Autopilot Flashcards
What is the difference between inner loop and outer loop?
inner loop systems provide the controls, outer loop systems provide the data which will ‘close the loop’. I.e. altitude not held (detected by outer loop), inner loop is closed and causes controls to fix deviation.
What do rate dampeners and torque limiters do?
Assist the feedback comparator signal to prevent autopilot runaways
What movement does a single axis autopilot control?
Roll (lateral stabilisation)
What movement does a ‘two axis’ autopilot control?
Roll and pitch (lateral and longitudinal stabilisation)
What movement does a ‘three axis’ autopilot control?
Roll, pitch, yaw.
How many inner loops will an autopilot system have?
An amount equal to the amount of axes controlled. single axis = 1, two axis = 2, 3 axis = 3.
How many autopilots do most large aircraft typically have?
2 or 3, the purpose of this is for redundancy and cross-checking
What is the CADC?
Central Air Data Computer: Receives manometric data from the pitot static system and TAT. Can calculate IAS, TAS, Mach #, and pressure altitude.
How does the CADC use data for the autopilot?
Converts pressure signals to electrical signals
What phases of flight can the autothrottle be engaged in?
All stages
What is used to control airspeed during a climb or descent, attitude or throttles?
Attitude (power remains constant)
What is used to control airspeed, attitude or power?
Power. Though attitude is also changed to maintain correct power + attitude.
When operating on autopilot on a VOR, what does the system do once the cone of confusion is entered?
reverts to HDG hold mode, until signal returns again.
What is CWS (Control Wheel Steering)?
Allows the pilot to manually control the aircraft without disengaging to autopilot. Once the CWS is released, the AP will hold the now AoB or Attitude.
What is the difference between series-connected and parallel connected servomotors in an autopilot system?
In series, the pilot’s controls don’t move.
In parallel, the pilot’s controls move. (DA40 has parallel)
What is the purpose of the torque limiter?
Prevents the controls being deflected too strongly (AP can’t ‘feel), so will disengage the servomotors is a certain threshold is exceeded.
What is autopilot hardover, and how is it managed?
Tendency for autopilot to use FULL deflection. Prevented by the torque limiter.
How many autopilots are required for autoland?
2
What are the two types of autoland systems? Explain.
Fail passive (soft): In the event of a system failure, the flight path will be maintained, but the autolanding will not be done. Fail operational. If a failure of one AP occurs, the landing will still be completed because it just turns into a fully functional 'fail passive system'.
How many autopilots does a fail passive system have?
- This is why the approach must be manually flown in the event of a failure, because autoland cannot be done with one autopilot.
How many autopilots does a fail operational system have?
- If one of the autopilots fails, it simply reverts to ‘fail passive’ mode.
What are the three ‘fail operational’ settings?
Land 3: indicates 3 channels are engaged.
Land 2: Indicates 2 channels are engaged, therefore reverts to a ‘fail passive’ system.
No autoland: Only 1 channel available, therefore autoland not possible.
In the event of 1 channel failing in a fail passive system, what will happen?
warnings displayed to the pilot, and autopilot will disengage itself at 350ft RADALT.
At what altitude does a RADALT become active?
2500ft
