B 737 NG Ground School. See the aircraft study guide at www.theorycentre.comThe information contained here is for training purposes only. It is of a general nature it isunamended and does not relate to any individual aircraft. The FCOM must be consulted forup to date information on any particular aircraft.
B737-800AUTOPILOT FLIGHT DIRECTOR SYSTEM (AFDS) PART 2It is intended that AFDS Part 1 has been Completedbefore starting this part. This will give betterunderstanding of the following content.
Automatic Flight Takeoff and ClimbTakeoff is a flight director only function of the TO/GA mode. Flightdirector pitch and roll commands are displayed and the autothrottlemaintains takeoff N1 thrust limit as selected from the FMC. Theautopilot may be engaged after takeoff.Both F/Ds must be ON to engage the takeoff mode prior to startingthe takeoff.The F/D takeoff mode is engaged by pushing the TO/GA switch oneither thrust lever. The FMAs display FD as the A/P status, TO/GA asthe pitch mode, and blank or LNAV arm for the roll mode.During takeoff, pushing a TO/GA switch engages the autothrottle inthe N1 mode.The A/T annunciation changes from ARM to N1 and thrust leversadvance toward takeoff thrust.The F/D can also be engaged in the takeoff mode with the F/Dswitches off. If a TO/GA switch is pushed after 80 knots below 2000feet AGL and prior to 150 seconds after lift–off, the F/D commandbars automatically appear for both pilots.
Automatic Flight Takeoff and ClimbDuring takeoff, prior to 60 KIAS:• the pitch command is 10 degrees nose down• the roll command is wings level• the autothrottle is engaged in the N1 mode• thrust levers advance until the engines reach takeoff thrust• the FMAs display N1 for the autothrottle mode, TO/GA for thepitch mode, and blank for the roll mode.Note: It is not recommended to use the nose wheel steering to maintainthe direction when the speed exceeds 30 knots.Push forward the control column slightly to aid in direction control.Keep direction with rudder pedals.At 60 knots, the F/D pitch commands 15 degrees nose up.Observe flight director rises by 60 knots; commanded pitch attitude 15°.Control column release the forward pressure back to center.At 84 knots, the A/T mode annunciates THR HLD.
Automatic Flight Takeoff and ClimbAt LIFT-OFF:• the pitch command continues at 15 degrees until sufficient climbrate is acquired. Pitch then commands MCP speed (normally V2)plus 20 knots• if an engine failure occurs during takeoff, the pitch commandtarget speed is:• V2, if airspeed is below V2• existing speed, if airspeed is between V2 and V2 + 20• V2 + 20, if airspeed is above V2 + 20• the roll command maintains wings level.After LIFT-OFF:• the A/T remains in THR HLD until 800 feet above field elevation.A/T annunciation then changes from THR HLD to ARM
Automatic Flight Takeoff and ClimbAutomatic reduction to climb thrust occurs upon reaching the selectedthrust reduction altitude which is shown on the FMC CDU TAKEOFFREF page 2/2 during preflight, or when the airplane levels off in ALTHOLD or VNAV PTH. Pilot entries can be made to override the defaultvalue. Allowable entries are 800 feet to 9999 feetflight director engaged status is terminated by engaging an autopilot inCMD (CMD replaces FD in A/P status display)• pitch engages in LVL CHG and pitch mode FMA is MCP SPD unlessanother pitch mode has been selected• MCP IAS/Mach display and airspeed cursor change to V2 + 20 knots• roll mode engages in HDG SEL unless another roll mode has beenselected.To terminate the takeoff mode below 400 feet RA, both F/D switchesmust be turned OFF. Above 400 feet RA, selection of another pitchmode or engaging an autopilot will terminate the takeoff mode; otherF/D roll modes can be also selected.
Basic Autopilot ModesTake-Off •Is a Flight Director function ONLY PITCH BAR Commands -10 until 60 knots. Then + 15 until positive rate of climb. Then MCP (V2) + 20 ROLL BAR commands Wings Level.
Push TOGA switch.Both FD ON A/T ArmedLNAV ARMED
Auto Throttle sets thrust to selected limit. Thrust mode shows N1Push TOGA switch.Both FD ON A/T ArmedLNAV ARMED
Auto Throttle sets thrust to selected limit.Push TOGA switch. FD Takeoff mode.Both FD ON A/T Armed Roll bar wings levelLNAV ARMED Pitch Bar - 10
Auto Throttle sets thrust to selected limit. LNAV may be armed before takeoff if; The course to the first waypoint is within 5°of runway headingPush TOGA switch.Both FD ON A/T ArmedLNAV ARMED
At Acceleration HeightSelect N1 on the MCP.Then move the speed bugto UP.
At Acceleration HeightSelect N1 on the MCP.Then move the speed bugto UP.Autopilot to CMD.
At Acceleration HeightSelect N1 on the MCP.Then move the speed bugto UP.Auto Throttle CHANGES toN1 automatically ifVNAV, ALT ACQ or ALTHLD are active pitchmodes.
The autopilot or FD will nowcommand pitch to accelerate theaircraft to the new commandspeed.As long as there is accelerationwhen the trend arrow touches orpasses 1 (The flap 1 minimumspeed) select flap 1.
When flap 1 isselected 1 will beremoved.Again when the trendarrow touches UPselect flap upIf speed restriction isbelow flap UP thenstay at flap 1 until thespeed can beincreased to or aboveflap UP minimumspeed.UP will be removedabove approximately20,000 feet.
At Thrust reduction heightthe Thrust mode changesfrom TO to CLBThere is normally a slightthrust reduction.
First Autopilot into CMD Pitch mode changes from TO/GA to MCP Speed.
First Autopilot into CMD Pitch mode changes from TO/GA to MCP Speed. The MCP window is set to V2 for takeoff. After lift off the FD mode commands V2 + 20. If an auto pilot is engaged into command before the MCP speed is increased MCP IAS/Mach display and airspeed cursor change to V2 + 20 knots. Normal operating procedure is; At acceleration height Select N1. Set flap UP speed then auto pilot to command.
CLIMBING VNAV • A/T maintains FMC N1 limit • AFDS commands pitch to maintain FMC target speed Climb Thrust Limit Speed on ELEVATOR set and HELD Set by FMC
FMC has a default speedrestriction of 250 knots below10,000 feet.When VNAV is engaged below10,000 feet the aircraft willaccelerate to 250 knots.The speed restriction can bechanged or deleted on the CLBpage.If some other speed restriction isin place like maintain maximum220 knots until on route then becareful of VNAV.
CLIMBING Level Change • A/T maintains selected thrust limit thrust • N1 on FMA • AFDS commands pitch for selected MCP airspeed. Climb is initiated by: • selecting a new altitude on the MCP • pushing the LVL CHG switch • setting the desired airspeed on the MCP
CLIMBING Vertical Speed • A/T maintains selected MCP airspeed • AFDS commands pitch to maintain selected vertical speed.In V/S mode. V/S has priority! The A/T can increase thrust only up to thecurrent thrust mode limit. Normally Climb thrust. Speed may decay in a V/Sclimb. At about 1.3 Vs The mode will revert to LVL CHG. The pitch will reduceto maintain minimum speed plus 5 knots. Letter A will flash in speed window.
Vertical Speed Command ModeThe V/S mode commands pitch to hold selected vertical speed andengages A/T in SPEED mode to hold selected airspeed. V/S modehas both an armed and an engaged state.Engaged –• annunciates V/S pitch mode• vertical speed display changes from blank to present vertical speed• desired vertical speeds can be selected with vertical speedthumbwheel.V/S becomes armed if:• pitch mode is ALT HLD at selected MCP altitude and• new MCP altitude is selected (more than 100 feet from currentaltitude).With V/S armed, V/S mode is engaged by moving vertical speedthumbwheel.
V/S mode automatically engages if ALT ACQ mode is engaged and anew MCP altitude is selected which is more than 100 feet differentfrom previously selected altitude.• vertical speeds can be selected which command flight toward oraway from selected altitude.Inhibited if:• ALT HOLD mode is active at selected MCP altitude• glideslope captured in APP mode.Reversion ModesDuring some flight situations, speed control by the AFDS or A/T alonecould be insufficient to prevent exceeding a limit speed. If thisoccurs, AFDS or A/T modes automatically revert to a more effectivecombination. The reversion modes are:• placard limit reversion• minimum airspeed reversion.Mode reversion occurs slightly before reaching the limit speed. Boththe AFDS and A/T have reversion modes which activate according tothe condition causing the reversion.
Minimum Speed ReversionThe AFDS and A/T do not control to a speed which is less thanminimum speed for the current flap configuration. This speed isapproximately 1.3 Vs. Minimum speed, FMC speed, or selectedspeed, whichever is higher, becomes the AFS commanded speed. Ifactual speed becomes equal to or slightly less than the minimumspeed, the underspeed limiting symbol A appears in the MCPIAS/Mach Display, and if operating in the V/S mode, the AFDSreverts to LVL CHG.The AFS commands a speed 5 knots greater than minimum speed.Reaching a speed 5 knots greater than minimum speed reactivatesnormal MCP speed selection control. The AFDS commands nosedown pitch to increase airspeed if the thrust levers are not advanced.When actual speed becomes 5 knots greater than minimumspeed, the underspeed limiting symbol disappears.
The A/P disengages and the F/D command bars retract when in aLVL CHG climb with a command speed equal to minimum speedand a minimum rate of climb cannot be maintained withoutdecelerating.Minimum speed reversion is not available when the A/T is OFF andthe AFDS is in ALT HOLD or after G/S capture.Minimum speed reversion is also not available when in VNAV PTHand flying a level segment.
Cruise FlightAt the FMC Top Of ClimbThe Trust mode changesto CRZ
Cruising Altitude Hold • A/T maintains MCP selected airspeed • AFDS commands pitch to hold MCP altitude or altitude at which Altitude Hold (ALT HLD) switch was pressed.
Automatic Flight En RouteThe autopilot and/or the flight director can be used after takeoffto fly a lateral navigation track (LNAV) and a vertical navigationtrack (VNAV) provided by the FMC.Other roll modes available are:• VOR course (VOR/LOC)• heading select (HDG SEL).Other pitch modes available are:• altitude hold (ALT HOLD)• level change (MCP SPD)• vertical speed (V/S).
Descent VNAV • A/T maintains idle thrust • AFDS commands pitch to maintain FMC airspeed • (VNAV SPD) or FMC path (VNAV PATH) • Level off occurs at the MCP altitude (pitch mode ALT HLD) or (VNAV PATH) whichever occurs first Speed is on ELEVATOR
FMC has a default speed of 240knots below 10,000 feet.This can be changed or deletedon the DES page.During a VNAV descent a smallgreen circle labelled deccel willbe shown at the point ofdeceleration. The pitch attitudewill be reduced to allow for thedeceleration.B737 slows approximately 10knots for every mile track. Allowsufficient room to slow!
Descent Level Change • A/T maintains idle thrust • RETARD Then ARM • AFDS commands pitch for selected MCP airspeed. Descent is initiated by: • selecting a new altitude on the MCP • pushing the LVL CHG switch • setting the desired airspeed on the MCP • LVL CHG is inhibited after glide slope capture
Descent Vertical Speed • A/T maintains selected MCP airspeed • AFDS commands pitch for selected vertical speed.Minimum thrust in flight is flight idle. In V/S descent if thrust is at idle airspeedmay increase. At Vmo/Mmo – 5 knots the V/S mode will revert to LVL CHG
Reversion ModesDuring some flight situations, speed control by the AFDS or A/Talone could be insufficient to prevent exceeding a limit speed. If thisoccurs, AFDS or A/T modes automatically revert to a more effectivecombination. The reversion modes are:• placard limit reversion• minimum airspeed reversion.Mode reversion occurs slightly before reaching the limit speed.Placard Limit ReversionWhen one of the placard limit reversions (gear, flap or Vmo/Mmo) isreached, the overspeed limiting symbol 8 appears in the MCP IAS/Machdisplay and the following occurs:• if the AFDS is engaged but not in speed or CWS mode, and the A/T isarmed but not in speed control, the A/T reverts to SPEED and controlsspeed to slightly below the placard limit• if the AFDS or A/T is in speed control, speed is maintained slightlybelow the placard limit• for VMO/MMO only, if the A/T is engaged in a speed mode and thethrust levers are at idle, the AFDS, if in V/S mode, will automaticallyengage to LVL CHG mode.
AUTO PILOT APPROACH DC BUS 1 DC BUS 2 DC Cross Bus Tie RelayRadio Altimeter 1 Radio Altimeter 2 VHF NAV 1 VHF NAV 2 Autopilot approach •Single autopilot approach; or •Dual autopilot approach & landing
AUTO PILOT APPROACH DC BUS 1 DC BUS 2 DC Cross Bus Tie RelayRadio Altimeter 1 Radio Altimeter 2 VHF NAV 1 VHF NAV 2 Autopilot approach •Single autopilot approach; or •Dual autopilot approach & landing NAV receiver/s tuned to an ILS frequency & course/s set before arming APP
Automatic Flight Approach and LandingThe AFDS provides guidance for single A/P non–precisionapproaches. The VOR/LOC switch arms the AFDS for VOR orlocalizer tracking. Descent may be accomplished usingVNAV, LVL CHG, or V/S. VOR/LOC, LNAV, or HDG SEL maybe used for the roll mode.The AFDS provides guidance for single or dual A/P precisionapproaches. The approach mode arms the AFDS to captureand track the localizer and glideslope.
Approach (APP) Mode Dual A/PsApproach mode allows both A/Ps to be engaged at the same time.Dual A/P operation provides fail–passive operation through landingflare and touchdown or an automatic go–around. During failpassive operation, the flight controls respond to the A/Pcommanding the lesser control movement. If a failure occurs in oneA/P, the failed channel is counteracted by the second channel suchthat both A/Ps disconnect with minimal airplane manoeuvring andwith aural and visual warnings to the pilot.One VHF NAV receiver must be tuned to an ILS frequency beforethe approach mode can be selected. For a dual A/P approach, thesecond VHF NAV receiver must be tuned to the ILS frequency andthe corresponding A/P engaged in CMD prior to 800 feet RA.
Localizer and Glideslope ArmedAfter setting the localizer frequency and course, pushing the APPswitch selects the APP mode. The APP switch illuminates andVOR/LOC and G/S annunciate armed. The APP mode permitsselecting the second A/P to engage in CMD. This arms the secondA/P for automatic engagement after LOC and G/S capture andwhen descent below 1500 RA occurs.The localizer can be intercepted in the HDG SEL, CWS R or LNAVmode.Note Intercepting the localiser is assured from HDG SEL. With anyinaccuracy of navigation the Localiser path may be paralleled inLNAV. Company SOP dictates!
Autopilot ApproachDescending Speed on Thrust .Pitch controlling FMC descent pathLocaliser back course tracking is not available.
Autopilot ApproachDescending Speed on Thrust .Pitch controlling FMC descent pathLocaliser back course tracking is not available.Localiser Antenna switching fromTail to nose occurs whenVOR/LOC is annunciated.ARM or ENGAGED
Autopilot ApproachAt 2,500 Feet.Radio Altitude and Rising Runwayare displayed
Autopilot ApproachAt 2,500 Feet.Radio Altitude and Rising Runwayare displayed Use of Heading Select ensures LOC is intercepted.
Localizer CaptureThe LOC capture point is variable and depends on intercept angleand rate of closure. Capture occurs no later than 1/2 dot. UponLOC capture, VOR/LOC annunciates captured, SINGLE CH isannunciated for A/P status, the previous roll mode disengages andthe airplane turns to track the LOC.
Autopilot ApproachAt 2,500 Feet.Radio Altitude and Rising Runwayare displayed Use of Heading Select ensures LOC is intercepted. Localiser capture is variable. Depending on the course deviation. Not later than ½ dot on the deviation scale
Autopilot ApproachSINGLE CH will be annunciated at LOC capture At LOC Capture. Arm APP mode
Autopilot ApproachGo Around Mode of TOGA is armed at 2,000 Ft RAwith both FD switches ON.Or above 2,000 Ft with flaps not up.Or above 2,000 Ft with Glide slope capture.TOGA switch on Thrust levers is now active. At LOC Capture. Arm APP mode ARM the second Autopilot Must be armed before 800 Ft RA
Glideslope CaptureGlideslope capture is inhibited prior to localizer capture.The G/S can be captured from above or below. Capture occurs at2/5 dot and results in the following:• G/S annunciates captured• previous pitch mode disengages• APP light extinguishes if localizer has also been captured• airplane pitch tracks the G/S• GA displayed on thrust mode display (N1 thrust limit).After VOR/LOC and G/S are both captured, the APP mode can beexited by:• pushing a TO/GA switch (Single autopilot)• disengaging A/P and turning off both F/D switches• retuning a VHF NAV receiver.
Autopilot ApproachGlide slope will capture at 2/5of a dot from above or below.At Glide slope CaptureSet Missed approach altitude.
Autopilot ApproachAt Glide slope capture ThrustMode annunciation changes toGA
Autopilot ApproachAt Glide slope capture ThrustMode annunciation changes toGA DC cross bus tie relay opensAfter Glide slope capture set missed approach altitude on the MCP.
After LOC and G/S CaptureShortly after capturing LOC or G/S and below 1500 feet RA:• the second A/P couples with the flight controls• test of the ILS deviation monitor system is performed and the G/Sand LOC display turns amber and flashes for 3 seconds.• FLARE armed is annunciated• the SINGLE CH annunciation extinguishes• A/P go–around mode arms but is not annunciated.Note: During a dual autopilot approach and after FLARE ARMannunciation, any attempted manual override of the autopilots willresult in an autopilot disconnect.The A/Ps disengage and the F/D command bars retract to indicatean invalid ILS signal.
Autopilot Approach AT 1500 Feet.Localiser and Glide slope Deviation Test
Autopilot Approach AT 1500 Feet. Second autopilot couples to controls. SINGLE CH extinguished. Second FCC Master light illuminates.Localiser and Glide slope Deviation Test
Autopilot ApproachAT 1500 Feet + 20 Seconds FLARE ARMS Annunciated by 1300 Feet RA
800 Feet Radio AltitudeThe second A/P must be engaged in CMD by 800 feet RA to execute adual channel A/P approach. Otherwise, CMD engagement of the secondA/P is inhibited.
Autopilot ApproachAT 800 FeetSecond Autopilot must beengaged before 800 Ft RA.
400 Feet Radio AltitudeThe stabilizer is automatically trimmed an additional amount nose up. Ifthe A/Ps subsequently disengage, forward control column force may berequired to hold the desired pitch attitude.If FLARE is not armed by approximately 350 feet RA, both A/Psautomatically disengage.
Autopilot ApproachAT 400 FeetAutopilot trims nose up.
Autopilot ApproachAT 350 FeetIf FLARE is not armedBoth autopilots disengage.
Autopilot ApproachAT 200 FeetRising runway begins to rise.
Autopilot ApproachAT MINIMUMSRadio or BARO Minimumsindicator and RA changecolour to amber and flash for3 seconds.Remain amber until touchdown or reset (RST) onEFIS control panel.
FlareThe A/P flare manoeuvre starts at approximately 50 feet RA and iscompleted at touchdown:• FLARE engaged is annunciated and F/D command bars retract.• the A/T begins retarding thrust at approximately 27 feet RA so as toreach idle at touchdown. A/T FMA annunciates RETARD.• the A/T automatically disengages approximately 2 seconds aftertouchdown.• the A/P must be manually disengaged after touchdown. Landing rolloutis executed manually after disengaging the A/P.
Autopilot ApproachAT 50 Feet RAAt approximately 50 Ft RA.The flare manoeuvre begins.Actual height depends ondescent rate.
Autopilot ApproachAT 50 Feet RAAt approximately 50 Ft RA.The flare manoeuvre begins. Flight Director BarsActual height depends on are removeddescent rate.
Autopilot ApproachAT 27 Feet RAAt approximately 27 Ft RA.The Auto Throttle beginsRetarding the Thrust.
Autopilot Approach2 Seconds after touchdownAuto throttle disconnects
Autopilot Approach2 Seconds after touchdownAuto throttle disconnectsAuto Pilots must be manuallydisconnected.
AFS FailuresPower interruption or loss may cause disengagement of the AFDSand/or A/T.Re–engagement is possible after power is restored.Dual channel A/P operation is possible only when two generatorsare powering the busses. Both IDG’s or 1 IDG and the APUGenerator.Two independent radio altimeters provide radio altitude to therespective FCCs.With a radio altimeter inoperative, the respective autopilot willdisconnect two seconds after LOC and GS capture.
LIMITATIONSAutopilot/Flight Director SystemVariations depend on tail number and local rules.Use of aileron trim with the autopilot engaged is prohibited.The aileron feel and centring unit is repositioned while the autopilotholds the control wheel neutral.Aileron trim will become effective when the autopilot is disconnected..Do not engage the autopilot for takeoff below 400 feet AGL.Airplanes operating under FAA Rules:For single channel operation during approach, the autopilot shall notremain engaged below 50 feet AGL
Do not use the autopilot below 100 feet radio altitude at airportpressure altitudes above 8,400 feet. (Tail number)Autoland capability may only be used to runways at or below 8,400feet pressure altitude (Tail number)Airplanes operating under FAA Rules: Maximum allowable windspeeds when landing weather minima are predicated on autolandoperations:• Headwind 25 knots• Crosswind 20 knots• Tailwind 10 knots.Maximum and minimum glideslope angles for autoland are 3.25degrees and 2.5 degrees respectively.Autoland capability may only be used with flaps 30 or 40 and bothengines operative..
What pitch mode is annunciated on the FMA after takeoffwhen the autopilot is first engaged in command?
What pitch mode is annunciated on the FMA after takeoffwhen the autopilot is first engaged in command?Pitch engages from TOGA into LVL CHG and the FMA isMCP SPD unless another pitch mode has been selected.
What is the minimum altitude (RA) for selecting CMD on thesecond autopilot during an ILS dual channel approach?
What is the minimum altitude (RA) for selecting CMD on thesecond autopilot during an ILS dual channel approach?Both VHF NAV receivers must be tuned to the ILSfrequency and the second autopilot must be engaged inCMD prior to 800 feet RA.
Auto Land Capability can only be used with;..............ENGINESAnd FLAPS........ OR........
Auto Land Capability can only be used with;BOTH..............ENGINES 30 40And FLAPS........ OR........ Limitations
During takeoff the flight director commands 15 degreesnose up when?
During takeoff the flight director commands 15 degreesnose up when?From 60 Knots until a good rate of climb is achieved andthen MCP (V2) +20.
Both F/D switches are ON for takeoff. The autopilot isengaged in CMD at 400 ft. Which pitch mode isannunciated on the FMA?
Both F/D switches are ON for takeoff. The autopilot isengaged in CMD at 400 ft. Which pitch mode isannunciated on the FMA?Pitch engages from TOGA into LVL CHG and the FMA isMCP SPD unless another pitch mode has been selected.
Antenna switching from tail to nose antenna occurs when?
Antenna switching from tail to nose antenna occurs when?When a LOC frequency is selected the VHF NAV radiosswitch from using the tail mounted VOR/LOC antenna tothe nose mounted LOC antenna when VOR/LOC mode isselected on the MCP. If VOR/LOC is annunciated on theFMA switching has occurred. If switching fails LOC mode isinhibited and will not annunciate.
What effect will an inoperative Radio Altimeter have on the Autopilot?
What effect will an inoperative Radio Altimeter have on the Autopilot?
What effect will an inoperative Radio Altimeter have on the Autopilot?The Left RA is used by FCC AThe Right RA is used by FCC B
What will happen if aileron trim is used while an auto pilot is engagedin Command?
What will happen if aileron trim is used while an auto pilot is engagedin Command? LIMITATIONS.
What will happen if aileron trim is used while an auto pilot is engagedin Command? LIMITATIONS. Use of aileron trim with the autopilot engaged is prohibited. The aileron feel and centring unit is repositioned while the autopilot holds the control wheel neutral. Aileron trim will become effective when the autopilot is disconnected.
The END of AUTO FLIGHT PART 2Now Take the test at www.theorycentre.com Or contact us at email@example.com