自动飞行的操作

Bullet level 24 pt.Arial bold sentence case,Second level 20 pt.Arial bold sentence case,Third level 18 pt.Arial bold sentence case,Forth level 16 pt.Arial bold sentence case,*,NBAA 2003,#1,Title 28 Pt.Arial Bold Title Case,Civil Aviation Flight University of China,Auto flight Operations,自动飞行的操作,Auto flight Operations,Civil Aviation Flight University of China,The A/T and autopilot can be operated throughout most of the flight,and on certain aircraft down to touchdown using,autoland,systems.During take-off and initial climb the A/T is used extensively to hold required engine thrust until climb speeds are achieved.Whilst climbing to cruise altitude the autopilot is normally operated in the SPEED HOLD mode for a constant IAS/Mach whilst the A/T maintains engine power at scheduled settings.,At the top-of-climb,the autopilot automatically captures cruise altitude whilst the A/T regulates engine thrust to achieve desired cruise Mach.At the same time,and subsequently during the remainder of the flight,the autopilot can be coupled to hold a set heading or a VOR track,but is normally programmed to maintain the track of a selected flight plan using the FMC.In this mode,the autopilot initiates any track changes that are needed at turning points on command from the FMC.,Auto flight Operations,Civil Aviation Flight University of China,The performance computing capabilities of the FMC allow the autopilot and A/T to initiate descent and maintain an optimum descent profile.The systems are capable of operating in the SPEED HOLD or VERTICAL SPEED HOLD modes.When in the terminal area of a major airport,the systems can be coupled to an ILS localizer track and,glidepath,whilst at the same time achieving a stable speed prior to landing.,In the,autoland,mode such systems can automatically initiate a flare in response to radar altimeter information,and at the same time reduce engine thrust during the flare,finally controlling the rollout,and using,autobrake,to bring the aircraft to a virtual standstill right in the,centre,of the runway,Although considered as a separate system for many years,the AFDS is now commonly grouped with the processors that control the EFIS system and FMC functions in a fully integrated,autoflight,and automatic navigation system.,Auto flight Operations,Civil Aviation Flight University of China,Autoflight,Protection,A modern,autoflight,system is a powerful aircraft system which,if unchecked,could be capable of controlling the aircraft beyond approved speed and load limits.,As mentioned earlier,modern systems on large transport aircraft have all-important limitations programmed into the controlling processor.This prevents the aircraft from exceeding major limits such as V,MO,/M,MO,and also protects gear and flaps from,overspeed,.,At the lower end of the speed range,the autopilot makes appropriate pitch and power adjustments to ensure that the maximum angle of attack,the alpha,floor,is not exceeded.In each case,an appropriate message is,dis,played on the various mode,annunciators,typically accompanied by an aural caution alert.,Auto flight Operations,Civil Aviation Flight University of China,In the case of an,autoland,operation,some aspects of the AFCS are inhibited or reduced in sensitivity and response rate.Just as with the older autopilots,glideslope,sensitivity is reduced below about 300 ft radio altitude.,In aircraft with,autoland,capability,at about 200 ft RA,the longitudinal axis is aligned with the centerline of the ILS runway,with rudder and aileron input used to keep the aircraft tracking the centerline;at about 100 ft RA,the alpha floor protection is inhibited,otherwise the,autoland,system could not flare the aircraft for landing.The pitch trim may be wound well back out of trim,to give the elevator sufficient authority for the flare.,At this point,if the pilot decides to disconnect the autopilot and fly manually,a forward force of some forty pounds may be required to counter the trim.Similarly,the GA mode is inhibited at about 5 ft RA.,Auto flight Operations,Autoland,Civil Aviation Flight University of China,Autoland,Status,Autoland,status,annunciators,like the one shown at Figure 3.18,are provided so that pilots can monitor the progress of the,autoland,maneuver,along with other AFDS mode annunciations,A typical sequence of annunciations will advise the crew that the,autoland,systems are in the green,following a system self-test at 1,500 ft RA.The electrical system channels are isolated,and the,autoland,functions of runway alignment(drift correction),flare,landing and rollout are armed;these,submodes,are not shown as armed,but are only presented as the active mode at the appropriate time.,Auto flight Operations,Autoland,Figure 3.18,Autoland,Status,Annunciators,Civil Aviation Flight University of China,Autoland,Status,Annunciators,Upper indicator indicates LAND 3 when three autopilot systems and required airplane system inputs are operable in approach mode.It indicates LAND 2 when only two autopilot