Secondary Flight Contols

Question 1

Examples of secondary flight controls

Answer 1

Flaps, trimming devices, slats, spoilers, speed brakes

Anything that doesn’t control a/c attitude but provides a finer control over the a/c and ease pilot workload

Question 2

Flap operation

Answer 2

Flight deck selector - flap shaped to be tactile distinctive - produces an input to the slat/flap computers - control monitor and test the operation of the flaps

Electrically controlled hydromechanical unit drives the transmission which drives the flaps

Question 3

Leading edge slats

Answer 3

Variable posn = retracted, intermediate, fully extended - slat with a slot

Leading edge flaps only have 2 posn

Question 4

Operation of leading edge devices - sequence

Answer 4

Leading edge flaps extend fully - slats to the intermediate posn when the trailing edge flaps move into the intermediate posn

When trailing is fully lowered - slats extend fully

Sequence is reversed for retraction

Question 5

Leading edge devices operation

Answer 5

Hydraulic motor drives a gearbox which drives a series of torque shafts

Question 6

Leading edge devices - alternate operation

Answer 6

Can be extended electrically but some a/c - cant get it back up once extended

Question 7

LRS - flap limiter

Answer 7

Retracts the flaps to the mid posn if the airspeed exceeds a predetermined speed

Automatically returns to fully extended when the speed reduces

Question 8

Flap asymmetry protection

Answer 8

Interrupts flap movement when it is detected - locks it out

Isolates the flap selector lever

Sends a warning into the f/d

Question 9

Autoslat system

Answer 9

Automatically deploys slats to the fully extend posn if the a/c is close to reaching stalling AoA

Question 10

Alternate flap operation ALT posn

Answer 10

Operates a electrically driven back up system

Disables normal flap control

Arms the alternate mode

Engages electric motors

Disables ink which operates slats in conjunction with flaps

Question 11

Ideal speed brake location

Answer 11

Fuselage - increase of drag with a limited loss of lift

Question 12

Speed brake - armed mode

Answer 12

Will not work until certain conditions are met

Req a signal from 2 separate wheels

Ground shutoff valve ensures ground spoilers are used only on the ground

Question 13

Spoiler operation

Answer 13

Aileron PFCU movement actuates the aileron and simultaneously sends a roll control signal to the spoiler mixer

Question 14

Flight spoiler hydraulic power is controlled by

Answer 14

Electric motor driven valves - situated in the flight control power system - allows spoilers to be isolated if required

2 spoiler switches individually control the valves

Question 15

Flap systems are operated by

Answer 15

Screw jacks - forms a mechanical lock

Question 16

Blow back - spoilers

Answer 16

Speed brakes/spoilers have no mechanical lock like flaps so if hydraulic power is lost they will trail or blow back