Autopilot Flashcards
What do the flight directors do
Help us make aircraft do what we want
Shows control input direction and magnitude required to follow trajectory
No scale
DOES NOT SHOW DISPLACEMENT
Must be followed if on
What are the flight director modes
Roll:
Heading
LNAV
VOR/LOC
Pitch : Level change VNAV Glide slope Vertical speed Alt hold
What is flight director active mode
Green
Current parameter
What is flight director mode armed
White with smaller font
Automatically engaged when within tolerance
What is flight director mode reversion
Automatic change of mode
Loss of guidance
Change of parameter during capture
What does a autopilot control
Roll
Pitch
Rudder = required for autoland and balanced turns = NOT a yaw damper
Simplest form = maintains a set bank
What is a open loop
No feedback = no measures response
= likely to lead to oscillations / loss of control
= not suitable for autopilots
what is a closed loop
Feedback = measured response
= used for autopilots
= May enter into self induced oscillations
What do you do if the autopilot misbehaves
Disconnect
What is the autopilot inner loop
Basic stability reference a datum
Provides aircraft control
What is autopilot outer loop
Pilots selection of parameter
Adjust datum for inner loop
Provides aircraft guidance
What is the autopilot piloting signal
Compared where you are to where you want to be
Input to autopilot computer
Epsilon
What is the autopilot controlling signal
Output from autopilot computer
Beta Charlie
Subject to control laws = never have more than x° angle of bank
Control law for fly by wire less restrictive than control laws for autopilot
What is automatic synchronisation
Ensures smooth engagement of autopilot
Operates when autopilot is off
Prevents snatching of controls
What is autotrim
Operates when autopilot is engaged
Ensures a smooth disconnect
No change to aircraft trajectory
When autopilot drops out = nothing happens
What happens when manual trim is used when autopilot is on
Disconnects
What fluid is inside of a actuator
Hydraulic
What is an actuator
Converts electrical signals to motions
What are the 2 types of actuator
Series:
Control column remains static
Parallel type:
Control column moves with surface movement
What is autothrust controlled by
controls engines through FADEC
fuel authority digital engine control
What autothrust modes are “thrust fixed”
TOGA N1 MCT IDLE ARM
What autothrust modes does thrust change
Speed
What is pitch priority
Pitch channel fixed to parameter
Thrust controls speed
V/s, g/s, ALT, VNAV
May be mismanaged
What is speed priority
Thrust at fixed setting
Pitch controls speed
Level change, stall reverence speed, open climb, open descent
Speed “safe”
Vertical speed may become excessive
How will the autopilot intercept a localiser
Will overshoot the centre like slightly to create a positive interception
When approach is engaged how many autopilots are on
2 for redundancy
What is fail operational
2 or more autopilots
If only 2 then there is a 3rd monitoring circuit
If 1 autopilot fails = now fail passive
What is fail passive
One autopilot
No redundancy
If autopilot fails = manual flight
Lowest cat after failure = CAT 1
What is alert height
The height that below which most earnings will be silenced
What warnings will still be heard below alerts height
Ils drop out
Rad alt failure
If both autopilots fail
What is the datums for autoland
Rad alt
Ils
What is control wheel steering (CWS)
Autopilot is engaged
Using autopilot actuators to move control surfaces
Pilot provides piloting signal
Still subject to control laws
Appropriate modes must be engaged afterwards
What is touch control steering (TCS)
Autopilot is put on “hold” / “ pause”
Using normal control actuators
Autopilot reverts to previous modes afterwards
