FLIGHT CONTROLS

Question 1

To which PCUs is the First Officer’s control wheel connected?

Answer 1

It is connected by cables to the spoiler PCUs through the spoiler mixer.

(FCOM 9.20.3)

Question 2

To which PCUs is the Captain’s control wheel connected?

Answer 2

It is connected by cables to the aileron PCUs through the aileron feel and centering unit.

(FCOM 9.20.3)

Question 3

During takeoff, from which speed becomes the rudder aerodynamically effective?

Answer 3

Between 40 and 60 knots.

(FCOM 9.20.2)

Question 4

With which flight controls do we roll the aircraft?

Answer 4

2 ailerons and 8 flight spoilers

(FCOM 9.20.2)

Question 5

The primary flight controls are powered by redundant hydraulic sources; system A and system B.
If we loose 1 system, can we still control the aircraft?

Answer 5

Either A or B system can power all flight controls with no decrease in airplane controllability.

(FCOM 13.10.1)

Question 6

With what are the control wheel, column and pedals linked?

Answer 6

They are linked mechanically to hydraulic PCUs which command the primary flight surfaces: ailerons, elevators and rudder.

(FCOM 9.20.1)

Question 7

If we loose hydraulic systems A and B, which flight controls can be operated?

Answer 7

The ailerons and elevators may be operated manually, control forces are higher due to friction and aerodynamic loads.
The rudder may be operated by the standby hydraulic system.

(FCOM 9.20.1 and 9.20.3)

Question 8

If the captain’s control wheel is connected to the aileron PCUs through the aileron feel and centering unit AND the first officer’s control wheel is connect with the flight spoilers PCUs through the spoiler mixer, how come BOTH aileron and spoilers move when we only turn 1 control wheel?

Answer 8

Because the control wheels are connected by a cable drive system which allows actuation of both ailerons and spoilers by either control wheel. This allows the pilots to bypass a jammed control or surface.

(FCOM 9.20.1)

Question 9

Explain: Aileron Transfer Mechanism.

Answer 9

If the ailerons or spoilers are jammed, force applied to the Captain’s or FO’s control wheels will identify which system, aileron or spoilers, is usable and which control wheel can provide roll control.

(FCOM 9.20.3)

Question 10

If the aileron control system get jammed, can we still roll the aircraft?

Answer 10

Yes, through the FO’s control wheel as this is connected with the spoiler system. The captain’s control WHEEL will be inoperative. This is called the aileron Transfer Mechanism.

(FCOM 9.20.3)

Question 11

If the spoiler system get jammed, can we still roll the aircraft?

Answer 11

Yes, with control wheel of the captain as this is connected with the aileron system. The control WHEEL of the FO will be inoperative. This is called the Aileron Transfer Mechanism.

(FCOM 9.20.3)

Question 12

Are the rudder pedals connected with each other?

Answer 12

Yes, there is a rigid (stijf) connection between both pairs.

(FCOM 9.20.1)

Question 13

What will happen when we switch the FLT CONTROL A switch to STBY RUD?

Answer 13

Activates standby hydraulic system pump and opens standby rudder shutoff valve to pressurise standby rudder Power Control Unit.

(FCOM 9.10.1)

Question 14

What will happen when we switch the FLT CONTROL A switch to OFF?

Answer 14

Closes flight control shutoff valve isolating ailerons, elevator and rudder from associated hydraulic system pressure.

(FCOM 9.10.1)

Question 15

What happens when we push the AILERON trim switches?

Answer 15

The trim electrically repositions the aileron feel and centering unit, which causes the control wheel to rotate and redefines the aileron neutral position.

(FCOM 9.20.3)

Question 16

What is the function of the spoiler mixer?

Answer 16

Controls the hydraulic Power Control Units on each spoiler panel to provide spoiler movement proportional to aileron movement.

(FCOM 9.20.4)

Question 17

What do the flight spoilers do on the wing with up aileron and what do the flight spoilers do on the wing with down aileron?

Answer 17

The flight spoilers rise on the wing with up aileron and remain faired on the wing with down aileron.

(FCOM 9.20.4)

Question 18

What can we do in case of a control column jam?

Answer 18

Applying force against the jam will breakout either the Captain’s or First Officer’s control column.

(FCOM 9.20.6)

Question 19

Explain Elevator Feel System

Answer 19

The elevator feel computer provides simulated aerodynamic forces using airspeed (from the elevator pitot system) and stabiliser position. Feel is transmitted to the control columns by the elevator feel and centering unit.

(FCOM 9.20.6)

Question 20

Explain Mach trim system.

Answer 20

This system provides speed stability at speeds above Mach .615 by adjusting the ELEVATORS with respect to the stabilizer as speed increases.

(FCOM 9.20.7)

Question 21

How can we control the horizontal stabilizer?

Answer 21

A single electric trim motor is controlled through either the stab trim switches on the control wheel or autopilot trim. The stabilizer also can be positioned manually rotating the trim wheel.

(FCOM 9.20.7)

Question 22

Explain the purpose of the Speed Trim System. (STS)

Answer 22

To return the airplane to a trimmed speed by commanding the stabilizer in a direction opposite the speed change.

(FCOM 9.20.8)