Auto Flight

Question 1

VNAV arm criteria on the ground.

Answer 1

1. Avalid flight plan has been entered;
2. Performance data has been entered and executed;
3. Both flight director switches have been switched on.
   (FCOM 4.10.6)

Question 2

LNAV arming criteria on the ground.

Answer 2

1. Origin runway in flight plan;
2. Active route entered in FMC;
3. Track of first leg within 5 degrees of runway heading;
4. LNAV selected prior to TO/GA.
   (FCOM 4.10.13)

Question 3

LNAV engagement criteria in flight.

Answer 3

1. Active route entered in FMC;
2. Within 3 NM of active route, LNAV engagement occurs with any airplane heading;
3. Outside of 3 NM, airplane must:
   • be on intercept course of 90 degrees or less;
   • intercept route segment before active waypoint.
   (FCOM 4.10.13)

Question 4

Bank Angle Selector in the MCP affects which modes?

Answer 4

HDG SEL or VOR.

FCOM 4.10.15

Question 5

During approach, the second A/P must be engaged until what altitude?

Answer 5

800’ RA.

FCOM 4.10.16

Question 6

After localizer and glideslope capture, APP mode can be disengaged by what actions?

Answer 6

1. Pushing a TO/GA switch;
2. Disengaging autopilot(s) and turning off both F/D switches;
3. Retuning the VHF NAV receiver.
   (FCOM 4.10.16)

Question 7

Autopilot (A/P) Disengage Light: conditions for illumination in red or amber.

Answer 7

Red:
Flashes:
1. Autopilot has disengaged;
2. An autopilot engage attempt is unsuccessful (F, H, I);
Steady:
1. Stabilizer out of trim below 800 feet RA on dual channel approach;
2. ALT ACQ mode inhibited during A/P go–around if stabilizer not trimmed for single A/P operation;
3. Disengage light test switch held in position 2;
4. Automatic ground system tests fail.
Amber:
Flashes: A/P automatically reverts to CWS pitch or roll while in CMD;
Steady: Disengage light test switch held in position 1.
(FCOM 4.10.22)

Question 8

Autothrottle (A/T) Disengage Light: conditions for illumination in red and amber.

Answer 8

Red:
Flashing – autothrottle has disengaged;
Steady – disengage light test switch held in position 2.
Amber:
flashing – indicates A/T airspeed error under following conditions:
• inflight
• flaps not up
• airspeed differs from commanded value by +10 or -5 knots and is not approaching commanded value;
Steady – disengage light test switch held in position 1.
(FCOM 4.10.23)

Question 9

What is the meaning of Autothrottle Limit (A/T LIM) Indication on the upper DU?

Answer 9

FMC is not providing the A/T system with N1 limit values.
The A/T is using a degraded N1 thrust limit from the related EEC.
(FCOM 4.10.24)

Question 10

What is the effect of inoperative RA on the A/P operation?

Answer 10

With a radio altimeter inoperative, the autopilot will disconnect two seconds after LOC and GS capture.
(FCOM 4.20.3)

Question 11

What happens if a generator is lost during a F/D TO or GA, or while in dual F/D APP?

Answer 11

If a generator is lost during a F/D TO or GA, or while in dual F/D APP mode below 800 feet, the FCC on the unaffected side positions the F/D command bars on both attitude indicators.
(FCOM 4.20.4)

Question 12

What’s the difference between A/T HOLD and ARM modes?

Answer 12

In both modes the servos are inhibited, but in ARM minimum speed protection is provided.
(FCOM 4.20.5)

Question 13

Can TO/GA be engaged for takeoff with the F/D switches OFF?

Answer 13

Before commencing the takeoff it cannot be.
TO/GA can be engaged for takeoff with F/D switches OFF if a TO/GA switch is pushed after 80 knots IAS below 2000 feet AGL and prior to 150 seconds after lift–off.
(FCOM 4.20.5)

Question 14

Under which conditions TO/GA, when pushed, will be engaged for go-around?

Answer 14

1.Inflight below 2000 feet radio altitude;
2.Inflight above 2000 feet radio altitude with flaps not up or G/S captured;
3. Not in takeoff mode.
(FCOM 4.20.5)

Question 15

CWS features:
Under what roll angle the mode automatically returns to level flight?
What are the altitude hold capabilities?
Can it be used to intercept VOR radial?

Answer 15

1. If aileron pressure is released with 6 degrees or less bank, the A/P rolls the wings level and holds existing heading;
2. If pitch is manually overridden while in ALT HOLD, the modes changes to CWS P. If control force is released within 250 feet of the selected altitude, CWS P changes to ALT ACQ, the airplane returns to the selected altitude, and ALT HOLD engages;
3. CWS R with a CMD engage switch illuminated can be used to capture a selected radio course while the VOR/LOC or APP mode is armed.
   (FCOM 4.2.7-8)

Question 16

What are the F/D pitch commands when engine failure occurs during the takeoff?

Answer 16

If an engine failure occurs during takeoff, the pitch command target speed is:
1. V2, if airspeed is below V2;
2. Existing speed, if airspeed is between V2 and V2 + 20;
3. V2 + 20, if airspeed is above V2 + 20.
(FCOM 4.20.11)

Question 17

A/P in APP mode - under which conditions the AP will disengage?

Answer 17

1. If the pilot is flying manually but not following the approach flight director guidance and then selects an autopilot CMD engagement, the autopilot reverts to CWS for the pitch and roll mode.
2. After FLARE ARM annunciation, any attempted manual override of the autopilots may result in an autopilot disconnect.
3. If FLARE is not armed by approximately 350 feet RA, both A/Ps automatically disengage.
4. ILS Beam Anomaly/Ground Station Failure Detection /invalid ILS signal.
   (FCOM 4.20.17)

Question 18

F/D pitch commands during go around.

Answer 18

F/D pitch commands 15 degrees nose up until reaching programmed rate of climb. F/D pitch then commands target airspeed for each flap setting based on maximum takeoff weight calculations.
(FCOM 4.20.23)

Question 19

During a manual go around, engaging an A/P in CMD automatically engages the A/P in what mode?

Answer 19

Engaging an A/P in CMD automatically engages the A/P and FDs in LVL CHG for pitch.
(FCOM 4.20.25)

Question 20

TO/GA to LNAV - at which altitude during go around the LNAV will engage?

Answer 20

During autoland operations with FLARE arm or FLARE engage displayed then LNAV will engage when the airplane is above 400 feet.
During an approach without FLARE arm or FLARE engage displayed,LNAV mode will engage when the airplane is above 50 feet.
(FCOM 4.20.27)

Question 21

What is the the FD guidance in case of windshear during takeoff or go around?

Answer 21

The F/D pitch command bar provides commands to maintain the target speed until vertical speed decreases to approximately +600 fpm.
At this point, the F/D pitch bar commands a 15 degree nose–up pitch attitude.
If vertical speed continues to decrease, the F/D continues to command a 15 degree pitch attitude until a speed of approximately stick shaker is reached. It then commands pitch attitudes which result in intermittent activation of the stick shaker.
(FCOM 4.20.30)

Question 22

During a manual go-around, when pressing CMD above 400’, what will be the AP modes?

Answer 22

LVL CHG and HDG SEL.

Airspeed window will open and we will need to adjust the speed manually for flaps retraction.