Flight Controls Flashcards
ACEs?
Actuator Control Electronics (4)
PFCs?
Primary Flight Computers (3)
Roll control is provided by what surfaces?
Ailerons, flaperons and assymetric spoilers
Ailerons?
Outboard of the flaps
Assist with roll control only in low speed flight
Locked out during high speed flight
Droop with flaps
How many PCUs on the rudder?
3
Each is powered by a different hydraulic system
How many slats are there?
12
Control Input path for manual flight?
Pilot inputs to ACEs
ACEs sends electronic signals to PFCs
PFCs calculate inputs and send them back to ACEs
ACEs then convert back to analog and send signals to PCUs
What are the inputs to the PFCs?
Air data
Inertial data
Flap and slat position
Engine thrust
Radio altitude
Control path for auto flight?
Pilot inputs to MCP
MCP signals to PFCs
PFC signals to ACEs
ACEs mechanical signals to PCUs
Why should the flight controls not be moved after landing?
After landing with the flaps retracted and speed below 30 knots, a series of flight control self-tests are run, and take approx. 90 seconds to complete
Moving the flight controls interrupt these tests
When are flight control self-tests performed?
After landing with speed less than 30 knots and flaps retracted
After shutdown with external power connected
Hydraulics should not be shut off
Controls should not be moved
Flaps and speed brake lever should not e moved
If two consecutive flights pass without uninterrupted self-tests, error message
What causes PFCs to revert to secondary mode?
Inertial or air data is insufficient
OR
All slat and flap position data is unavailable
FLIGHT CONTROL MODE EICAS?
Primary flight control system is in secondary mode
In which flight control modes is the autopilot available?
Only normal mode
How is secondary mode different from manual normal mode?
The PFCs use simplified computations to generate the flight control commands
What functions are not available in secondary mode, (nor in direct mode, for that matter)
Autopilot Auto speed brakes Pitch compensation Gust suppression Roll / yaw asymmetry compensation Tail strike protection Envelope protection
When do the ACEs automatically transition to direct mode?
ACEs detect failure of all three PFCs or lose communication with them
How do you manually select direct mode?
Move the PRIMARY FLIGHT COMPUTERS disconnect switch to disconnect
PRI FLIGHT COMPUTERS EICAS?
Flight control system is in direct mode
Flight control input path in direct mode?
Pilot inputs received by the ACEs are sent directly to the PCUs
For turns with bank angle less than ________ degrees, no back pressure on the column is required
30 degrees
When does the stab trim indication on the EICAS blank?
Gear is up for 10 seconds
OR
60 seconds after liftoff
When does stab trim pointer, box and digital readout display in white?
When outside of the green band
The stab trim pointer, the box and digital readout are all in amber (readout indicates “x”)
Stab trim is inoperative
The pointer will remain on the scale at the last known position