Automatic Flight - Operations Show Schematic Only

Amendment: Autolands Allowed with Engine Inoperative Prior to Landing Flaps.

Takeoff and Climb Profile

On some installations CLB thrust is automatically set when another pitch or A/T mode is selected.

Takeoff is a flight director only function and can only be engaged on the ground. The autopilot is not used during the takeoff roll but may be engaged after lift-off.

During pre-flight:

On takeoff, prior to 80 knots IAS:

During takeoff, prior to lift-off:

At lift-off:

After lift-off:

Note: Autopilot elevator authority during a single autopilot operation is limited to reduce the effects of an autopilot malfunction. During altitude capture, there may be insufficient elevator authority and stabilizer trim rate to counteract pitch down, caused by the combination of thrust reduction, flap retraction and aft cg.

Note: An altitude capture from a climb that includes a significant airspeed increase or thrust reduction may result in the autopilot descending away from the selected altitude in an attempt to increase the airspeed.

Cruise

The autopilot and/or flight director can be used after takeoff to fly a lateral navigation track (LNAV) and a vertical navigation track (VNAV) provided by the FMC. Using LNAV and VNAV ensures the most economical operation.

Other pilot selected control modes are available for guidance:

  • Flight Level Change (FLCH)
  • Heading Select (HDG SEL)
  • Heading Hold (HDG HOLD)
  • Vertical Speed (V/S)
  • Altitude Hold (ALT HOLD)

Approach and Landing

The AFDS provides guidance for single or multiple autopilot precision approaches. Pushing the APP switch arms localizer in the roll mode and glideslope in pitch mode. With any single autopilot engaged, manual arming of one, or both of the remaining two (by selecting them to CMD) is necessary for a multiple autopilot approach.

The AFDS provides guidance for multiple autopilot precision approaches. Pushing the APP switch arms localizer in the roll mode and glideslope in the pitch mode. Also, with an autopilot engaged, the remaining two autopilots automatically arm for a multiple autopilot approach.

Either localizer or glideslope can be captured first.

G/S INHIBIT Glideslope capture is inhibited until the localizer is captured.

Pushing the LOC switch arms the AFDS for localizer tracking. Descent on the localizer can be accomplished using VNAV, FLCH or V/S pitch modes. The localizer mode cannot capture if the intercept angle exceeds 120 degrees. All other non-precision approaches can be flown using LNAV and VNAV modes, or HDG SEL or V/S modes.

Pushing the B/CRS switch in conjunction with the LOC switch will enable localizer back course tracking.

Runway Alignment and Asymmetric Thrust Compensation

AFDS controls the rudder during multiple autopilot ILS approaches to compensate for engine-out asymmetric thrust conditions during an ILS approach.

With [AUTO] LAND 3 or [AUTO] LAND 2 annunciated, autopilot control of the rudder is active.

The runway align sub-mode is operative during multiple autopilot ILS approach. It reduces the crab angle established during crosswind conditions prior to automatic landing. The submode operates as follows:

If the autopilots are disengaged, manually or automatically, in an asymmetric thrust condition with rudder control active, the rudder moves to the trimmed position. The pilot may need to exert rudder pedal force to maintain a smooth transition to manual flying.

Autolands Allowed with Engine Inoperative Prior to Landing Flaps

FCTM Some airplanes have an engine out autoland option activated. This option provides the capability to conduct an automatic approach to Category 3A minimums, with an engine initially inoperative, if the quality of the approach is satisfactory.

Additional engine-out logic is incorporated during runway alignment to ensure the downwind wing is not low at touchdown. If the crosswind is from the same side as the failed engine, then the airplane is crabbed by inducing a sideslip. This assures a wings-level approach. For moderate or strong crosswinds from the opposite side of the failed engine, no sideslip is induced as the failed engine high approach configuration guarantees an upwind wing low touchdown characteristic.

Flare

The flare manoeuvre brings the airplane to a smooth automatic landing touchdown. The flare sub-mode is a multiple autopilot mode, and is not intended for single autopilot or flight director only operation.

During flare:

Note: During an approach with two autopilots engaged [AUTO] LAND 2 and below 330 feet Radio Altitude an increment of nose up trim is automatically applied for flare. If the autopilots are subsequently disengaged in the approach, a forward control column force of 20-30 pounds may be required to counter the automatic trim condition. If an automatic multi-autopilot go-around is performed, the increment of automatic trim is removed.

Note: During an approach with two autopilots engaged [AUTO] LAND 2 and below 100 feet Radio Altitude an increment of nose up trim is automatically applied for flare. If the autopilots are subsequently disengaged in the approach, a forward control column force of 20-30 pounds may be required to counter the automatic trim condition. If an automatic multi-autopilot go-around is performed, the increment of automatic trim is removed.

Rollout

Rollout is a multiple-A/P approach sub-mode and provides runway centerline rollout guidance.

During rollout, autothrottle IDLE mode remains active until the autothrottle disengages. Autothrottle disengagement occurs when either thrust lever is set in reverse thrust position.

When selecting reverse thrust the A/T DISC caution light, AUTOTHROT DISC EICAS message and aural warning will not be activated.

Go-Around

Pushing either GA switch activates a go-around using multiple autopilot, single autopilot or flight director only.

When the F/D switches are not on, pushing either GA switch displays the flight director bars.

Go-around arms and the reference thrust limit changes to GA when:

Arming is not annunciated. GA remains armed until two seconds after five feet Radio Altitude. Pushing either GA switch during this period of the approach engages the GA mode. The mode remains active even if the airplane touches down while executing the go-around.

The GA switches are interlocked with the thrust reversers to prevent go-around mode engagement during Reverse Thrust operation.

Pushing either GA switch:

Note: Autopilot elevator authority during a single autopilot approach is limited to reduce the effects of an autopilot malfunction. If a go-around is initiated during a single autopilot approach, there may be insufficient elevator authority and stabilizer trim rate to counteract pitch up, caused by a rapid application of full go-around thrust. There is sufficient elevator authority to counteract pitch up when the go-around is flown using multiple autopilots, or manually (no autopilot), or when the Autothrottle go-around mode is used to set a 2000 fpm climb rate.

GA level-off:

GA Mode Termination:

Below 400 feet Radio Altitude:

Above 400 feet Radio Altitude:

Note: If the autopilot systems are compensating for an asymmetric thrust condition when they revert to a single autopilot in CMD configuration, the rudder will return to the trimmed position unless the pilot exerts the rudder pedal force required to maintain the rudder position.

Note: On detection of a failure in the first in CMD A/P, the fail sequence logic selects a different channel to be first in CMD. In the case of the R A/P being the first in CMD and failing, the Center A/P will remain engaged at the first pitch or roll mode change following GA.

Windshear Recovery

The AFDS provides windshear recovery guidance by means of the normal go-around pitch and roll modes. With go-around armed, pushing a GA switch commands a pitch-up of 15 degrees or slightly below the Pitch limit Indicator, whichever is lower.

If the autopilot is not engaged at the time go-around is initiated, the pilot must fly the windshear recovery following flight director commands. If the Autothrottle is not armed or engaged, the thrust levers must be advanced manually.

Limit Modes