Primary flight controls Flashcards
What are the primary flight controlls
Pitch - Elevators
Roll - Aileron (plus roll spoilers)
Yaw - Rudder
Means of actuation: (3)
Manual: cables, pulleys, bell cranks
Partially powered: Cables and leavers with actuator assistance
Fully powered: No mechanical connection between pilot’s control and control surfaces
Describe reversable controls
Feedback from the control surface to the pilot controls
If forces on the aerofoil are felt in the flight controls, it is what kind of control?
Manual / partially powered / fully powered
Manual - it’s connected by cables.
(reversable)
What is this describing and is it reversable?
Hydraulic actuator attached in parallel to mechanical linkages. Movements of the pilot’s controls simultaneously move the control surface and a servo, which moves the actuator.
Partially powered system
reversable
What is this describing and is it reversable?
The pilot’s controls use mechanical or electrical methods to operate a servo value controlling an actuator which moves the control surface.
Fully powered
non-reversable
‘Feel’ or feedback is useful because
Means the pilot is unlikely to overstress the aircraft. Without, it would be easy to go full deflection on the controls at high speed.
Fly-by-wire modes?
Normal
Degraded
Direct law
Describe Fly-by-wire degraded
aka Airbus Alternative law
Some protections and finessing absent
Describe Fly-by-wise Direct law
All computer mediation absent
FBW disadvantages are?
Sensor failure renders the system useless
Sidestick controller issues (AF447)
One pilot can’t see or feel the other
THS stands for?
Trimmable Horizontal Stabiliser
FBW system components are:
Actuators - to move controls
Computers - to interpret commands
Control surface position sensors - to provide feedback to computers
Triplicated or quadruplicated control wires running through different parts of the airframe
Trimming functions are available on primary controls, what do they do?
Null the loads felt by the pilot.
What does a trim tab do?
Creates a balancing load at the control surface
THS, trimmable horizontal stabiliser is very powerful, give an example of this going wrong
Runaway stab
or
MAXs
What do control locks do?
Protect reversable controls from banging against stops in gusty conditions.
Check for what being removed before flight (to do with controls)?
Control locks
Rudder limiter / ratio changer does what and why?
Limits the rudder travel at high speeds.
Leaves full deflection at low speed for asymmetric thrust in climb conditions
The difference between Boeing and Airbus FBW systems is:
Hard law - Airbus
Soft law - Boeing
In Boeing - what does ACE stand for and mean
Actuators comprise of 4 Actuator Control Electronic (ACE) units
The ACE is a Electro-hydraulic self-contained unit that has a dedicated hydraulic pump and oil supply and fitted directly to the control surface.
