Flight Controls

Question 1

Pre tilt of the
rotors

Answer 1

FWD transmission tilted 9 degrees forward and aft is tiled 4 degrees forward which aid in ground taxiing.

Question 2

Longitudinal Cyclic Trim
(LCTs)

Answer 2

Electrical actuators attached to the swashplates which program the tilt of the rotor disks. AS airspeed increases forward tilt increases to minimize fuselage pitch and attitude changes.

This reduces blade flapping and stress on the aft vertical shaft.

Question 3

Differential collective pitch

Answer 3

Varies the amount of thrust produced by the forward and aft rotor system, creating pitch attitude changes.

Forward cyclic decreases collective pitch (thrust) in the forward rotor and increases thrust in the aft.

Question 4

Yaw directional
control

Answer 4

Rotors tilt equally in opposite
directions.

Question 5

Lateral control

Answer 5

Both rotor systems tilt the same way

Question 6

First stage mixing
unit

Answer 6

Mixing units combine all control inputs into one integrated output to the upper boost actuators which move the swashplates.

Section 1 mixes the pitch and thrust.

Section two mixes the roll and yaw.

Question 7

Cockpit controls

Answer 7

Cockpit control movements are transferred through mechanical linkage to the transfer bell cranks
and vertical controls in the flight controls closet.

Question 8

Viscous damper

(Pallet at STA 95
Thrust and YAW)

Answer 8

Improves control feel by reducing control sensitivity

Question 9

Thrust Control Position Transducer (CPT)

(Pallet at STA 95 Thrust and YAW)

Answer 9

Signal sent to the Electronic Control Unit (ECU) Maintains a constant rotor rpm as thrust is changed.

Question 10

Thrust Cockpit Control Driver Actuator (CCDA)

(Pallet at STA 95 Thrust and YAW)

Answer 10

Includes the thrust brake. Takes 7 to 23 lbs. of force to slip the brake.

The Driver actuator actually can move the thrust up and down

Question 11

YAW control position
transducer (CPT)

(Pallet at STA 95
Thrust and YAW)

Answer 11

Produces a position signal and sends to DAFCS via the Flight Control Computer

Question 12

Pitch CCDA

(Pallet at STA 120
Pitch and Roll)

Answer 12

Contains magnetic brake and driver actuator. Controlled by the DAFCS trim switch on the cyclic and will physically move the cyclic fore and aft.

Question 13

Integrated Lower Control Actuators

(Pallet at STA 120 Pitch and Roll)

Answer 13

One for each axis and operate on 1500 PSI hydraulic pressure to provide cockpit control boost.

They also provide DAFCS augmentation in the pitch, roll, and yaw thanks to the extensible links.

Pressure reduced via the two lower pressure control modules (1 for No 1 flight hydraulics, 1 for No 2)

Question 14

Boost Actuators

(Pallet at STA 120
Pitch and Roll)

Answer 14

Each ILCA has two independent boost actuators which provide hydraulic assistance for cockpit
control inputs and prevent control feedback.

Question 15

Extensible Link

Answer 15

YAW, Roll, and pitch have an
extensible link and they provide a means for the Flight Control Computers (FCCs) to make inputs into the pitch, roll, and yaw axes without the pilot feeling the control inputs.

Question 16

Linear Variable Position
Transducer

Answer 16

The tiny link that sends a signal proportional to the extensible link position to the FCC.

Question 17

Differential Airspeed Hold
(DASH) actuator

Answer 17

Provides pitch attitude stabilization (below 40 KCAS), airspeed stabilization (above 40KCAS), and positive stick gradient. FCCs command two actuators (one on top,
one on bottom) to extend or retract to hold an airspeed.

Question 18

Upper Boost Actuators

Answer 18

Two on the forward rotor, two on the aft. Each rotor has a swiveling and a pivoting. These move the swashplate as required.

Question 19

Ground Regime
(when weight on wheel switches are activated)

Answer 19

1. Signals computers to reduce input to the pitch ILCA by 50%, reducing porpoising during 2-wheel taxi.
2. Tells FCCs to ignore the Pitch CPT (which usually programs the DASH)
3. When Both WOW switches engaged:
   - Signals DAFCS computer to drive LCTs to GND
   - Thrust CCDA stops moving the thrust (if alt hold is on)
4. Disengages TRC and PH
5. Disengages heading hold when swivel switch is in steer

Question 20

Low Speed Regime

Answer 20

1. When A/C has not accelerated past 20 KGS or has decelerated below 16 KGS.
2. Two velocity stabilization modes, TRC and PH.

• TRC provides longitudinal and lateral groundspeed proportional to cyclic stick
  displacement. It engages between 0 and 9 KGS and accelerations are less than 1 ft/s and a/c pitch and toll rates are less than 5 degrees/sec and CD REL is not pressed.
  DAFCS trim switch changes GS by 1 not per beep.
• PH holds a fixed position over the ground. Engages when A/C GS is less than 1 knot. Trim switch moves by 1 foot increments.

3. Attitude Command/Attitude stability (ACAS) – pitch and roll attitude changes proportional
   to the cyclic displacement

Question 21

Forward Flight Regime

Answer 21

1. Above 20 KGS
2. Stability about all axes
3. Bank Angle Stabilization
4. Heading Stabilization
5. Airspeed Stabilization
6. Pitch Attitude Stabilization
7. Positive Stick Gradient
8. Turn Coordination
9. Altitude Hold
10. DAFCS Trim
11. Longitudinal Cyclic Trim (LCT) System