressurized accumulator?

12 cu in

What does the accumulator do?

Provides pressure to the reservoir to ensure positive pump suction pressure during startup and shutdown to prevent pump cavitation

When does the relief valve open?

5850 psi

What does the fluid compensation valve do?

Shuttles additional fluid gained during ground checkout valve actuation by HYD1 and HYD2 back into HYD3

What pressurized HYD1/2 prior to pumps operating during ground ops to engine start and after engine shutdown?

HYD3

When do HYD1/2 pumps pressurize their respective systems?

58% Nr

What do thermal control valves do?

Rapidily warm up HYD fluid when fluid temp is below 4 deg C

Where is the HYD1 thermal control valve located?

Right wing

Where is the HYD2 thermal control valve located?

Left wing

Where is HYD1 local switching/isolation valve?

Left nacelle

Where is HYD2 local switching/isolation valve?

Right nacelle

What does the isolation valve do?

Prevent HYD fluid from flowing outside the local wing nacelle when a leak is detected

What does the switching valve do?

Transfer HYD power from HYD1 or HYD2 to the HYD3 system to power the swashplate actuators

What does the ground checkout valve do?

Allow HYD 3 to power all of the hydraulically actuated aircraft components for ground ops when the proprotors aren’t turning and the APU is operating

Where are remote switching valves located?

Under each TAGB

Where is HYD1 remote switching valve located?

Right nacelle

Where is HYD2 remote switching valve located?

Left nacelle

During normal ops what do the remote switching valves do?

Allow for HYD1 fluid to pass to the swashplate actuators in the right nacelle and vice versa

During ground checkout ops what do the remote switch valves do?

Allow HYD3 to power HYD1/2

In the event of a HYD1 or HYD2 malfunction what do the remote switch valves do?

Direct HYD3 pressure to the B/U HPDUs to power conversion actuators

When a HYD3 leak is detected what do the remote switch valves do?

Transfer swashplate actuator pressure from isolated HYD1 or HYD2 system

What allows for continuous, uninterrupted flow of hydraulic fluid to hydraulic components during nacelle and wing movement?

Swivel fittings and flexible hoses

Where can you check the reservoir fluid level for all 3 systems?

HFLM

Where is HYD3 pump located?

MWGB

When is HYD3 pump operational?

Proprotors are turning and driving the MWGB or when the APU is operating and clutched to the MWGB

HYD3 reservoir capacity

660 cu in

What does the solenoid operated valve do?

3 way, 2 position, shut-off valve that shuts off HYD pressure to HYD3

What does the MWGB oil cooler and fan assembly provided cooled oil for?

MWGB/CFG1

HYD3

VFG4

SDC

Where are HYD3 thermal control valves located?

One in each nacelle between the TAGB and engine

What does the utility isolation valve do?

Controls pressure to a number of the utility subsystems

What position is the utility isolation valve in flight and the gear are up and locked?

Closed

When is UTIL OPEN/CLOSE unavailable?

HYD3 failed

HYD3 manually selected OFF

HYD3 energized UIV due to a leak and is backing up swashplate actuators and the HYD3 reservoir is less than 150 cu in

WOW active

In APLN mode what is the range of the flaperons?

25 deg up and 40 deg down

Where are the flaperons usually located in VTOL mode?

73 deg down (FULL)

Maximum elevator deflection

30 deg up and 20 deg down

Maximum rudder deflection

20 deg L and 20 deg R

What are the swashplate actuators connected to?

Non rotating swashplate

What type of actuator are the swashplate actuators?

Dual-tandem, jam-proof

What occurs when hydraulic fluid is lost to half of the swashplate actuators?

The actuator will still perform at a reduced rate within the operational envelope

Where are the conversion actuators located?

Outboard end of each wing

What are the conversion actuators connected to?

Nacelle and wing

How many HPDUs does each conversion actuator have?

3

What are HPDU1/2 powered by?

HYD1/2

If HPDU1/2 fails what drives the ball screw?

HPDU3

When the nacelles are driven by the HPDUs what can the nacelles not be rotated below with WOW or cabin doors open?

45 deg

What utility systems pressurized by HYD3 are independent of the UIV?

EAPS blowers

Engine start system

Rotor brake

RPU

Landing gear actuators

What do EAPS blowers do?

Ensure relatively clean flow of air into the engine

What provides the operating pressure for each engine start motor?

HYD3

When the ECL is in the CRANK or START position what happens?

Energizing EAPS/start control valve allowing for HYD 3 fluid to pass through the starter and rotate the engine internal gas generator

Where is the rotor brake mounted?

Forward section of MWGB

Designed stop times of rotor brake

12 s at 40% Nr

20 s at 100% Nr

When the rotor brake is ON where are ECLs blocked?

Movement past CRANK

Where must the ECLs be for the rotor brake to be able to be applied?

OFF

What does the RPU do?

Indexes, rotates, and locks the proprotors during BFWS ops

What subsystems required the UIV to be open to operate?

Wing stow system

Wheel brake system

Nose wheel steering

Cargo Winch

Cargo ramp and door actuators

ARRP

What pressure is provided to the brake master cylinders?

HYD3 fluid reduced from 5000 to 2000 psi

What is capacity of the cargo winch?

2000 lb

How much cable does the cargo winch have?

150 ft

What is the end of cable warning on the cargo winch?

First and last 20 ft are painted orange

How fast can you open/close the cargo ramp?

12 s

How many cargo ramp actuators are there?

2

Max speed with ramp open

260 KCAS

Maximum ramp loading

1750 lbs

Maximum palletized load on ramp for ground ops movement

5000 lbs

When do the FCCs energize the ground checkout valves inside HYD1/2 local switching/isolation valve modules?

APU operating and HYD3 pressure reaches 4000 psi

What happens when the FCS detects an imminent overtilt condition?

HYD1/2 FAIL, HYD1/3 FAIL, HYD2/3 FAIL, and all HYD systems will be shutdown