HSC-3 FRS > Hydraulic System > Flashcards

Hydraulic System Flashcards

(36 cards)

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1
Q

What is the purpose of the hydraulic system?

A

Provides hydraulic pressure to various hydraulic components of the flight control system, the APU system, and the rescue hoist system

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2
Q

What is the purpose of the utility hydraulic system?

A

Provides pressure for the CSTRS (Carriage, Stream, Tow, and Recovery) winch

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3
Q

What are the components of the hydraulic system?

A
  • 3 indentical and interchangable hyd pumps (No. 1, No. 2, and back-up)
  • 2 transfer modules
  • 1 utility module
  • 3 dual-stage primary servo
  • T/R servos
  • The pilot-assist servo assembly
  • The APU accumulator
  • The rescue hoist
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4
Q

What is the capacity of each hydraulic fluid reservior?

A

1 quart

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5
Q

What is the hydraulic system working pressure?

A

3000 psi (except for the pitch and roll trim actuactors in the pilot-assist servos which get 1000 psi)

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6
Q

What does the No. 1 Hydraulic System provide pressure to?

A
  • 1st Stage of the Primary servos
  • 1st Stage of the T/R servo
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7
Q

What does the No. 2 Hydraulic System provide pressure to?

A
  • 2nd Stage of the Primary servos
  • The pilot-assist servo assembly
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8
Q

When does the No. 1 & No. 2 Hydraulic Systems operate?

A

With the rotors turning

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9
Q

What drives the No. 1 and No. 2 Hyd pumps?

A

The accessory module from its respective engine

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10
Q

What does the pressure relief and bleed valves do in the hyd pump?

A

Protects the pump from high pressure in the return system

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11
Q

How many filters are in the No. 1 and No. 2 Hyd pumps?

A

There are two filters:
* Pressure filter
* Return filter

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12
Q

Which filter(s) in the hydraulic pumps has a bypass valve?

A

The return filter has a filter bypass whereas the pressure filter does not

The pressure filter does not have a filter bypass to preclude unfiltered fluid from entering the primary servos.

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13
Q

What does the automatic low-level sensing switch do?

A

It closes when it senses that the hyd fluid is low and activates the (#1/#2) RSVR LOW caution

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14
Q

What does the No. 1 Transfer Module do?

A

Routes the hydrualic fluid from the No. 1 hyd pump to the:
* 1st Stage of the primary servos
* 1st Stage of the T/R servos

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15
Q

What does the No. 2 Transfer Module do?

A

Routes the hydrualic fluid from the No. 2 hyd pump to the:
* 2nd stage of the primary servos
* pilot-assist servos

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16
Q

What does the SERVO switch do?

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A

Secures hydraulic pressure to an improperly operating primary servo stage

17
Q

How does the SERVO switch work?

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A

When it is placed into a selected position, then the associated stage servo shutoff valve is energized and closed

18
Q

In normal operations, what does the back-up hydraulic system provide pressure to?

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A
  • No. 1 and No. 2 Hyd System (when the rotors aren’t turning)
  • Rescue hoist system (back up pump is the only source of its pressure)
  • Recharges the APU accumulator
19
Q

In emergency situations, what does the back-up hydraulic system provide pressure to?

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A
  • No. 1 Hyd system
  • No. 2 Hyd system
  • 2nd Stage of the T/R servo
20
Q

How is the back-up hyd pump powered?

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A

Via an electric motor

21
Q

How does the Back-up Hydraulic Pump operate with Weight On Wheels?

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A

OFF:
* Back-up pump remains off

ON:
* Recirculates fluid and maintains pressure in the APU accumulator and rescue hoist

AUTO:
* Automatically maintains hyd pressure to the No. 1, No. 2, and 2nd Stage of the T/R servo

22
Q

How does the Back-up Hydraulic Pump operate with Weight Off Wheels?

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A

OFF or AUTO:
* Automatically maintains hyd pressure to the No. 1, No. 2, and 2nd Stage of the T/R servo
* Maintains hydraulic pressure to the 2nd Stage of the T/R servo if the TAIL SERVO switch is placed to BKUP

ON:
* Recirculates fluid and maintains pressure in the APU accumulator and rescue hoist

23
Q

When will the Leak Detection/Isolation (LDI) System automatically initiate the backup pump?

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A
  • Loss of No. 1 hyd pump pressure (#1 HYD PUMP)
  • Loss of No. 2 hyd pump pressure (#2 HYD PUMP)
  • Loss of No. 1 hyd reservoir fluid (#1 RSVR LOW)
  • Loss of pressure to 1st stage T/R servo (#1 TAIL RTR SERVO)
24
Q

What is the purpose of the utility module?

Study These Flashcards
A

To route hydraulic fluid from the backup hydraulic pump to the:
* No. 1 and No. 2 transfer modules
* 2nd Stage of the T/R servo
* Rescue hoist
* APU accumulator

25
What does the velocity fuse in the utility module do?
Secures hyd fluid flow to the APU accumulator if the flow rate exceeds a prescribed limit (1.5 gal/min)
26
What is the purpose of the LDI System?
Attempts to maintain hydraulic pressure to the primary and T/R servos by minimizing loss of hydraulic system pressure and/or fluid
27
What do the logic modules in the LDI system do?
Monitor operations of the hydraulic system via the following inputs: * Hyd pump auto low-level sensing switches * Primary servo, T/R servo, and pilot assist servo pressure switches ## Footnote **There are two logic modules.**
28
What does the hyd leak test check?
All of the circuitry except for **transfer/shuttle valve operation**
29
What criteria must be met to initiate the Hyd Leak Test?
1. AC power to the aircraft 2. BACKUP HYD PMP in AUTO 3. All hyd reservoirs full 4. Weight on wheels 5. Rotor engaged
30
What are the cautions/advisories for a **#1 and #2 HYD PUMP Failure**?
* #1 HYD PUMP * #2 HYD PUMP * #1+#2 HYD PUMP FAIL * BACK UP PUMP ON
31
What are the cautions/advisories for a **#1 PRIMARY SERVO or #1 TRANSFER MODULE LEAK**?
* #1 RSVR LOW * #1 HYD PUMP * BACK UP PUMP ON
32
What are the cautions/advisories for a **#1 T/R SERVO LEAK**?
* #1 RSVR LOW * #1 T/R SERVO * #2 T/R SERVO ON * BACK UP PUMP ON
33
What are the cautions/advisories for a **#1 T/R SERVO MALFUNCTION**?
* #1 T/R SERVO * #2 T/R SERVO ON * BACK UP PUMP ON
34
What are the cautions/advisories for a **#2 PRIMARY SERVO or #2 TRANSFER MODULE LEAK**?
* #2 RSVR LOW * #2 HYD PUMP * BACK UP PUMP ON
35
What are the cautions/advisories for a **PILOT ASSIST SERVO Leak**?
* #2 RSVR LOW * BOOST SERVO OFF * SAS * AFCS DEGRADED
36
What are the cautions/advisories for a **PILOT ASSIST SERVO malfunction**?
* BOOST SERVO OFF * SAS * AFCS DEGRADED
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