Fly-By-Wire System(FBWS)

Question 1

Primary flight controls are:

Answer 1

1. Two ailerons
2. Two elevators
3. A rudder

Question 2

Secondary flight controls are:

Answer 2

1. A horizontal stabilizer(HSTAB)
2. Eight Multifunction spoilers(MFSs)
3. Two ground spoilers
4. Four flaps
5. Eight slats

Question 3

FBWS controls all surfaces except:

Answer 3

Flaps and slats

*controlled from lever in cockpit.

Question 4

All surfaces are hydraulically actuated except:

Answer 4

HSTAB, which is electromagnetically actuated.

Question 5

Define FBWS in a nutshell!!!

Answer 5

FBWS replaces conventional cable flight controls with an electronic interface that translates pilot commands into aircraft surface positions.

Question 6

Flight deck control inputs are digitized and then sent to:

Answer 6

Three PFCCs where they are converted to electronic commands.

Question 7

After flight deck control inputs are converted to electronic commands:

Answer 7

Commands are then transmitted to 10 Remote Electronic Units(REUs) which position control surfaces through hydraulic actuators.

Question 8

Three PFCCs electronically blend what?

Answer 8

Signals from the flight deck controls, air data and inertial reference inputs, aircraft configuration, and control surface feedback data.

*Commands are computed to operate the flight control surfaces within the aircraft flight envelope(Normal Mode).

Question 9

An internal priority logic selects how many PFCCs to control FBWS?

Answer 9

One is selected; other two monitor in standby mode.

Question 10

What are the two distinct operating modes for FBWS?

Answer 10

Normal and Direct

Question 11

With all component functioning, the FBW system operates in normal mode. The mode is comprised of:

Answer 11

Various pitch, roll, and yaw protections and limits.

Question 12

Depending on system degradation, direct mode is subdivided into:

Answer 12

PFCC direct
REU direct
AFCU direct

Question 13

Normal ground mode is active with aircraft weight on wheels(w.o.w). Characteristics of Normal ground mode are:

Answer 13

1. Direct full travel authority of elevator
2. Pitch rate damping
3. Yaw damping at 70kts and above
4. Direct control of horizontal stab trim
5. Automatic speed bug setting to V2+10. If an engine fails, the speed bug is automatically reset to V2
6. Noseup pitch attitude limit is set to 17 degrees
7. Sidestick shaker stall warning function active above 60kts
8. When both thrust levers are advanced for takeoff, nose down elevator is automatically applied to increase the nose gear loading until speed reaches 90kts.

Question 14

Explain Pitch Compensation!!!

Answer 14

Automatic noseup pitch compensation, to maintain level flight, is provided for bank angles up to 33 degrees. Beyond this bank angle, aft sidestick must be applied!!!!

Question 15

What is trim speed and how is it depicted?

Answer 15

Speed that is adjusted with pitch trim switch on sidestick; it is depicted as an unfilled cyan triangle on the PFD Tape.

Question 16

Normal mode provides longitudinal maneuvering protections which are classified as:

Answer 16

Soft and hard envelope protections

Question 17

Soft envelope limit provides:

Answer 17

Tactile, and in most cases, visual or audio cues, at the edge of the operational envelope.

Example of tactile cues:

stick shaker

Progressive increase in required sidestick force, because there is a built in soft stop within the system, which helps counter continued deflection

The soft stop, in itself, is a cue and can be overcome with force.

Question 18

Hard envelope limit provides:

Answer 18

Limited safe excursion outside the operational envelope, but not beyond the structural limitation of the aircraft.

Question 19

In normal mode, in flight the noseup pitch attitude limit is set to:

Answer 19

30 degrees

*Approaching any of these limits, FBW pitch authority is reduced to prevent excessive pitch(like LSAS)

Question 20

In normal mode Below 110kts, the pitch attitude limit is reduced from 30 degrees to:

Answer 20

20 degrees @ 85kts

*Approaching any of these limits, FBW pitch authority is reduced to prevent excessive pitch(like LSAS)

Question 21

In normal mode, on the ground, the noseup pitch attitude limit is:

Answer 21

17 degrees

*Approaching any of these limits, FBW pitch authority is reduced to prevent excessive pitch(like LSAS)

Question 22

The nose down pitch attitude is limited to:

Answer 22

• 20 degrees

* Approaching any of these limits, FBW pitch authority is reduced to prevent excessive pitch(like LSAS)

Question 23

VAOA Soft is:

Answer 23

High angle-of-attack protection that ensures the operational AOA is not exceeded @ sidestick soft stop

Question 24

VAOA Hard is:

Answer 24

High angle-of-attack protection that ensures the operational AOA is not exceeded @ sidestick hard stop

Question 25

True or False | Overspeed protection is only active when slats/flaps are retracted?

Answer 25

True

Question 26

FBW limits bank angle to a maximum of:

Answer 26

80 degrees *This limit reduces when near the aircraft operational flight envelope.

Question 27

During maneuvers exceeding 1.55 g, ailerons are positioned trailing edge up to prevent:

Answer 27

Wing root bending

Question 28

On a failed engine, the aircraft automatically rolls into a bank and slip of:

Answer 28

20 degrees or less of bank and a sideslip angle of 5 degrees or less.