AUTOPILOT Flashcards
Describe how the AFDS controls the elevators, ailerons and rudder?
Through the fly-by-wire flight control system. Sends input directly to the PFCs via the AFDCs and then to the ACEs to the PCUs
Which Surface commands are added only during an autopilot approach and landing?
The rudder
Which autopilot modes have an arming phase?
Roll modes: LNAV, LOC, ROLLOUT
Pitch modes: VNAV, G/S, FLARE
Which autopilot mode cannot be disengaged by selection of another mode?
APP mode after LOC or G/S capture
After an ILS capture and above 1’500 ft, what happens if APP mode is reselected?
APP mode deselects and AFDS reverts to default roll & pitch modes
When will override of rudder pedals cause autopilot disengagement?
Only with LAND 2 or LAND 3 annunciated
How does the autopilot react to engaged mode degradation?
Remains engaged in an attitude stabilizing mode initially
How is the flight director affected by an initial mode degradation?
F/D initially command an attitude stabilizing command based on inertial data
With the F/D off, will a TOGA selection cause them to appear?
Yes, if speed is over 80kts and flaps are out of UP
How is the F/D affected by overspeed or stall?
F/D bars will disappear
What two occasions will cause a green box to appear around an FMA mode?
- When a mode is first activated/engaged(green box appears for 10s)
- When amber line through a degraded mode is removed
What is the A/T controlling to when THR is annunciated?
A/T applies thrust to maintain V/S REQD by pitch mode
At what distance to an active route leg will LNAV engage, if armed?
2,5 nm
What are the conditions for the roll mode ATT to engage?
When A/P is engaged and both F/D:s are OFF and bank angle is more than 5 degrees.
When is TOGA mode armed in flight?
Whenever flaps are out or G/S captures
When does ROLLOUT mode engage?
Below 2 ft RA on landing
What are the bank angle limits in ATT mode?
5-30 deg
Less than 5 deg = rolls back to level
More than 30 deg = Rolls back to 30 deg
After take-off, what is the target speed?
When will the higher speed limit be used?
V2+15 up to 25 kts
If speed is above V2+15 for more than 5 sec then speed is reset to a max of V2+25
Where does the AFDS get the V2 speed; MCP or CDU?
AFDS uses the speed set in the MCP IAS/MACH window
When will VNAV engage if armed for T/O?
At 400 ft
After an altitude conflict, how is VNAV ALT mode cancelled?
By changing the altitude value set in the MCP ALT window and pushing the ALT selector, or changing the pitch mode
When does FLARE mode engage?
During autoland between 60-40 ft RA
Can the A/T be operated without the flight director or autopilot?
Yes, but only in THR REF, SPD, HOLD or IDLE modes
Can the A/T engage automatically?
Yes, if armed and no AP or F/D is active
Can the A/T be engaged if only one servo motor is serviceable?
Yes
In which thrust mode will the A/T not reposition the thrust levers?
HOLD mode
What action causes a normal A/T disconnection during landing?
When either thrust reverser lever is raised to reverse or thrust levers are manually overridden during a manual landing
What are the initial TOGA F/D commands upon engagment?
Pitch command is 8 deg nose up
Roll command is wings level
During take-off, when can the TOGO switches be used for A/T engagement?
Speed less than 50 kts on T/O roll or above 400 ft(if not activated by 50 kts)
What does selection of TOGA above 80 kts do?
Disarms LNAV and VNAV
What type of altitude is used for LNAV and VNAV engagements?
LNAV: 50 ft RA
VNAV: 400 ft above rwy elevation
What is the maximum speed commanded after lift off, if an engine fails?
V2 to V2+15 kts
What does a TOGA selection do immediately after T/O?
Removes T/O and climb derates and assumed temp reduction.
A/T actives in THR REF
What is the pitch speed command at acceleration altitude?
5 kts below T/O flap placard speed of the commanded flap position
What is the VNAV climb speed when in clean configuration?
Speed transition associated with origin Airport or VREF+80kts, whichever is higher
What is the A/T mode for a single push go-around?
THR
After a go-around, how can TOGA be terminated below 400ft
Below 400 ft: disengage AP and then turn off both F/D:s or automatic LNAV activation
After reaching the missed approach altitude, what is the auto throttle mode?
SPD
What are the 3 forms of autopilot envelope protection?
Stall protection
Overspeed
Bank angle
What are the roll and pitch modes that engages when A/P is engaged and the F/D:s are OFF?
Roll mode: HDG/TRK Hold or ATT (if bank over 5 deg)
Pitch mode: V/S or FPA
When will the F/D:s automatically display, even if the F/D switches are off?
- TO/GA is pushed and airspeed is greater than 80 kts
- On a go-around with the flaps not retracted
Below what altitude is the CLB/CON thrust switch inoperative?
Below 400 ft during takeoff
What happens in the system when the CLB/CON thrust switch is pushed?
- With 2 engines it changes the engine thrust limit to the FMC selected climb thrust
- With 1 engine it changes the engine thrust limit to maximum continous
When does the MCP speed window change from IAS to MACH?
At 0,84 Mach during climb
When does the MCP speed window change from MACH to IAS?
At 310 kts during descent
What speed is displayed in the MCP speed window when power is first applied to the aircraft?
200 kts
What is displayed in the MCP Heading/Track Window when power is first applied to the aircraft?
360
What is the selectable range for the Vertical Speed?
-8000 to +6000 fpm
What is the selectable range for the FPA?
-9,9 to +9,9 degrees
What is displayed in the MCP Altitude Window when power is first applied to the aircraft?
10’000 ft
Within what angle do you have to be to get Localizer capture?
Within 120 degrees of the localizer course
How can LOC mode be disarmed before LOC capture?
- By pushing the LOC switch a second time
- By arming or activating LNAV
How can LOC mode be disarmed after LOC capture?
- Selecting a roll mode other than LNAV
- Pushing the TO/GA switch
- Disengaging the A/P and turning both F/D:s off
- Pushing the LOC switch a second time as long as you are above 1’500 ft RA
With APP mode armed, can G/S capture happen before LOC capture?
No, it is inhibited
Within what angle do you have to be to get G/P capture?
Within 80 degrees of the LOC course
How can APP mode be disarmed for any status of the LOC and G/S combination?
By disengaging the A/P and turning both F/D:s off
How can APP mode be disarmed with both LOC and G/S armed?
By pushing APP, LOC, LNAV or VNAV
How can APP mode be disarmed with LOC and G/S capture?
By pushing TO/GA
How can APP mode be disarmed with LOC capture and G/S armed?
By pushing HDG/TRK SEL or HDG hold
How and when can the APP mode be deselected above 1500ft without disengaging the A/P?
By pushing the APP switch above 1500 ft RA
What is the initial climb speed after a normal takeoff?
V2+15 to V2+25
What climb rate is the TO/GA system aiming for after a go-around on approach, and what thrust mode is displayed on the FMA?
2’000 ft/min and THR is displayed
On a go-around, what does a second push of the TO/GA switches accomplish?
It activates the A/T in THR REF
Which barometric source does the AFDCs use for baro correction?
The side on which the A/P was engaged.
On ground when both F/Ds are switched on the Captains source is used and an L is displayed in the lower right corner of the PFD
Describe how the electrical system is divided to support LAND 3 AUTOLAND
There are 3 sets of critical autoland components. Each set contains:
- ILS (AC)
- Radio Altimeter (AC)
- AFDC (DC)
- ILS antenna switch (DC)
The left set is powered by L AC XTFR BUS and L DC MAIN BUS with the L IDG as source
The center set is powered by the STBY AC BUS and the BATTERY BUS with the R IDG as source
The right set is powered by the R XTFR BUS and R DC MAIN BUS with the R BACK UP GEN as source
Where are the inputs from the MCP sent to?
Inputs on the MCP is sent to the three ADFCs, they provides control of the F/Ds and A/P. Signals are sent from the AFDCs to the PFCs
In what three ways can the autopilot be disengaged?
Autopilot can be disengaged by :
1. Using the control wheel A/P disengage switch
2. Use the MCP autopilot disengage switch
3. Overriding with the control column or rudder pedals (pedals will only disengage the autopilots with LAND 2 or LAND 3 annunciated)
What does the EICAS message “AUTOPILOT” mean?
the EICAS caution message “AUTOPILOT” displays to indicate that the autopilot is in a degraded mode.
Describe how the auto throttle provides stall protection if not active?
The A/T can automatically activate to provide stall protection when armed but not active. If speed decreases to near stick shaker activation, the A/T automatically activates in SPD mode and advances thrust to maintain minimum maneuvering speed (MMS) or the speed set in the MCP speed window, whichever is greater.
What is the target speed if an engine failure occurs on the ground?
If an engine failure occurs on the ground, the pitch command target speed at lift-off is V2 or the airspeed at lift-off, whichever is greater
What is a requirement for FLARE mode to be armed?
Flare can be armed when LAND 3 or LAND 2 is annunciated on the PFD
In the ROLLOUT mode, what does the autopilot control to track the centerline?
The autopilot controls the rudder and nosewheel steering to keep the aircraft on the centerline.
When will ROLLOUT mode disengage?
Rollout guidance continues until the autopilots are disengaged.
What happens to rudder control during an automatic go-around?
During a go-around from a LAND 2 or LAND 3 approach, automatic LNAV activation causes disengagement of the autopilots control over the rudder. If executing an engine out missed approach with TAC inoperative, manual rudder inputs will be required.
How do you terminate TO/GA mode below and above 400 ft RA?
To terminate TO/GA mode:
- Above 400 ft RA, select a different roll or pitch mode
- Below 400 ft RA, disengage A/P and turn off both F/D
What pitch up degree is commanded when pushing a TO/GA switch during a go-around?
Pushing a TO/GA switch commands a pitch-up of 15 deg or slightly below the pitch limit, whichever is lower. As rate of climb increases, the AFDS transitions from pitch to airspeed control.
