Autoflight Flashcards
What are the FCCs?
The Flight Control Computers are the brains and controllers of the auto-flight system. There are 2 (A and B). They are a central hub for processing.
What do FCCs calculate?
They calculate pitch and roll for the autoflight system
What FCC does the autothrottle use?
FCC A
What are FCCs powered by?
On-side DC BUS (i.e. FCC A powered by DC Bus #1)
FCCs receive pitch and heading data from…?
The on-side IRS
FCCs receive roll data from…?
The off-side IRS
How many CPUs does each FCC have?
Two 16 bit CPUs
The FCCs also control:
1
2
3
Speed trim
Mach trim
Alt alerting system
How many autopilot actuators are there?
4
Each FCC controls one……..and one…… actuator
Aileron……Elevator
FCC A controls actuators powered by which hydraulic system?
A
FCC B controls actuators powered by which hydraulic system?
B
How much control column force is needed to override a jam within an actuator?
100 pounds
The changeover altitude from speed to mach is at what FL approx?
FL260
What is the speed range in the speed window in knots?
100kt - 340kt
What is VNAV SPD?
Target FMC speed
What is VNAV PTH?
Target FMC vertical speed
VNAV guidance becomes available at….ft?
400ft AGL
LNAV guidance becomes available at….ft?
50ft AGL
What are the bank angle limits of LNAV?
8 deg blow 200ft AGL
30 deg above 200ft AGL
What is the latest altitude you can engage the second A/P on the approach?
800ft RA
When APP is captured, what 3 things would disengage it?
TO/GA
Disengaging A/Ps and both FDs off
Retuning VHF nav
What is the range in the altitude window!
0 - 50.000ft
One revolution of the ALT knob will change altitude by how many feet?
6400ft
What does a green light on an MCP button mean?
That the selected mode can be deselected by pushing again
How many generators are required for a dual channel approach?
2
With a dual channel approach with SINGLE CH displayed and after LOC capture, the G/S and LOC display should flash amber. What does this mean and what should happen next?
The pitch monitor confidence and ILS deviator monitor test has been passed after passing 1500ft RA
SINGLE CH is replaced by CMD
If FLARE doesn’t arm by……ft RA, what should happen to the autopilot?
350ft RA
A/P should disconnect
When will the A/T disengage on a dual channel approach?
2 seconds after touchdown
During takeoff, the F/Ds command 15 deg nose up until sufficient ROC, then what will happen?
Will command MCP V2 + 20kt
During takeoff, when will THR HLD be displayed?
84kt up to 800ft RA followed by ARM
One push of TO/GA will give thrust for roughly what rate of climb on 2 engines?
What speed would you expect from the pitch commands?
1000 - 2000fpm
Manouvering speed for current flap setting at MTOW
Engine failure during takeoff, what would be the pitch expected from the F/D?
13 deg
Which 2 systems deal with windshear detection?
Weather radar and GPWS
What is the initial climb rate you would expect in a windshear escape manoeuvre?
+600fpm
CWS rolls wings level and holds heading when control pressure is released, with a bank angle less that what…?
6 deg
When will the A/P revert to CWS R/CWS P?
1.
2.
3.
4.
1- In approach mode when VHF nav freq is detuned
2- In LNAV/VNAV mode and FMC fails
3- F/D only in use, with pitch roll > half scale before selecting CMD A or B
The CWS heading hold feature is inhibited when?
1.
2.
3.
1 - <1500ft RA with gear down
2- After LOC capture in APP mode
3- After VOR capture with TAS <250kt
When pressing an A/P disengage switch, what happens?
28V DC power to the FCC A, FCC B and MCP is stopped
How much force, when applied to the control column, would disengage the Autopilot with:
Channel A or B engaged?
Channels A and B engaged?
11kg aprox
22kg aprox
With RA inoperative, the A/P would disconnect……seconds after LOC and G/S capture
2 seconds
The Autoflight Status Annunciator (A/P P/RST) will show steady red under what conditions?
1.
2.
3.
1- When stabilizer is out of trim below 800ft RA on dual channel approach
2- ALT ACQ mode is inhibited during A/P go-around if the stabilizer is not trimmed for A/P operation
3- The automatic go-around system fails
What does a flashing amber Autoflight Status Annunciator (A/P P/RST) indicate?
That the A/P has reverted to CWS P or CWS R while in CMD
The A/T will disengage when the thrust levers are apart by how much?
More than 10 deg apart
During takeoff, V2 cannot be changed after passing what speed?
60kts
If MCP alt is not lowered within 5nm prior to reaching top of descent point, what message will appear on the scratchpad?
RESET MCP ALT
VNAV will limit speed to……kt when descending through FL100?
240kts
VNAV will not allow descent below a speed restriction alt until the speed is….?
<10kt from the speed restriction
In approach logic VNAV will continue descent when MCP alt is set above current alt by….?
More than 300ft
FMA will show VNAV PTH when within 200ft of calculated descent path.
What will it be >200ft above?
200 ft or below?
VNAV SPD
VNAV PTH but commands V/S 0fpm
What is the criteria to engage Approach Logic?
1)
or
2)
whichever occurs first
1- 2nm from first app waypoint or
2- 2000ft above field elevation wichever occurs first
What does ADIRS stand for?
Air data iniertial reference system
What is an ADIRS?
ADIRS combine inertial reference units (IRU) and the air data computers (ADC) into onne LRU (line replaceable unit)
