HYD System

Question 1

NATOPS Chap 2

Hydrualic System

What Components do the Hyd pumps provide Pressure to?

Answer 1

Flight controls, APU, Tail Rotor, Resucue Hoist.

Question 2

NATOPS Chap 2

Hydrualic System

The Hydraulic System Components are?

Answer 2

Three identical and interchangeable Pumps, Two transfer mods, one util mod, three dual-stage primary servos, tail rotor servos, pilot-assist servos, apu accum, and rescue hoist.

Question 3

NATOPS Chap 2

Hydrualic System

What are the only actuators that don’t operate at 3000psi?

Answer 3

Pitch and roll trim actuators

Question 4

NATOPS Chap 2

Hydrualic System

Can the systems operate idependently of each other?

Answer 4

Yes they can, but they are also redundant and supported by the electric motor-driven backup pump

Question 5

NATOPS Chap 2

Hydrualic System

What drives the #1 hyd pump?

Answer 5

The #1 access mod

Question 6

NATOPS Chap 2

Hydrualic System

What is incorporated into the Hydraulic pump?

Answer 6

a Pressure relief valve, pressure filter, bleed valve, return filter, auto low-level sensing switch

Question 7

NATOPS Chap 2

Hydrualic System

What triggers the RSV Low Caution?

Answer 7

The automatic low-level sensing switch (mounted on top of the pump)

Question 8

NATOPS Chap 2

Hydrualic System

What does the Priority Valve do?

Answer 8

It will secure Pressure to the Rescue hoist if the Backup pump is supplying pressure to the tail rotor servo

Question 9

NATOPS Chap 2

Hydrualic System

How long does it take to for the B/U pump to energize?

Answer 9

4sec on APU/ext pwr or 0.5sec with either main gen on.

Question 10

NATOPS Chap 2

Hydrualic System

On/Auto/off fx of B/U pump (WOW activated)

Answer 10

OFF- B/U pump remains off
Auto- B/U auto maintains px for #1/2 Hyd Pump and #2 TR servo
On- B/U pump recirculates hyd fluid to and from each xsfr mod and maintains Px in APU accum and rescue hoist as rq’d

Question 11

NATOPS Chap 2

Hydrualic System

What causes the Backup Pump to automatically turn on?

Answer 11

#1 HYD Pump Caution
#2 HYD PUMP Caution
#1 RES LOW Caution
#1 TR Caution

Question 12

NATOPS Chap 2

Hydrualic System

What Criteria must be met to run Hyd Leak Test? (ABWAR)

Answer 12

1) AC power
2) B/U Pump in AUTO position
3) WOW
4) All Hyd Resv Full
5) Rotors Engaged

Question 13

NATOPS Chap 2

Hydrualic System

Collective to yaw

Answer 13

Name: Collective to Yaw

Cause: Main Rotor Torque

Compensation Requirement: Nose yaws right when collective is increased

Compensation: Tail rotor thrust is increased

Question 14

NATOPS Chap 2

Hydrualic System

Collect to Lateral

Answer 14

Name: Collective to Lateral

Cause: Lateral Lead (tail rotor propeller effect)

Compensation Requirement: Helo drifts right when collective is increased.

Compensation: Rotor disc is tilted left

Question 15

NATOPS Chap 2

Hydrualic System

Collect to Long

Answer 15

Name: Collective to Longitudinal

Cause: Rotor downwash on stabilator

Compensation Requirement: Nose pitches up and helicopter drifts aft when collective is increased

Compensation: Rotor disc is tilted forward

Question 16

NATOPS Chap 2

Hydrualic System

Yaw to Long

Answer 16

Name: Yaw to Longitudinal

Cause: Tail Rotor lift vector

Compensation Requirement: Nose pitches down and helicopter drifts forward when left pedal is applied.

Compensation: Rotor disc is tiled aft

Question 17

NATOPS Chap 2

Hydrualic System

Collect/airspeed to yaw

Answer 17

Name: Collective/Airspeed to Yaw

Cause: Camber of tail rotor pylon varies side load with airspeed

Compensation Requirement: Nose yaws left as airspeed increases

Compensation: A portion of the main rotor torque compensation is provided by a trim input that is proportional to collective position and airspeed. The trim input is then progressively washed out as pylon side loads increase with airspeed.

Question 18

NATOPS Chap 2

Hydrualic System

What is the job of the Transfer Module?

Answer 18

It automatically routes hydraulic fluid from the backup pump if No. 1/2 Hydraulic system pressure is lost.

Question 19

NATOPS Chap 2

Hydrualic System

What are the components in the #1 Transfer Module

Answer 19

It consists of:
a transfer/shuttle valve,
pressure switch,
first-stage primary servo shutoff valve,
and first-stage tail rotor servo shutoff valve.

*The #2 is the identical except it incorportates the second stage Primary servos

Question 20

NATOPS Chap 2

Hydrualic System

What happens if No. 1 Hydraulic pressure is lost?

Answer 20

The transfer/shuttle valve routes backup pump hydraulic fluid to the first stage of the primary servos and the first stage of the tail rotor servo. The pressure switch illuminates the #1 HYD PUMP caution and sends a signal to the LDI when No. 1 hydraulic pump pressure drops below prescribed limits.

Question 21

NATOPS Chap 2

Hydrualic System

What causes the PRI SERVO PRESS caution?

Answer 21

When at least one of the three pressure switches on the first or second stage of the primary servos sense low hydraulic pressure, a circuit is completed that actuates the #1/#2 PRI SERVO PRESS caution

Question 22

NATOPS Chap 2

Hydrualic System

What switches and valves are on the Transfer Module, and what are the associated cautions/advisories?

Answer 22

1) Pressure Switch- #1/#2 HYD PUMP
2) Transfer Valve- no associated caution/advisory

3) Shutoff Valves-
a) 1st stage Pri servo shutoff valve
b) 1st stage Tail Rotor shutoff valve
c) Pilot assist servo assembly shutoff valve
d) 2nd stage Pri servo shutoff valve