B737 CBT Auto Flight System

[Music] this lesson introduces the 737 automatic flight or auto flight system the auto flight system can reduce crew workload the automatic flight system includes the autopilot flight director system or afds and the auto throttle you control the autoflight system with the mcp and the cdu the cdu controls and shows data from the fmc you use the cdu to select thrust limits target air speeds and flight routes for the auto throttle and afdf to follow the flight mode enunciation and the autopilot and auto throttle disengage lights show the status of the afds the mode control panel

sends data to the two flight control computers or fcc's the fcc's calculate thrust pitch and roll commands for the other auto flight system components one of the fcc's is specified as the master fcc autopilot and flight director status control which fcc is the master while each fcc continues to calculate thrust pitch and roll commands the master fcc usually positions command bars for the captains and first officers flight directors the fccs are called fcca and fccb for autopilot functions fcca controls autopilot a and fccb controls autopilot b for flight director functions the fcc's position command bars

for you to follow are the attitude direction indicators the auto throttle adjusts the thrust levers with commands from the fcc the fccs use sensor data from other systems for their calculations pilot input is necessary for all auto flight system modes that use the navigation radios or the fmc there are different levels of automation possible with the autoflight system the lowest level occurs when you operate the flight directors the airplane is flown manually but the flight director supplies pitch and roll command bars a higher level of automation adds the auto throttle to control thrust and the

autopilot to control pitch and roll the highest level of automation adds the fmc to navigate as the level of automation increases the crew workload decreases you the pilots have control of the autoflight system you tell it what to do you can use all some or none of its function you change most autoflight system modes with the mode select switches change in mode changes the fcc's calculations the mode select switches change the way the fcc's calculate thrust commands pitch commands roll commands or a mixture of thrust pitch and roll commands in these examples fcca is the

master fcc push the heading select switch and look at how the fccs operate the fcc's calculate role commands for the heading select mode the master fcc sends the commands to the flight directors and the autopilot now push the level change switch the fcc's calculate thrust and pitch commands for the level change mode and roll commands for the heading select mode now push the approach switch the fcc's calculate thrust pitch and roll commands for the approach mode when you select the approach mode the other modes are no longer active the flight mode enunciation or fma shows

autoflight system status in four fields above the attitude indicators the fields show data about the auto throttle the pitch mode the roll mode and the afds status now let's look at the operation of the flight director autopilot and auto throttle to show the flight director bars the flight director switch must be on move the captain's flight director switch to fd when the flight director switch is an fd the afds flight mode enunciation shows the status fd but the attitude indicator does not show the flight director bars until you select a mode or modes that use

pitch and roll commands new auto flight modes are shown with the box for 10 seconds if the mode select switch is illuminated you can push the switch again to deselect that mode flight director bars are removed when the flight director switch is off move the flight director switches to fd make sure the flight mode enunciation shows fd in the afds status field push the heading select mode select switch to engage a roll mode push the altitude hold mode select switch to engage a pitch mode notice the flight mode enunciations for auto throttle pitch roll and

afds status the fd enunciation shows that the flight directors are on push one of the autopilot engage switches to engage the autopilot you can only engage one autopilot at a time after you push an autopilot engaged switch make sure the afds status enunciation is correct the command enunciation is now shown when you engage in autopilot the autopilot engages in the modes that are active in this example the autopilot engages in altitude hold and heading select you can engage the autopilot in command or control wheel steering shown as cws in command the autopilot uses flight control

computer commands to control airplane pitch and roll in control wheel steering the autopilot uses control wheel inputs to change pitch and roll now push the autopilot a control wheel steering switch control wheel steering pitch and control wheel steering roll replace command the flight director bars are not removed because the fcc's continue to calculate pitch and roll commands for the flight director the control wheel commands all cws maneuvers when the control wheel is released the autopilot holds the airplane's attitude if the autopilot is in a cws mode and you release the control wheel when the bank

angle is less than six degrees the autopilot commands wings level there are three ways to disengage the autopilot usually you push the autopilot disengaged switch on the outboard hand grip of the control wheel you can also push the autopilot engage switch a second time or pull down the autopilot disengage bar the autopilot disengage bar stays in the down position with a yellow stripe in view the bar must be in the up position before you can engage the autopilot again move the autopilot disengage bar to the up position when the autopilot disengages the autopilot engage switch

light extinguishes the autopilot status enunciation changes the autopilot disengage light flashes [Music] and you hear the warning sound to disengage and autopilot you must select a disengage control and then cancel the warning [Music] the warning can be cancelled with a second push of the autopilot disengage switch or push the autopilot disengage light push the autopilot disengage switch to disengage the autopilot [Music] cancel the warning to engage the auto throttle the auto throttle arm switch must be in the arm position and an auto throttle mode must be selected move the auto throttle arm switch to arm

the auto throttle arm light shows the system is armed and the flight mode enunciation shows the auto throttle status but the auto throttle does not engage because there is not an active auto throttle mode push the speed switch to engage the auto throttle the auto throttle is now engaged and controls thrust there are two ways to disengage the auto throttle usually you push one of the auto throttle disengage switches on the thrust levers when the auto throttle is disengaged the auto throttle arm switch moves to off the auto throttle indicator light extinguishes the speed switch

light extinguishes the flight mode enunciation changes and the auto throttle disengage light flashes push the auto throttle disengage switch a second time or push the auto throttle disengage light to cancel the warning the auto throttle also disengages if the auto throttle arm switch is moved to off now disengage the auto throttle cancel the warning the component that provides pitch and roll commands to the flight directors touch the component that provides pitch and roll commands to the v autopilot touch the component that lets pilots input heading and altitude data to the fcc's touch the component that

lets the pilot select thrust limits target air speeds and flight routes for the afds to follow touch the area that shows afds or autopilot flight director system status data touch the area that shows pitch mode data touch the area that shows roll mode data touch the area that shows auto throttle status data [Music] touch the autopilot disengage light to cancel the warning touch the auto throttle disengage light to cancel the warning turn on the flight directors engage heading select engage and autopilot in command disengage the autopilot cancel the auto cancel the autopilot disengage warning arm

the auto throttle engage the auto throttle in speed mode disengage the auto throttle cancel the warning which items must be true for the attitude indicators to show flight director command bars touch yes or no for each item and then touch done when you are finished the flight director switch must be in fd with pitch and roll modes engaged to show the flight director command bars auto flight roll modes control airplane heading and the path the airplane flies over the earth you select roll modes with these switches on the mcp the roll modes are heading select

vorloke and lnav you control the roll mode with the mcp with the navigation radios and with the fmc the flight mode enunciation shows the roll mode if an autopilot is engaged in command but no role mode is engaged autopilot uses the default mode cws role to change the default condition you must select a role mode in this example the fma shows command and cws role push heading select to engage a role mode the default role mode is replaced by heading select the green box tells you that this is a new mode the bank angle selector

is the control behind the heading selector the selector sets the maximum bank angle between 10 degrees and 30 degrees in five degree increments here a 25 degree bank angle limit is selected the bank angle selector controls the maximum bank angle for only the heading select mode and vor part of the vorloke mode in lnav and in the localizer part of vorloke bank limits are not changed by the bank angle selector turn the bank angle selector to change the maximum bank to 30 degrees the bank angle limit is now set to 30 degrees this limit applies

only to the heading select mode and the vor part of the vorloke mode the heading select mode is used to turn the airplane to the heading set in the heading display window on the mcp when heading select is first engaged the airplane turns in the shortest direction to the new heading the fma shows that heading select is engaged when the turn is complete the airplane holds the new heading if heading select is already engaged and you set a new heading the airplane turns the same direction as you turn the heading selector if heading select is

used to intercept a radio navigation course or an l-nav route it disengages when the course or route is captured four loke and elnav are discussed later to turn the airplane with heading select set the new heading in the heading display window here turn the heading selector to set a heading of 135 push the heading select switch look at the fma to see that heading select is engaged the green letters show that heading select is engaged and the green box tells you that this is a new mode the airplane starts to turn immediately when the turn

is completed the airplane rolls wings level and holds the 135 heading the vorloke mode can intercept and follow a vor radial or localizer course the course selector sets the new course the navigation radios send deviation and course data the fcc's calculate rule commands to intercept and follow the course and the autopilot obeys the role commands if autopilot a is engaged the captain's course selector and the number one navigation receiver send vor or localizer navigation data to fcca if autopilot b is engaged the first officer's course selector and number two navigation receiver send vor or localizer

navigation data to fccb to use vorloke tune the navigation radio frequency in the standby window and then transfer the frequency to the active window identify the navigation source turn the course selector to set a course of 324 degrees in this example the b autopilot is engaged so the first officer's course selector is used usually the two course selectors are set to the same course in this example the captain's course selector was set for you now push the vorloke switch look at the flight mode annunciation vorloke in the small white letters below heading select shows that

vorloke is armed and that heading select stays engaged at course intercept vorloke replaces heading select as the engaged mode and the airplane turns to follow the course usually the heading is set to match the inbound course elnav follows the lateral route programmed into the fmc if the airplane is more than three miles from the active route lnav engages only if the airplane is on a heading that intercepts the active route for the active waypoint and an intercept angle less than 90 degrees when you push the lnf switch and the airplane heading is satisfactory the auto

flight system intercepts and follows the active route if the airplane is within three miles of an active route l-nav can engage from all airplane headings in this example the airplane is more than three miles from the active route set an intercept heading that intercepts the route before the active waypoint and at an intercept angle of less than 90 degrees push lnf fma shows the auto flight system engaged in lnf the auto flight system turns the airplane and follows the active route after the airplane intercepts the active route the autopilot is engaged in command a and

the fma shows a default role mode cws role engage heading select to replace the default roll mode the default roll mode is replaced by heading select change the bank angle limit from 25 degrees to 15 degrees it is the end of a flight and you plan to land on runway zero nine atc changes the runway and tells you to take vectors to runway one eight use heading select to fly a heading of zero zero zero atc now tells you to turn base for runway one eight set a heading of zero nine zero the airplane turns

in the same direction the heading selector was turned and flies the new heading in this example you will use heading select and vorloke to capture and follow a vor radio atc clears you to intercept and fly the santa monica 261 radial inbound tune the navigation radio frequency use identify the navigation radio station set the course selector set the first officer's course selector to the inbound course of 081 degrees now engage vorloke look at the flight mode enunciation for loc in the small white letters below heading select shows that vorloke is armed and that heading select

stays engaged the course intercept vorloke replaces heading select as the engaged mode and the airplane turns to follow the course usually the heading is set to the inbound course set the new heading this example the airplane is more than three miles from the active route set an intercept heading that lets lnav engage if the airplane is more than three miles from the active route lnav engages only if the airplane is on a heading that intercepts the active route before the active waypoint add an intercept angle less than 90 degrees engage lnav the fma shows the

autoflight system engaged in lnf the autoflight system will turn and follow the active route after the airplane intercepts the active route auto flight pitch modes control climbs enroute crews the sets and supply vertical guidance and commands for approaches and automatic landings the autoflight system pitch modes are shown here toga gs and flare are discussed in a different lesson you select pitch modes with these switches on the mcp you control the pitch modes with the mcp and with the cdu when fcca is the master fcc the autoflight system uses data from the captain's barometric altimeter when

fccb is the master the first officer's altimeter is used the flight mode enunciation shows auto throttle status and pitch mode auto flight pitch modes automatically engage in auto throttle mode if the auto throttle is armed the n1 auto throttle mode tells the auto throttle to set thrust at the active n1 limit and keep it there speed is controlled by changes and the airplane's pitch the fmc normally supplies the auto throttle with the n1 limit here auto is active and the fmc automatically sets the n1 limit for the related phase of flight when mcp speed shows

in the auto throttle status field the auto throttle controls the thrust to hold the speed set in the ias mock display window when mcp speed shows in the pitch mode field the autopilot controls pitch to maintain the set speed shows when the auto throttle reduces thrust to idle when the thrust is at idle the enunciation is replaced with arm arm tells you the auto throttle is armed but it does not control thrust when arm is shown you can move the thrust levers as if the auto throttle was disengaged if you manually move the thrust levers

when the auto throttle mode is in one or the auto throttle returns to the target thrust when you release the levers you can find yourself in a fight with the auto throttle above flight level two six zero the ias mock display automatically changes to a mach number in the window below flight level 260 the speed is usually in knots push the changeover switch to change the ias mock display window from mock to knots the mcp speed is now in knots the auto flight system pitch modes level off the airplane at the altitude set on the

mcp when v-nev is the pitch mode the airplane usually levels off at the fmc altitude but if the mcp altitude is between the airplane and the fmc altitude the airplane stops at the mcp altitude the auto flight system also alerts pilots to level offs and altitude deviations in this example the airplane is in a descent to a new mcp altitude when the airplane is near the mcp altitude you hear the altitude alert tone see a box around the current altitude and see an altitude alert box above each altimeter when the airplane is near the mcp

altitude the altitude alert boxes extinguish as the airplane levels off the fma changes to altitude hold the altitude alert operates the same in climb in level flight at the mcp altitude if you climb or descend too much you will hear the altitude alert tone the current altitude box changes color to amber and starts to flash the current altitude box flashes until the altitude error is corrected or until the error is more than the alert limit or until a new altitude is set in the mcp altitude display if an autopilot is engaged in command but no

pitch mode is engaged the autopilot uses the default mode cws pitch to change the default condition you must select a pitch mode push altitude hold to engage a pitch mode the default pitch mode is replaced by altitude hold you use the level change mode to climb or descend to the altitude set in the altitude display window in a level change climb the auto throttle uses the maximum thrust thrust is set to the active n1 limit and n1 shows in the auto throttle field of the fma in a level change descent the auto throttle uses the

minimum thrust because it uses the active n1 limit thrust or idle thrust level change is best used for large altitude changes in this example atc clears you to climb to flight level 350 first set the new target altitude push the level change switch to engage level change the airplane climbs to the new mcp altitude the auto throttle status field of the fma shows n1 and the pitch mode field shows mcp speed when the airplane reaches flight level 350 it automatically levels off the altitude acquire and altitude hold modes are discussed later the vertical speed mode

also changes the airplane's altitude to the altitude set in the mcp altitude window with the vertical speed mode you set the rate of vertical change with the vertical speed thumb wheel and display the vertical speed mode usually causes small changes to thrust and the airplane's pitch attitude because of these small changes the vertical speed mode is best used for small altitude changes you can engage vertical speed in two ways if the airplane is in altitude hold set the mcp altitude display window to a new altitude set a new mcp altitude of 8 000 feet vs

in small white letters tells you that the vertical speed mode is armed to engage the mode you select a target vertical speed with the vertical speed thumb wheel set a vertical speed of minus 500 feet per minute the large green letters on the fma show that vertical speed is engaged the short magenta lines on the vertical speed indicator show the selected vertical speed the vertical speed mode automatically engages mcp speed for the auto throttle in this example mcp speed was engaged while the auto flight system was an altitude hold so there was no change in

the auto throttle mode you can use the vertical speed thumb wheel to set the vertical speed for a climb or descent move the thumb wheel down to set a positive vertical speed and climb an arrow and label show the correct direction to move the thumb wheel to descend move the thumb wheel up to set a negative vertical speed if you want to descend but accidentally set a positive vertical speed the airplane climbs because the airplane moves away from the mcp altitude there is no automatic level off if you are already in a climb or descent

you can push the vertical speed switch to engage vertical speed the airplane's vertical speed shows on the mcp the pitch field of the fma shows vertical speed engaged to change the vertical speed move the thumb wheel set a vertical speed of plus 500 feet per minute the climb continues at 500 feet per minute the auto flight system uses altitude acquire and altitude hold to automatically level off the airplane the airplane starts to level off before the mcp altitude altitude acquire replaces vertical speed as the pitch mode enunciation the point at which altitude acquire engages is

calculated from the climb rate of the airplane when the level off is complete altitude hold replaces altitude acquire when altitude acquire or altitude hold engage as pitch modes and the auto throttle is armed the auto throttle engages in mcp speed automatic level offs after descent are the same you can also use the altitude hold switch to stop a climb or descent if you engage altitude hold when the airplane is at an altitude other than the mcp altitude the airplane levels off at the altitude where the altitude hold switch was pushed the level off does not

occur immediately the airplane momentarily descends below the altitude in a level off from a descent and momentarily climbs above the altitude in a level off from a climb in this example the airplane is in the descent to twelve thousand feet use the altitude hold switch to stop the descent the altitude hold switch was pushed at thirteen thousand four hundred feet the airplane descends below 13 400 feet during the level off but comes back to the altitude where altitude hold was pushed altitude hold replaces the v-nav path enunciation in the pitch field of the fma the

auto throttle status field is now mcp speed after altitude hold engages the afds holds the uncorrected barometric altitude the airplane was at when the mode engaged later changes in altimeter barometric setting do not make the airplane climb or descend to follow the new indicated altitudes when vnav engages the fmc commands pitch and auto throttle modes to fly the vertical path shown on the cdus the profile includes climb cruise descent and speeds it can also include waypoint altitude constraints to use vnav the autoflight system must have an fmc path to follow v-nav speed holds the fmc

target speed this speed is shown by the airspeed cursor and on the cdu climb or descent pages v-nav path uses pitch commands to follow the fmc altitude or descent path if the airplane climbs in vnav the auto throttle sets the fmc supply climb thrust the autopilot maintains the fmc air speed with pitch notice the mcp ias mock display because the fmc controls the target speed this window is blank in cruise the auto throttle maintains the fmc target speed and the autopilot maintains the fmc altitude if you select a lower mcp altitude the afds arms to

automatically start descent when the airplane reaches the top of descent waypoint in a v-nav speed descent the auto throttle sets the thrust to idle and the autopilot holds the fmc target speed in a v nav path descent the autopilot commands the airplane to follow the fmc vertical path the auto throttle holds idle but can command the fmc speed mode if ground speed is too slow to follow the fmc vertical path in this example the fmc route has a cruise altitude of flight level 350 atc tells you to climb and maintain fifteen thousand feet set fifteen

thousand in the altitude push the altitude intervention switch the fma shows you that vnav speed is engaged as the pitch mode and that n1 is the auto throttle mode at 15 000 feet the airplane levels off because you captured an mcp altitude atc now clears you to flight level 350 set the new mcp altitude and push the altitude intervention switch the airplane again climbs in v-nav speed at flight level 3-5-0 the airplane again levels off the fma changes to fmc speed and nav path the airplane can automatically follow the descent path if you have set

the mcp to a lower altitude before you pass the top of descent to help you the cdu scratch pad message reset mcp altitude is shown set a lower altitude of the mcp the airplane descends in v nav path the auto throttle sets the thrust to idle if the winds change the ground speed until it is too slow to follow the fmc path the auto throttle adds thrust to follow the descent path if winds change the ground speed until it is too fast to follow the fmc path the auto flight system pitches down to follow the

path and the cdu scratch pad shows the message drag required if the air speed increases to more than 10 knots above the fmc target speed if atc tells you to change airspeed during vnav flight it can be difficult to do so quickly in vnav modes the speed targets come from the fmc the ias mock window is blank and you cannot change the speed with the mcp except by using vnav speed intervention which will be discussed in a different lesson to quickly change speeds engage a different pitch mode and use the mcp speed selector to set

the new target speed for level flight vnev legs engage altitude hold when altitude hold engages the ias mock window changes from blank to the current speed set the new target speed for vnav climbs or descents engage vertical speed or level change and set the new speed you can also make air speed changes in v-nav flight with speed intervention speed intervention is discussed in another lesson the airplane flies in v nav the auto flight system will obey speed and altitude constraints attached to the flight plan waypoints this is a powerful feature of vnav and can make

arrivals and departures easier to navigate but if atc asks you to delete an altitude constraint or change in airspeed it can mean that you have to program the fmc when you should be looking for traffic you can use speed and altitude intervention to make these changes speed and altitude intervention work only when vnav is engaged in vnav the mcp ias mock display is blank and you cannot change the speed with the mcp speed selector when you push the speed intervention switch the ias mock display window will open to the current fmc target speed the target

airspeed line of the cdu shows that the mcp controls the speed you can now change the speed using the mcp speed selector the target speed is now 0.78 mach if you push speed intervention again the ias mock window blanks and control of the target speed returns to the fmc you are flying the klax loop departure the fmc shows altitude constraints at kegs and coupe the altitude constraint of thirteen thousand feet for kegs is in the mcp altitude window atc tells you that the constraint at kegs is deleted because there is still a constraint at coop

enter fifteen thousand feet into the mcp altitude window when you push altitude intervention the constraint at kegs erases if the mcp altitude is above the constraint altitude each push of altitude intervention removes one more altitude constraint the airplane levels at 15 000 feet to obey the fmc altitude constraint at coop atc now clears you to your planned cruise altitude of flight level 350. if the airplane is at an fmc altitude constraint altitude intervention lets the airplane resume the v nav climb here the climb will continue to the flight level three 350 cruise altitude atc clears

you to a new cruise altitude of flight level 390. set the mcp altitude to 39 000 and push altitude intervention if the mcp altitude is above the fmc cruise altitude the fmc cruise altitude increases to the higher mcp altitude here you are in a v nav path cruise atc now clears you to flight level four one zero set 41 000 in the mcp altitude window and push altitude intervention the fmc cruise altitude changes to match the mcp and the airplane begins a cruise climb to flight level four one zero if you set the mcp altitude

below the current fmc cruise altitude and push altitude intervention the airplane begins an early descent you cannot set a lower cruise altitude with altitude intervention in this example the airplane flies the red eye arrival to klax there are many altitude constraints on this arrival in the descent to civet the mcp altitude window shows 14 000 atc removes the altitude constraint at civit set the next lower altitude constraint and push altitude intervention the constraint at civit erases atc now removes the constraints at bindi bassett and downey set the mcp altitude window to cross santa monica at

eight thousand feet if all altitude constraints are removed from a v nav path descent the fmc automatically changes to a v-nav speed descent atc clears you to 6 000 feet and removes the altitude constraint at santa monica who are five miles behind slower traffic atc tells you to slow to 250 knots for separation use the afds to slow the airplane use the speed selector on the mcp to set the new speed you are in level flight at nine thousand feet autopilot a is engaged but no pitch mode is selected engage altitude hold atc has cleared

you to descend and maintain 8500 feet use the afds to descend you are in a descent to 8 000 feet when atc tells you to hold your present altitude use the afds to stop your descent the airplane levels off at eight thousand six hundred feet reset the mcp to stop the altitude alert atc clears you to descend to ten thousand feet use the level change mode atc tells you to reduce your descent rate to 500 feet per minute use the afds to set a 500 feet per minute descent atc clears you to descend to 8

000 feet use the vertical speed mode to descend atc tells you to maintain your altitude for traffic use the afds to level off immediately the fmc has a route with a cruise altitude of flight level 330 atc clears you to climb to flight level 330 use vnav to climb to the cruise altitude you are in vnav cruise flight an atc tells you to slow to 0.72 mach for separation use speed intervention to slow the airplane you are in v nav cruise flight and atc clears you to climb to flight level 370 use altitude intervention to

change the cruise altitude you are on the sadie arrival to klax when atc tells you to descend to 10 000 feet and delete the altitude constraint at simon use altitude intervention to remove the constraint the auto flight system can assist you at takeoff it supplies flight director guidance and automatic thrust control the autopilot can be engaged only after takeoff the flight director supplies pitch and roll commands during takeoff the flight director gives roll commands for wings level and pitch commands to fly the climb profile you use the auto throttle to set takeoff thrust and to

reduce thrust to climb thrust after takeoff to engage the takeoff mode the two flight directors must be on the flight director that is turned on first makes the related fcc the master fcc and illuminates a master flight director indicator the master fcc sets the modes for the fcc's and controls enunciations on the fmas turn on the flight director for the pilot flying first you use the mcp to set the auto flight system for takeoff during the pre-flight you set v2 in the ias mock window to use the auto throttle for takeoff you must set the

auto throttle switch to arm the auto throttle indicator light illuminates and the fma shows that the auto throttle is armed the thrust mode display or tmd shows the active n1 limit to shows that the auto throttle limit is take off thrust to engage the takeoff mode advance the thrust levers to approximately forty percent and one and let the engines stabilize this helps make sure there is a symmetrical thrust increase to the takeoff in one next push a toga switch the n1 and toga enunciations show on the fma the flight director command bars show a 10

degree nose down pitch and the auto throttle advances the thrust to the n1 limit at 60 knots the flight director command bars move to show a 15 degree nose up pitch this shows the initial target attitude when the airplane rotates after vr it is not a rotation command at 84 knots the auto throttle mode changes to thrust hold in thrust hold power is removed from the auto throttle this protects against thrust lever movement if a system fault occurs as with arm thrust hold let you manually move the thrust levers without a subsequent correction from the

auto throttle check if takeoff thrust is set if takeoff thrust is not set before the auto throttle mode switches to thrust hold you must set the thrust manually in this example you must set the thrust manually during initial climb out the flight director command bars show the fixed 15 degree pitch target attitude once sufficient climb rate is acquired the pitch bar commands mcp speed v2 plus 20 knots at 400 feet radio altitude engage a role mode such as lnav heading select or vor localizer in this example heading select is selected when you push toga at

eight hundred feet radio altitude the auto throttle mode changes from thrust hold to arm when you reach the flap retraction altitude and you push the n1 switch on the mcp the thrust is reduced to climb thrust the thrust reduction altitude can be set on page two of the fmc takeoff pages climb power will automatically be set at that altitude this will be discussed in a different lesson for this example we will manually set climb thrust push the n1 switch now the auto throttle field of the fma now shows n1 and the tmd and reference n1

bugs show the new active n1 limit climb when you increase the mcp speed to retract the flaps the flight director no longer commands a speed of v2 plus 20 knots pitch is now set to maintain the mcp speed if you engage an autopilot while in takeoff mode the pitch mode automatically engages in level change the pitch field of the fma shows mcp speed and the auto throttle field shows n1 the mcp ias mock window and airspeed cursor change to v2 plus 20 knots and the roll mode engages in heading select unless a different role mode

was selected after takeoff the autoflight system goes out of the takeoff mode when an autopilot is engaged or a pitch mode is engaged the autoflight system approach modes can be used for flight director only or single and dual channel autopilot approaches and can also control automatic landings the go around modes show flight director command bars and can supply commands to the autopilot to fly a dual autopilot approach you must arm the auto flight system for approach verify the inbound course is set on the mcp and the localizer frequency is tuned on the navigation radios when

the airplane is on a localizer intercept heading check to see if the localizer frequency is identified and that the glide slope and localizer pointers are in view then push the approach switch verify that the approach mode is armed with the fma the pitch field shows glide slope and the roll field shows vorloke in small white letters next push command on the second autopilot this arms the second autopilot but does not engage it borloke changes from armed to active on the fma after localizer capture after localizer capture set the heading to match the inbound course the

auto flight status field annunciation shows single channel this tells you that only one autopilot is engaged at glide slope capture glide slope changes from from an armed to an active mode the tmd displays go around as the active n1 thrust limit and you set the missed approach altitude on the mcp at glideslope capture the light in the approach switch goes dark you cannot disengage the approach mode with the second push of the approach switch to leave the approach mode after localizer and glideslope capture you must push toga or disengage the autopilot and turn off the

flight directors or retune a vhf navigation receiver after glide slope and localizer capture the second autopilot engages when the airplane is below 1500 feet radio altitude the single channel enunciation is removed and flare armed is enunciated in the pitch field now the autopilot go around mode is also armed but is not enunciated for a dual autopilot approach you must select the second autopilot above 800 feet radio altitude below 800 feet radio altitude you cannot engage the second autopilot at 400 feet radio altitude the autopilots automatically add an additional amount of stabilizer nose up trim if

the autopilots disengage after this occurs you must hold forward control pressure on the control wheel until you can manually remove the trim if flare is not armed by 350 feet radio altitude the autopilots automatically disengage the flare maneuver starts at 50 feet radio altitude the autopilot trims the airplane in the flare the fma pitch field changes to flare and the flight director command bars are removed the auto throttle reduces thrust to idle below 27 feet radio altitude and the fma shows the auto throttle automatically disengages after touchdown but you must manually disengage the autopilot this

shows the steps for a dual autopilot approach a single autopilot approach is the same as the dual autopilot approach but the second autopilot is not engaged after approach is selected the single channel enunciation shows for the full approach flare is not enunciated and the flare and automatic touchdown capability are not available and an autopilot go around is not available with a single channel autopilot approach you must flare and land manually the autopilot must be disconnected before you reach 50 feet radio altitude go around mode is engaged when you push one of the two toga switches

on the thrust levers two autopilots must be engaged for an autopilot go around if one autopilot is engaged only the flight director go around is available when you push a toga switch for an autopilot go around the auto throttle engages in go around the thrust increases to a reduced go around and one that produces one thousand to two thousand feet per minute rate of climb the pitch mode engages in toga and a target pitch of 15 degrees is commanded until the climb rate is between 1000 and 2000 feet per minute at the target climb rate

the autopilot changes pitch to hold the maneuvering speed for the set flap position based on maximum takeoff weight calculations the roll command holds the ground track the fma is blank in the role field the ias mock window is blank and the airspeed cursor shows the maneuvering speed for the current set flap position based on maximum takeoff weight calculations as you retract the flaps the airspeed cursor moves to the maneuvering speed for the new flap position based on maximum takeoff weight calculations the airplane will automatically accelerate to the new target speed as the flaps are retracted

after the auto throttle is at the reduced go around thrust a second push of the toga switch increases the thrust to the full go around thrust the autopilot increases the pitch to hold the maneuvering speed for the set flap position above 400 feet radio altitude you can engage a roll mode here engage heading select if you keep the auto flight system in go around mode and you are close to the missed approach altitude the autopilot changes to altitude acquire and captures the missed approach altitude when the go-around mode disengages the last autopilot engaged in command

also disengages and the mcp speed window is no longer blank the mcp speed window shows the target speed that was active when the autopilot exited the go around mode the flight director go around can be used on single autopilot approaches on dual autopilot approaches before flare is armed and on a manual approach you can use the flight director go around when you are below two thousand feet radio altitude if you start a go around when the flight directors are off the command bar will automatically pop up to engage the flight director go around push a

toga switch [Music] unless flare is armed on a dual autopilot approach all autopilots disengage when you push toga the flight director command bars show target pitch and roll attitudes to maintain track and flat maneuvering speed but the pilot must control pitch and roll if you engage in autopilot during a flight director go around the pitch mode engages in level change and the role mode engages in heading select unless a different role mode was engaged first are the flight directors for takeoff in this example the captain is the pilot flying as you prepare for a takeoff

the cdu shows a takeoff v2 speed of 135 knots set the v2 speed for the auto flight system arm the auto throttle for takeoff airplane is aligned with the takeoff runway set the thrust to start the takeoff gauge the toga mode at 400 feet radio altitude a different role mode can be selected at the flap retraction altitude select climb thrust in this example we will manually set climb thrust push n1 on the mcp increase speed to the flaps up maneuvering speed the autopilot is certified to be engaged above four hundred feet in this example we

will engage the autopilot at one thousand feet you are on a radar vector to intercept the localizer use the data shown to fly a single autopilot approach first set the navigation radio and the course selector for the captain set the course selectors to the inbound set the navigation radio and the course selector for the first officer arm the approach mode on a radar vector to intercept the localizer and plan to fly a dual autopilot approach the captain's navigation radio and course are set set the first officer's navigation radio and course arm the approach mode airplane

is ready to fly a dual autopilot approach you are on a dual autopilot approach at minimums you do not see the runway go around you are now above 400 feet radio altitude you are on a single autopilot approach but atc tells you to go around autopilot has disengaged you are now above 400 feet radio altitude you are flying a manual approach with the flight directors off late in the approach atc tells you to go around a manual flight director only go around pops up if the stabilizer out of trim light illuminates the stabilizer has not

been trimmed correctly by the autopilot trim system when the stabilizer out of trim light illuminates hold the controls tightly and disengage the autopilot disengage the auto throttles use electric or manual trim to correct the stabilizer position if the stabilizer is out of trim below 800 feet on a dual autopilot approach the autopilot warning light illuminates steady red this warns the pilot of possible control field changes if the autopilot is disengaged for the landing other problems with the auto flight and stabilizer trim systems can occur on a dual auto pilot go around you saw before that

two autopilots are only used for approach and go around all other pitch and roll modes use a single autopilot on a dual autopilot approach the autopilot adds nose up trim on short final when a missed approach occurs the autopilots start to remove the nose up trim to prepare for single autopilot operation after the trim is removed altitude acquire can engage for level off but during some conditions the autopilots cannot change the trim sufficiently in the time available to let altitude acquire engage the altitude acquire mode is then inhibited this causes the autopilot warning light to

eliminate steady you must disengage the autopilot and manually fly the airplane to level off at the specified altitude when the autopilot is disengaged there can be unwanted nose up trim remaining altitude acquire inhibit can occur under these conditions low missed approach altitude full go around thrust and light weight the auto flight systems do many self-checks to make sure the guidance commands are valid failure of these internal monitors usually cause the autopilots to disengage when two autopilots are engaged special requirements are imposed on the auto flight systems the most important requirements are that inputs to the

autopilots agree and that guidance commands from the autopilots agree if the inputs are different or the autopilots disagree the autopilots are disengaged by performance monitors but this rule is applied differently for the radio altimeters when the airplane descends through 1500 feet above ground level the monitors check for two radio altimeter signals if there are two signals the monitors let the second autopilot engage and the flare mode arms if a radio altimeter fails after flare is armed the autopilots ignore the failure as the airplane goes through the flare altitude one autopilot tries to flare and the

other cannot this causes two autopilots to disengage and puts the airplane in your control at a very important and unexpected time to prevent surprises cross-check the flight instruments at 500 feet be sure to check the two radio altimeters for normal operation the autopilot also helps the pilot check for flare armed as the airplane passes through 380 feet the performance monitors check to see if flare is armed if flare is not armed the auto pilots disengage [Music] my [Music] now [Music]