PILOT’S GUIDE Retrofit Autopilot Systems
PILOT’S GUIDERetrofit Autopilot SystemsBuyer’s GuideB yP a u lN o v a c e kAutopilots come in many A Little HistoryIt all began with an inventiondifferent forms, but they developed by Elmer Sperry in the1900s — the gyroscope.all perform the same task, earlyThis device uses a spinningwhich is to relieve the mass that keeps its orientationwhile an airplane moves aroundpilot from the sometimes- it, which is the basic principlemundane task of flying the underlying today’s artificial horizon gyro.aircraft. They accomplishOriginally designed to helpships steer a steady course,this in a few different ways,Elmer’s son, Lawrence Sperry,but all use the three basic used his father’s invention tosuccessfully launch an aircraftbuilding blocks of an company specializing in aircraftautopilot: sensing position, control systems. Along the way,the Lawrence Sperry Aircraft Co.computing desired goal built the Messenger airplane andand driving flight controls gyro-based instruments that arestill in use today. Sperry beganto achieve the goal. experiments in the early 1920sCentury Flight Systems’ newest autopilotline, the Triden series.using gyros to sense attitude andusing motors to drive the controls, resulting in the precursor ofthe modern-day autopilot.During the 1930s and 1940s,the Sperry autopilot was furtherdeveloped for use in airliners andas an integral part of precisionbombsights. The famous Nordenbombsight of World War II usedprecision optics, a mechanicalcomputer and autopilot technology to stabilize the heavy bomberduring a bomb run. During therun, the bombardier controlledthe aircraft through use of theautopilot.- 58 -Continuing work by the SperryCorp. during and after thewar, as well as Minneapolis–Honeywell and other manufacturers, further refined the autopilot,making the components lighter,smaller and more capable. Overthe years, advances in electronics technology made it possiblefor autopilots to land an airplaneunder zero-visibility conditions.In 1964, Smiths Industries developed an autoland system forairliners, enabling landings inconditions far below previousminimums.Eventually, the autopilotevolved into the modern flightmanagement system using flyby-wire techniques to controlthe aircraft from takeoff throughlanding.Basic Autopilot FunctionsAn autopilot’s primary functionis to provide stability in one ormore axes. Let’s use the pitchaxis to illustrate this stabilityfunction. As an aircraft encounters turbulence, the attitudeindicator sends a signal to theautopilot computer indicatingthe nose has pitched up. Thecomputer processes this signaland sends a signal to the pitchservo instructing it to apply downelevator, thus bringing the aircraftback to level pitch. This stabilizContinued on page 60
AUTOPILOT nTruTrakModelDescriptionList Price20Roll axis with nav tracking, contained within turn-coordinator 6,400 – 8,86030Roll functions with altitude hold, trim prompting, containedwithin turn-coordinator 10,180 – 13,98030 AltStand-alone altitude hold, trim prompting 5,44040Roll axis, 3” panel mount 6,500 – 9,00050Roll functions with altitude hold, trim prompting, 3” panelmount 10,300 – 15,30055XFull-featured, radio stack mount 17,360 – 28,98060-1Roll channel, full-featured, 3” panel mount 7,90060-2Full-featured, 3” panel mount 14,00060 PSSStand-alone pitch, full-featured 8,20065Full-featured, pedestal mount 24,920 – 31,760Yaw DamperStand-alone or integral 5,200 – 6,360MAGIC 2100Integral part of MAGIC DFCSIncluded inEFIS packageKFC-225Full-featured for piston singles and twins, radio stack mount 38,000 – 60,000KFC-325Full-featured, EFIS compatible for turboprop, pedestalmount, RVSM compliantIncluded in EFIS at 310,000 (typical)IRoll axis with nav tracking, contained within turn-coordinator 6,75041Full-featured, pedestal mount 24,4952000Full-featured, radio stack mount 8,995 – 19,995TridenFull-featured, 3” panel mount 12,995 – 22,995AP-3CFull-featured, radio stack mount, single- and multi-enginepiston 14,650 – 16,150DigiTrakRoll channel, solid-state DG, GPS tracking 1,695 (2”), 1,745 (3”)Pictorial PilotDigiTrack within turn coordinator 2,095 (2”), 2,145 (3”)DigiFlight IIPanel mount (2”), GPS tracking with altitude hold 3,850DigiFlight II GPanel mount (2”), GPS steering with altitude hold 4,225DigiFlight II VSPanel mount (2”), GPS tracking with altitude hold, verticalspeed and trim prompting 4,350DigiFlight IIVSGPanel mount (2”), GPS steering with altitude hold, verticalspeed and trim prompting 4,725DigiFlight IIVSGVPanel mount (2”), GPS steering with altitude hold, verticalspeed, trim prompting and GPS VNAV 5,225DFC-200ATI/ASPanel (3”) or radio stack mount, full featured 6,900Sorcerer ASRadio stack mount, full-featured, GPS vertical mode, altitude 9,500preselect, airspeed selectAlTrak / VSStand-alone altitude hold, vertical speed select with VSmodel 1,695 – 1,995ADI Pilot IRoll autopilot with ADI, GPS tracking, digital DG 2,795ADI Pilot IIRoll & Pitch autopilot with ADI, Alt hold, GPS tracking,digital DG 3,995Note: The ranges of list prices reflect the different prices for installation kits and optional features.- 59 -
AUTOPILOT BUYER’S GUIDEContinued from page 58ing process repeats itself manytimes per second and keeps theaircraft balanced around a fixedattitude.Once basic stability has beenachieved around a set point — inthe steady state case, level attitude — the pilot can change theset point. This process is calledhomeostasis, in which stabilityis achieved around a preset, butresetable point. This homeostasis process works for all thebasic autopilot functions, such asheading and altitude hold.An autopilot works in much thesame way as does your body.Your body uses three interrelatedsystems to accomplish a task,even as simple a task as takinga drink of water. Your eyes seewhere the glass is on the table,then your brain processes theposition of the glass and determines what muscles are neededto lift the glass. An important partof this process is the open-loopfeedback that senses your movements and corrects for any necessary adjustments.While lifting the glass to takea drink, your eyes observe theimage of your arm raising theglass. This image is sent to yourbrain, where it is perceived thatyour arm is not going in the rightdirection. A corrective signal issent to your muscles instructingthem to move in the proper direction. The process, called feedback, then starts all over again,allowing the system to constantlysense and correct the actionsuntil the task is completed.As does your body, a gyroserves as the autopilot’s eyes,or sensors, sensing the currentposition of the aircraft in relationto the surface of the earth. Thecurrent position is sent to theautopilot computer, which performs all necessary calculations,then sends a signal to a motorthat moves the aircraft controlsurface. The aerodynamics ofthe aircraft respond to the controlmovement and provide feedbackto the gyro, which begins the process again.Depending on the model andcapabilities of the particular autopilot, either an artificial horizonor turn coordinator gyro is usedas the primary sensor. Additionalsensors also are used, suchas an air pressure sensor, todetermine altitude, and accelerometers to detect motion. Thecomputer performs all the computations necessary to controlthe aircraft. The computer outputis sent to a servo providing the“muscle” for each control axis.Meggitt/S-TECThe Meggitt/S-TEC family ofautopilots comprise the basic ofwing-levelers to fully integratedflight control systems. For simpleroll control, the System 20 is fullycontained in the turn coordinatorand roll servo. The upper end ofthe S-TEC line, the MAGIC 2100,is an integral part of its MeggittThe entire line of Meggitt/S-TEC autopilots, from simple wing-levelers to full-function flight controlsystems.- 60 -EFIS system as installed in thePiper Meridian and as retrofit intoturboprop aircraft.All S-TEC autopilot systemsuse hardware, servos and sensors common throughout theproduct line. This commonalitygives the aircraft owner significant advantages in serviceability,reliability and overall cost. It’salso the foundation of the S-TECupgrade/trade-in program, whichgives an autopilot buyer theoption of buying a system todayand upgrading it to a systemwith more features and functionslater. An owner can purchase aSystem 20 for just the roll axis,then later upgrade using thesame servo and mounts, thussaving hours of installation time.For the kit-built market, STEC has a program designedto specifically meet the specialneeds of custom installations.The company has specific kitsavailable for the more popularkit airplanes, such as Lancairs,Glasairs and others. If S-TECdoesn’t have an “approved” kitfor a specific kit airplane, thecompany will work with avionicsshops on a custom installationor possibly develop a kit for thatspecific airplane.S-TEC’s newest autopilotis borne from the marriage toMeggitt. The MAGIC 2100 digitalflight control system is an integralcomponent of the Meggitt MAGICline of control and display unitsand is not sold as a stand-alonesystem; however, plans are inthe works to provide stand-alonecapability in the future.The MAGIC 2100 DFCS isa digital attitude based flightcontrol system in an avionicsstack-mounted case containingthe mode selector/programmer,annunciator, roll, pitch and yawcomputers, including the servo
The Honeywell-Bendix/King KFC-225, a full-featured flight control system.amplifiers. The system also provides integrated altitude selectorand alerter modes.S-TEC is preparing to launchtwo new digital autopilots forOEM and retrofit applications.The first new product will be anembedded flight control system for the twin-turboprop andthe light jet market with all thefeatures of a full corporate jetautomatic flight control system,including autothrottle.The second initiative is thetop-to-bottom reinvention of thecompany’s autopilot line, with thegoal of providing additional features, such as WAAS approaches. Concept development of thenew autopilots is under way, andthe plan is to go from analog tofully digital architecture.For more information, contactMeggitt/S-TEC at 800-872-7832or visit www.S-TEC.com.Honeywell – Bendix/KingThe Bendix/King divisionof Honeywell has two lines ofautopilots, the Honeywell linefor the turboprop and corporatejet aircraft, and the Bendix/Kingline for general aviation aircraft.Honeywell absorbed the autopilotpioneers, Sperry, to become oneof the leading autopilot manufacturers since that first autopilotdesigned by Lawrence Sperry.Honeywell’s turboprop, jet andairline autopilots currently areintegrated into complete flightmanagement systems and arenot sold as retrofit autopilots, butits Bendix/King line of autopilotsare available for installations inmost of the general aviation fleet.The KAP-140 system isinstalled mainly as original equipment in the Cessna single-engineline of aircraft, but also is available for retrofit into select singleengine airplanes. The simple,yet fully featured KAP-140 usesthe turn coordinator as its primary sensor and includes threemodels: roll channel only, rolland pitch channels, and the fullyfunctional system that includesaltitude preselect.The bigger brother of the KAP140, the KFC-225 is an integrated, all-digital flight control systemthat combines the functions andfeatures of three separate avionics units: an autopilot computer,altitude pre-select/alerter, andoptional yaw damper. The KFC225’s simplicity of design andease-of-use gives pilots the ability to efficiently and effectivelymanage workload. For enhancedprecision and performance, thesystem’s advanced algorithmsutilize digital interfaces with GPSand EFIS.The KFC 325 is a three-axisdigital flight control system thatcan be installed with either theconventional electromechanicalflight instruments or electronicflight instrument systems (EFIS).For more information, contactHoneywell – Bendix/King at 877712-2386 or visit www3.bendixking.com.Century Flight SystemsCentury Flight Systems,based in Mineral Wells, Texas,began manufacturing autopilots- 61 -in the early 1950s. Don Mitchellfirst installed an autopilot in aBonanza under the trade nameAirBoy. Ever the innovator, thecompany grew and became EDOAire Mitchell in the mid-1960s,and has since installed autopilotsin just about every general aviation airplane.The company became CenturyFlight Systems in 1983, and itsprolific coverage of the entireautopilot spectrum is apparentwith its current offerings. As abasic roll-channel autopilot, thecompany still markets the CenturyI, which is wholly contained in aturn coordinator and roll servo.The line culminates in thenewly developed digital Tridenline of autopilots. All of its newerautopilots use the building blockmodular approach to installationsin which capabilities are added byjust adding components.The company currently offersthe Century I, 41, 2000 andTriden. The Century 41 is anolder, but reliable autopilot forupper-end piston twins and turboprops. The system comprises aremote-mount computer systemwith mode selector and annunciator available with gyros or interface units to allow the use of theexisting gyros.The Century 2000 is an affordable advanced position andrate-based flight control systemavailable in one, two or threeaxis configurations. The system is expandable, so featurescan be added to meet changing needs without replacing theentire autopilot. Standard featuresinclude advanced digital circuitry,GPS/VOR/LOC/BC intercept andtracking, glideslope capture andaltitude hold. Optional featuresinclude automatic/manual electrictrim, flight director, HSI or digitalContinued on following page
AUTOPILOT BUYER’S GUIDEContinued from page 61altitude preselect.Century Flight Systems’ newlydeveloped Triden series of flightcontrol systems uses advanceddigital circuitry to process position and rate data to producecomfortable flight dynamics inrough or smooth air.The Triden’s list of standardfeatures includes GPS/VOR/LOC/LOC REV coupling, glideslope coupling, selected angleintercept when using an HSI (45degree intercepts using a DG),altitude hold, voice prompter, attitude hold, vertical speed select,trim prompting and a crisp backlitLCD screen. The expandablearchitecture of the Triden seriesallows for easy upgrades, autotrim (manual electric trim), digitalaltitude pre-select, single-cueV-bar flight director and dualsensing yaw damper (based onaircraft approval).For more information, contact Century Flight Systemsat 940-325-2517 or visit www.CenturyFlight.com.CheltonChelton Aviation, based inDenton, Texas, is a subsidiary ofthe large Chelton Group of companies. Chelton Aviation develops the AP-3C, a digital autopilot.The design originated inBologna, Italy, as the AP-1 autopilot system in 1973, and wasdesigned by Professor GiuseppeBasile when he was teachingelectronics and control automation at the University of Bologna.In 1982, the AP-2B and AP-3Breceived FAA TSO certificationfor sale and use in U.S. aircraft.In July 2001, Chelton Avionicspurchased the product and overthe next year redesigned thecontroller unit to use the latest inThe full-featured AP-3Cautopilot from CheltonAviation.electronics technology.The autopilot is suitable forboth single- and multi-engineairplanes, and does not requireexternal adapters or altitude sensors. The pitch channel drivesthe pitch trim system and noelevator servo is required. Bothpitch and roll channels are AHRSstabilized, but the system also iscapable of interfacing with existing autopilot gyros and navigation signals. The computer/controller can be mounted in the6-inch avionics stack or pedestal.The AP-3C is a full-featuredautopilot with ILS tracking, GPSsteering (lateral and vertical),automatic pitch trim, altitudepreselect, vertical speed selectand pitch/roll angle hold. TheChelton autopilot is certified inmany of the more popular Beech,Cessna, Piper, Mooney, Lancairand Grumman American aircraft.The AP-3C system is compatiblewith any airplane platform giventhe proper and appropriate control mechanical interface.Three major componentsmake up the AP-3C system: thecontroller unit, roll servo andpitch trim servo. The autopilot isunique in the small aircraft industry because of its ability to flythe aircraft in the vertical chan-nel using only a pitch trim servowithout an elevator servo. Theconcept of flying the elevator surface using the pitch trim controlhas long been employed in largeaircraft and now is available to thesmall aircraft market.This method of flying the aircraft provides for a safer andmore turbulence-stable aircraft.This method also provides thecharacteristics of the aircraftalways being in proper pitch trimduring autopilot operation and disengagement.For more information, contactChelton Aviation at 940-320-3330or visit www.CheltonAviation.com.TruTrakTruTrak is a newcomer to theautopilot scene and currentlyis marketing only to the kit-builtand experimental crowd. Basedin Springdale, Ark., the companyprovides a multitude of autopilotand instrument choices for the kitbuilder at competitive prices.TruTrak even supplied the autopilot for the Virgin Atlantic GlobalFlyer — a much-relied-on systemfor pilot Steve Fossett on his solotrips around the world.TruTrak has delivered morethan 3,000 autopilot systemsand currently offers four productThe line of TruTrak autopilots designed and priced specially for the kit-built andexperimental aircraft market.- 62 -
lines, from the basic DigiTraksingle-axis system to the sophisticated and full-featured SorcererAS. The simple DigiTrak computer/controller is available inboth 2-inch and 3-inch instrument mountings. It only needsan external roll servo and a fewswitches to complete the installation.For less than 2,000, it provides a GPS-slaved solid-stateDG, GPS nav tracking, headingtracking, magnetic backup modeand control wheel steering.All TruTrak autopilots use abuilt-in magnetic sensor calibrated upon installation, thus providing heading information withoutthe need for a remote-mountedflux sensor. The DigiTrak also isavailable married to a turn coordinator called the Pictorial Pilot,available in 2-inch and 3-inchversions. Increased capability isgained by adding a pitch channelwith the DigiFlight II. The 2-inchcomputer/controller employs amore complete display, altitudehold and GPS steering. Somemodels of the DigiFlight II usea trim-sensing pitch servo toannunciate out-of-trim conditionsand control vertical speed.For even more capability,including ILS tracking, the DFC200 is a full-featured autopilotavailable in either 3-inch orradio-stack computer/controller.The newly released SorcererAS combines all the functions ofthe DFC-200 and includes GPSVNAV, digital altimeter, reverseLOC, selected-angle interceptand an altitude alerter.Servos, mounting brackets andlinkages for any of the TruTraksystems can be purchased andinstalled as required during theconstruction of a new aircraft.For the more popular kit-built orexperimental aircraft, TruTrakhas servo installation kits thatinclude aircraft specific mounting brackets and push rods at noadditional cost.To accommodate variationsin aircraft requirements, TruTrakprovides a choice of three different torque capability servos,which are mechanically interchangeable. The maximumtorque capability of the servo iselectronically set to the lowestvalue that allows the autopilotadequate control authority so thepilot can override the autopilotwith the least possible effort.The high-torque servo is a newdesign that allows the TruTrakautopilots to fly much largeraircraft than possible with thestandard servos. For example,the Lancair IV Turbine, L-39 andVirgin Atlantic Global Flyer allare flown using the high-torqueservo.Accessories to the autopilotsinclude a newly released attitudedirection indicator (ADI), whichuses solid-state gyro sensors(mechanical display) and manyinnovative warning annunciatorsthat indicate extreme bank andpitch angles. TruTrak also offersstand-alone 2-inch and 3-inchturn coordinat
Honeywell – Bendix/King The Bendix/King division of Honeywell has two lines of autopilots, the Honeywell line for the turboprop and corporate jet aircraft, and the Bendix/King line for general aviation aircraft. Honeywell absorbed the autopilot pioneers, Sperry, to become one of the leading autopilot manu-facturers since that first autopilot
3.0 Autopilot Overview 3.1 System 60-2 Programmer/Annunciator Fig. 3-1. System 60-2 Programmer/Annunciator The System 60-2 Programmer/Annunciator is a rate based autopilot that controls the roll and pitch axis of the aircraft. The autopilot's main func-tion is to convert pilot commands to logic signals for both the roll and pitch computers.
A pilot must be seated in the left pilot's seat, with seatbelt fastened, during all autopilot operations. Do not use autopilot during takeoff and landing. The GFC 500 AFCS preflight test must complete successfully prior to use of the autopilot, flight director or manual electric trim.
Honeywell KAP 140 Autopilot system (Sources: Honeywell KAP 140 Pilot’s guide – Honeywell KAP 140 Installation Manual) KAP 140 Two Axis with Altitude Preselect Operation - Introduction The KAP 140 Autopilot System included in the Beaver is a rate based digital autopilot
2 KAP 140 AUTOPILOT SYSTEM Rev. 1 Apr/02 General Description KAP 140 Single Axis Autopilot System The KAP 140 Single Axis system is an entry level digital panel-mount autopilot, offering lateral modes only with an electric trim option. KAP 140 Two Axis Autopilot System The KAP 140 Two Axis system pro-vides both lateral and vertical modes.
The Bendix/King KAP 140 2 Axis Autopilot provides the following modes of operation: 1. Roll (ROL) mode - keeps the wings level. 2. Vertical Speed (VS) mode - holds the climb or descent rate at the moment the autopilot is engaged or a manually-set climb or descent rate. Controlled using the up (UP) and down (DN) buttons. NOTE The autopilot can .
Track : Autopilot maintains a track between two waypoints created using a navigation system Vane : Autopilot maintains a course relative to an apparent wind angle Manual : Autopilot power steers rudder using joystick control When the ST6
The user interface The autopilot functions are presented slightly different on the different displays. This manual shows screen examples from both MFDs and AP44. Autopilot computer setup When the autopilot installation is completed, the setup of the autopilot computer must be performed. Failure in setting up the
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