FLIGHT CONTROLS AND HYDRAULIC SYSTEM

Question 1

The UH-60 flight controls system consists of the

_____, _____, _____ subsystems.

Answer 1

lateral, longitudinal, collective pitch,

and directional control subsystems.

Question 2

Control inputs are transferred from the cockpit to the rotor blades by ______ _____ and assisted by _____ _____.

Answer 2

mechanical** **linkages** and assisted by **hydraulic** **servos.

Question 3

Pilot control is enhanced by a ____ ____ system (_ _ S),

a ____ ____ system (_ _ S), and an ____ ____ system.

Answer 3

stability augmentation system (SAS),

a flight path stabilization system (FPS),

and an electromechanical trim system.

Question 4

Dual cockpit controls consist of the ____, ____, and ___ ___ pedals.

Answer 4

cyclic, collective, and tail rotor pedals.

Question 5

The pilot and copilot’s controls are routed separately to a

____ ____ for each control axis.

Answer 5

combining linkage for each control axis

Question 6

Output from the cockpit controls is carried by ____ ____, through pilot assist ____, to the ____ unit.

Answer 6

mechanical linkage,

through pilot assist servos,

to the mixing unit.

Question 7

The mixing unit provides ____ inputs, through ____ linkages, to the ___ and ___ rotor controls.

Answer 7

proportional inputs,

through mechanical linkages,

to the main and tail rotor controls.

Question 8

The collective control system provides

_____ helicopter control.

Answer 8

vertical helicopter control

Question 9

The primary collective servos, raise or lower the main rotor ____ , causing the pitch angle of all blades to change

_____.

Answer 9

The primary collective servos, raise or lower the main rotor swashplate, causing the pitch angle of all blades to change simultaneously.

Question 10

Boost servos are located…..

Answer 10

The boost servos are located in the hydraulic compartment forward of the mixing unit.

Question 11

Order of boost servos in the hydraulic compartment.

Answer 11

The collective boost servo is on the right-hand side, and the yaw boost servo is on the far left-hand side of the pilot assist manifold.

Question 12

Boost servos make it easier for the pilot to:

Answer 12

• move the pedals and collective stick
• prevent SAS feedback into the flight controls in the yaw and pitch channels

Question 13

This mechanical mixing unit

Answer 13

combines, sums, and couples cyclic, collective, and yaw inputs.

Question 14

The _____ servos control the non-rotating swashplate, allowing the pilot to control the ____ rotor system.

Answer 14

The primary servos control the non-rotating swashplate, allowing the pilot to control the main rotor system.

Question 15

The cyclic control system provides ____, ____, and ____ control of the helicopter.

Answer 15

The cyclic control system provides forward, rearward, and lateral control of the helicopter.

Question 16

When trim is engaged, the ___, ___, and ___ trim systems are activated to maintain the position of the ___ and ___ rotor controls.

Answer 16

When trim is engaged, the pitch, roll, and yaw trim systems are activated to maintain the position of the cyclic and tail rotor controls.

Question 17

SAS servos are electrically controlled, _________ actuators, designed to provide enhanced stability in the ___, ___, and ___ axes.

Answer 17

SAS servos are electrically controlled, hydromechanical actuators, designed to provide enhanced stability in the pitch, roll, and yaw axes.

Question 18

The tail rotor (directional) control system determines the helicopter’s heading or ___ by controlling the ____ of the tail rotor blades.

Answer 18

The tail rotor (directional) control system determines the helicopter’s heading or yaw by controlling the pitch of the tail rotor blades.

Question 19

The UH-60 uses a tail rotor servo assembly, which consists of ______ independent stages

arranged in a ______ configuration for redundancy.

The assembly is mounted in the ___ gearbox.

Answer 19

The UH-60 uses a tail rotor servo assembly, which consists of two independent stages

arranged in a parallel configuration for redundancy.

The assembly is mounted in the tail gearbox.

Question 20

The first stage tail rotor servo is normally pressurized by the ___ hydraulic system.

Answer 20

The first stage tail rotor servo is normally pressurized by the #1 hydraulic system.

Question 21

In the event that a malfunction or leak occurs, the TAIL SERVO switch can be selected to ______, at which point the ____ hydraulic pump would provide pressure to operate the second stage of the tail rotor servo.

Answer 21

In the event that a malfunction or leak occurs, the TAIL SERVO switch can be selected to BACKUP, at which point the backup hydraulic pump would provide pressure to operate the second stage of the tail rotor servo.

Question 22

In the event both cables break, the ______ spring places the pilot valve in a position that provides a positive tail rotor pitch of ___° (assuming at least one tail rotor servo is pressurized).

Answer 22

In the event both cables break, this centering spring places the pilot valve in a position that provides a positive tail rotor pitch of 10.5° (assuming at least one tail rotor servo is pressurized).

Question 23

There are ___ redundant main hydraulic systems supported by _____ hydraulic pumps, and an _____ powered backup pump that can pressurize both main systems (simultaneously).

Answer 23

There are two redundant main hydraulic systems supported by separate hydraulic pumps, and an electrically powered backup pump that can pressurize both main systems (simultaneously).

Question 24

The #__ pump module supplies first stage primary servos and the first stage ____ ____ servo.

Answer 24

The #1 pump module supplies first stage primary servos and the first stage tail rotor servo.

Question 25

The #__ pump module supplies second stage primary servos and ____ ____ servos.

Answer 25

The #2 pump module supplies second stage primary servos and pilot assist servos.

Question 26

The ____ pump module supplies the ____ stage tail rotor servo, and recharges the ___.

As a contingency, it can also supply ___ or ___ stage hydraulic loads.

Answer 26

The backup pump module supplies the second stage tail rotor servo, and recharges the APU.

As a contingency, it can also supply first or second stage hydraulic loads.

Question 27

Two ______ _____ connect the hydraulic pressure outputs of the #1 and #2 pumps to the various flight control hydraulic components.

Answer 27

Two transfer modules connect the hydraulic pressure outputs of the #1 and #2 pumps to the various flight control hydraulic components.

Question 28

Both hydraulic pump transfer modules are

_____ and _____.

The two transfer module _____ are not interchangeable.

Answer 28

Both hydraulic pump transfer modules are

identical and interchangeable.

The two transfer module manifolds are not interchangeable.

Question 29

Pilot assist servos assist the pilot to overcome forces induced by the _____ system.

There are:

• three ____ servos: ___, ___, and ____
• three ___ servos
• a ___ ___ servo.

Answer 29

Pilot assist servos assist the pilot to overcome forces induced by the rotor system.

There are:

• three boost servos: collective, yaw, and pitch
• three SAS servos
• a pitch trim servo.

Question 30

The backup hydraulic system supplies pressure through the utility module to the ______ stage tail rotor servo, and it recharges the ___ accumulator following APU starts.

Answer 30

The backup hydraulic system supplies pressure through the utility module to the second stage tail rotor servo, and it recharges the APU accumulator following APU starts.

Question 31

The backup hydraulic system also supplies pressure to the #1 and #2 ______ modules to operate all servos normally supplied by the #1 and #2 ______ systems when those systems are not operational.

Answer 31

The backup hydraulic system also supplies pressure to the #1 and #2 transfer modules to operate all servos normally supplied by the #1 and #2 hydraulic systems when those systems are not operational.

Question 32

APU accumulator supplies a _____-psi hydraulic charge to the APU start motor.

Answer 32

APU accumulator supplies a 3,000-psi hydraulic charge to the APU start motor.

Question 33

Hydraulic fluid in the accumulator is used to compress a charge of _______.

Answer 33

Hydraulic fluid in the accumulator is used to compress a charge of nitrogen.

Question 34

The APU accumulator holds a nitrogen precharge of about ____ psi.

Answer 34

The APU accumulator holds a nitrogen precharge of about 1,450 psi.

Question 35

During the recharge cycle the accumulator is automatically pressurized to approximately ____ psi (± ___).

Answer 35

During the recharge cycle the accumulator is automatically pressurized to approximately 2,850 psi (± 150).

Question 36

When the accumulator nitrogen charge drops to about ____ psi, the APU ____ ___ advisory light will illuminate, and the backup pump will automatically come on.

Answer 36

When the accumulator nitrogen charge drops to about 2600 psi, the APU ACCUM LOW advisory light will illuminate, and the backup pump will automatically come on.