737 Automatic Flight Flashcards
Explain the meaning of the green light in any MCP Mode Selector Switch?
Indicates mode selection and can be deselected by pushing the switch again.
Explain meaning of Master (MA) F/D indicator light.
If neither AutoPilot is engaged the first F/D that is turned on is the Master which is indicated by the MA in green light above the F/D
If one or both of the A/Ps is engaged in CMD, the FCC for the CMD that was chosen first (CMD A or CMD B buttons) is the master FCC.
Which roll modes are affected by the bank angle selector?
HDG SEL and VOR
Describe the manual methods for Autothrottle engagement and disengagement.
What is the main way the auto throttle is disengaged ?
Are there other conditions that will cause the A/T to disengage?j
First move A/T switch to ARM.
A/T will ENGAGE if in the following pitch modes:
LVL CHG
VNAV
ALT ACQ
V/S
ALT HLD
G/S capture
TO/GA
A/T will DISENGAGE if:
Pushing either A/T disengage switch on thrust levers
Autothrottle may automatically disengage when:
* 2 seconds have elapsed since landing
* thrust levers become separated more than 10 degrees except during takeoff
* significant thrust difference along with control wheel roll input of 10 degrees or more.
Explain what the color green represents in the FMA.
What does a green box represent?
Engaged or Captured mode.
A mode change has happened and the box will stay lit for 10 seconds
What does the color white represent n the FMA?
Armed mode.
Explain the different meanings of the AFDS Autopilot Status Annunciations:
CMD (green) FD (green), CWS P (orange), CWS R (orange), SINGLE CH (Orange color), SINGLE CH (Green color) and AUTOPILOT (Flashing Amber)
CMD (Green) - one or both autopilots are engaged
FD (Green) - flight director is ON and the autopilot is either OFF or engaged in CWS mode
CWS P (orange) - pitch mode engaged in CWS
CWS R (orange) - roll mode engaged in CWS
SINGLE CH (Amber) - For single channel A/P ILS approach, annunciates after localizer capture and remains on for entire approach. For dual A/P ILS approach, annunciates after localizer capture and extinguishes after pitch monitor confidence test is successfully completed then goes to green CMD I had about 1500 RA.
SINGLE CH (green) - For and IAN approach annunciates after FAC capture and remains on until AP disengaged or 100 ft RA.
AUTOPILOT (flashing amber) - Autopilot remains engaged below 100ft RA for an IAN approach
What conditions must be met before a second autopilot can be engaged.
- Both VHF Nav freqs tuned in
- APP mode selected
- Second A/P engaged in CMD prior to 800ft RA
Explain function of the A/P DISENGAGE bar.
Pull down:
* exposes yellow background
* disengages both A/Ps
* Prevent A/P engagement
Lift up:
* conceals yellow background
* enables autopilot engagement
What is the meaning of the illuminated Amber A/P Disengage light on the forward panel?
A/P amber and flashing means Autopilot reverted to CWS pitch or roll while in CMD
Explain meaning of Red A/P Autopilot Disengage light on the forward panel when it is:
1. Red and Flashing
2. Red and Steady - 3 possible meanings
RED and FLASHING - flashes and tone sounds when autopilot has disengaged.
RED and STEADY ( 3 possible meaning)
1. Stabilizer our of trim below 800 ft RA on dual channel approach
2. ALT ACQ mode inhibited during A/P go-around if stabilizer not trimmed for single A/P operations
3. Automatic ground systems tests fail
What is the indication of a disengaged Autothrottle?
Flashing red A/T P/RST light on the forward panel
Explain meaning of STAB OUT OF TRIM (amber) light on the left forward panel
A/P not trimming stabilizer properly. Light will only come on with A/P engaged.
Explain what will happen on approach when TO/GA is selected below 2000 ft RA.
- If No A/P or single A/P engaged: disconnects autopilot (if engaged) and requires manual F/D go around.
- If Both A/Ps engaged (with FLARE armed on the FMA): A/P go around mode is activated. A/Ps remain engaged.
What happens if TO/GA is pressed once during go around?
What if it is pressed a second time?
First push: A/T provides reduced go around N1 to produce 1000 to 2000 fpm rate of climb.
Second push: A/T advances to the full go around N1 limit.
Where are the AFDS Flight Mode Annunciators (FMA) and what does each position represent?
They are just above the attitude indicator and represent Autothrottle, Roll, and Pitch modes.
Explain the AFDS FMA Autothrottle Modes.
N1, GA, RETARD, FMC SPD, MCP SPD, THR HLD (all green)
- N1 - the auto throttle maintains thrust at the selected N1 limit displayed on the thrust mode display
- GA - the auto throttle maintains thrust at reduced go around setting
- RETARD - displayed while auto throttle moves lever to the aft stop. Once the levers have finished moving to the aft stop the display will switch to a white ARM mode.
- FMC SPD - A/T maintains speed commanded by the FMC
- MCP SPD - auto throttle maintains speed set in the MCP IAS/MACH display.
*THR HLD - the A/T servos are inhibited allowing pilot to set levers manually.
- ARM (white) - no A/T mode engaged but minimum speed protection is provided. The pilot is free to shift the position of the throttles while in ARM mode just like in THR HLD mode.
Explain meaning of the AFDS FMA Pitch modes.
TO/GA, VNAV SPD, VNAV PTH, V/S, ALT ACQ, ALT HOLD, MCP SPD, G/S (white and green), FLARE (white), FLARE (green), G/P (white and green)
TO/GA - (takeoff) engaged with FDs on and TO/GA switch pressed
TO/GA - (go around) - engaged by pressing TO/GA switch under following conditions:
- inflight below 2000 ft
- in flight above 2000 ft with flaps not up nor G/S captured
- not in takeoff mode
- either F/D ON or OFF
VNAV SPD - the AFDS maintains the FMC speed displayed on the airspeed indicator and/or the CDU CLIMB or DESCENT pages
VNAV PTH - the AFDS maintains FMC altitude or descent path with pitch commands
V/S - engaged - commands pitch to hold selected V/S
ALT ACQ - transition maneuver entered automatically from a V/S, LVL CHG or VNAV climb/descent to selected MCP altitude
ALT HOLD - commands pitch to hold MCP selected altitude
MCP SPD - pitch commands maintain IAS/MACH window speed
FLARE armed (white) - during a dual A/P approach, FLARE is displayed after LOC and G/S capture and below 1500 ft RA. The second A/P couples with the flight controls and A/P go around mode arms.
FLARE engaged (green) during a dual A/P approach, flare engages at 50 feet RA. FLARE accomplishes the auto land flare maneuver.
When VNAV is pushed it commands the AFDS to follow vertical guidance provided by the FMC.
What is the difference between VNAV SPEED and VNAV PATH?
In VNAV SPEED mode pitch controls the airspeed while rate of climb or descent is controlled by thrust.
In VNAV PATH mode pitch controls the vertical flight path and the autothrottles vary the thrust to hold the commanded speed.
** When VNAV is pressed the mode will initially go into VNAV SPEED and then change to VNAV PATH once the FMC cruise altitude is reached. **
Explain meaning of AFDS FMA Roll Modes: LNAV (green and white), HDG SEL (green), VOR/LOC (green and white), FAC (white and green), B/CRS (white and green).
LNAV (white) - the AFDS is armed (prior to takeoff) to engage LNAV at 50 ft RA.
LNAV (white) - the approach phase and missed approach exist in the flight plan
LNAV (green) engaged - the AFDS intercepts and tracks the active FMC route
HDG SEL (green) - self explanatory
VOR/LOC (green and white) - self explanatory
FAC (armed) white - the AFDS is armed to capture the IAN approach course
FAC (green) engaged - the AFDS tracks the IAN final approach course along the inbound course bearing
B/CRS - self explanatory and DELTA does not use back courses in the 737
How is an Integrated Approach Navigation mode armed? What are the modes?
Select the APP button. Once armed the autopilot/FD will capture and track the localizer/final approach course and glide slope or glide path.
ILS approach - VOR/LOC and G/S will be displayed
FMC IAN approach - FAC and G/P will be displayed
ILS approach with G/S off or LOC approach only - VOR/LOC will be displayed along with G/P.
Explain function of SPEED switch on the MCP.
Push on to engage A/T in SPEED mode - maintains speed in MCP/IAS display.
Note: Normally Autothrottle SPEED modes are automatically engaged with the selection of compatible pitch modes without making a separate selection.
Explain Speed Intervention SPD INTV Switch.
There is only one mode in which it can be used. What is this mode?
Push only when VNAV is engaged
* It allows the crew to change the FMC target speed on the MCP while remaining in VNAV. This is referred to as “opening the window” and is the preferred way to change the speed when ATC gives some sort of speed restriction.
Explain function of VNAV switch.
- pitch mode annunciates VNAV SPD, VNAV PTH (both green)
- autothrottle mode annunciates N1 for climb or RETARD followed by ARM (white) for descent
- IAS/MACH display and airspeed cursors display target speed
What is the function of the Altitude Hold (ALT HLD) switch on the MCP?
engages ALT HOLD command mode - holds altitude at whatever altitude at which it was pushed
What is the function of the V/S mode?
- arms or engages V/S command mode
- engages A/T in speed mode to hold selected airspeed
What is the function of the altitude Intervention Switch?
Allows crew to:
1. Change the FMC target altitude with the MCP altitude selector
- Climb and descend from level-off altitude
- Delete altitude constraints in the flight plan
Explain function of LNAV Switch
- Commands AFDS roll mode to intercept and track the active FMC route
What is the function of the LOC switch
Commands AFDS roll mode to capture the selected VOR or LOC course.
What is the purpose of the CMD switch on the MCP (Mode Control Panel)?
Engages A/P and enables all command modes. Puts CMD on the status display
What is the CWS switch function?
Engages A/P and enables pilot to input control control column to the pitch and roll servos.
What are the speed condition symbols (flashing A or Flashing 8) on the MCP?
Overspeed or underspeed Limiting Symbols appear when commanded speed cannot be reached.
Underspeed limiting - flashing character “A”
Overspeed limiting - flashing character “8”
occurs with:
- Vmo or Mmo limit
- Landing gear limit
- flap limit
Change over speed happens at what altitude?
26,000 ft
What is the function of the N1 switch?
- engages A/T in N1 mode if compatible with AFDS modes already engaged.
Note: engages automatically with certain pitch modes.
If TO/GA is selected for Go-around during Autoland operations with FLARE armed and LNAV armed at what altitude will LNAV engage?
50 feet
What three locations show the status of the auto flight (AFDS) system
- The Flight Mode Annunciator (FMA)
- AFDS Status Annunciator (just below the FMA)
- Thrust mode display (just above the engine instruments display)
The MCP can be broken up into four sections:
1. Speed control
2. Lateral control
3. Vertical control
4. Engage/Disengage switches
Under which of these section can the crew find the VNAV switch?
VNAV switch is in the Speed control section of the MCP
What does the ALT INTV switch do?
Altitude Intervention switch allows modifications to altitude constraints and initiates climbs and descents in VNAV
When can a roll mode NOT be deselected?
When on an approach and the APP mode has already captured the localizer and glide slope.
When will both green MA (master) lights be displayed at the same time?
- In the TO/GA mode below 400 feet AGL.
- When APP is engaged and LOC and GS are captured.
- When there are discrepancies between the FCC (flight control computers) resulting in independent Flight Director operation.
When two autopilots are engaged, which one is the master?
The autopilot that was engaged first is the master autopilot when two A/Ps are engaged simultaneously.
What does an amber flashing A/P P/RST light on the panel mean?
That the Autopilot has reverted to the CWS mode.
What happens to the autopilot if the pilot overrides the autopilot with force?
The autopilot will revert to CWS mode.
What three things will keep the autopilot from being engaged?
- Force being put applied to the control wheel while engaging autopilot.
- Trim Cut out switch in the CUT OUT position
- Engage/Disengage autopilot switch in the Disengage position.
When can both autopilots be engaged simultaneously?
Only when in the APP mode.
NOTE: When flying an IAN approach two autopilots can never be engaged even when in the APP mode
When auto throttles are engaged when can the pilot manually override them.
Anytime.
When does the Autothrottle switch from N1 mode to THR HLD mode during takeoff?
At 84 kts
How many miles out from an active route will the LNAV engage no matter what the heading of the aircraft?
3 miles.
If more than 3 miles then the aircraft must have an intercept angle of 90 degrees or less and before the active waypoint.
How is the auto land function engaged?
See attached.
When given a flight path change what is the preferred way to make the change?
Make the flight path change on the MCP first and then make changes in the FMC. (from 737 VNAV arrival video)
What are the 3 descend via clearance limits?
- Descend via but no runway or landing direction then the crew will put the lowest altitude on the arrival that is common to all runways.
- Descend via with a landing direction such as “Descend via the Hawks arrival landing North” then the lowest altitude will be that which is common to all North bound runways.
- Descend via with a landing direction and a specific runway the crew will enter the altitude of the FAF for that runway.
