Secondary Flight Controls Flashcards
Definition of secondary flight controls
Does not directly alter pitch,bank or yaw of A/C
Secondary Flight Controls Include
TE flaps
LE flaps
Trimmers
Spoilers
Speed brakes
Light A/C secondary flight controls
Flaps - Mechanically driven by lever
Trim Tab - Operated manually
LE slats
OFTEN operated manually
Flap Asymmetry Protection
If one fails to extend over the other
Interrupt flap movement when flap positions disagree
Detect and switch off power to whole system
Isolate selector handles
Leading Edge Devices
Droop Nose
Krueger Flap
Leading edge flap
Slats
ALTN FLAPS control
Disabled normal flap control
Arms alternate mode
Engages electric motors
Disables the link which operates slats in conjunction with flaps
Speed Brakes and Spoilers
Speed brakes and spoilers same device but different functions
Flap like panels
Spoilers - one is slightly raised more than the other for assisted roll
Speed Brakes - Max extension on both sides to lift dump
Mechanical Locking
Screw jack system extending and retracting flaps form natural mechanical lock
Blow back system on speed brakes
No lock on them so as soon as power lost forced back by air pressure
In order to initiate wing spoilers in lift dump mode the following conditions must be met…
Speed brake lever in armed detect
Wheels rotating
Aircraft weight on the undercarriage
Load relief system - secondary flight controls
Protection against flap damage and auto retract when overspeed and extend back once speed back in envelope
How do spoilers operate?
On upper surface only work symmetrical and asymmetrical
One slightly extended on one wing they act asymmetrically as spoilers to assist with roll control
Krueger Flaps location + role
Used on inboard section of leading edge of wing
Actuator extends the flaps outwards increasing the camber of the wing but retains small radius of LE
Ensure wing root stalls before tips
Ground Spoilers role and req needed to operate
Maximise wheel brake efficieny by spoiling the lift generated by wing forcing full weight on landing gear
Only operate on ground due to spoiler shut off valve that is closed until main landing gear operates weight on switch
Autoslat function
Extend slats automatically if wing is about to stall
