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Cessna Citation X

6,584 bytes added, 23:14, 15 November 2013
Autopilot instructions
* max 20 kts
<!-- During descent use the auto-pilot (VS mode) to control the rate of descent, and the throttle to control airspeed. -->In order to effect the initial speed reduction, the place the throttle in idle. As you deploy the larger flaps levels (15+) the aircraft can slow down quite quickly, and you will have to actively manage the carefully use throttle and elevators to avoid a dramatic loss of airspeedand stall. Particularly for the full flaps extension it is very difficult to maintain sufficient airspeed to prevent fast descent so deploy these only when you are quite near really close to the runway.
=== The autopilot ===
[[File:Citation-x-autopilot.png|thumb|Cockpit screenshot with highlighting of autopilot features (designer of Citation X plane: Syd Adams]]
''As of version 2.12, the autopilot appears to still have some stability issues, and using either the horizontal localiser or glideslope locking of an ILS signal caused the autopilot to put me into a highly unstable situation (extreme bank angle, upside down), although on the forum I have read of others who have not experienced these difficulties and apparently have carried out semi-automatic landings with the Citation X autopilot. If you encounter instability in any other autopilot mode you can try to turn off auto-coordination (i.e. do not use option --enable-auto-coordination option, which links rudder to aileron movements). Also you must only engage the autopilot from a stable situation, i.e. level or small bank and pitch angles. Please note that I have no knowledge of the internals of the autopilot, so some of the information below might be inaccurate''
Before the flight you should set the route in the [[route manager]]. In the explanation it is assumed you are familiar with basic autopilot operation in the Cessna, although the Citation X autopilot differs in many aspects. This description is not an exhaustive description of the autopilot modes, but rather a summary that should be sufficient to get you started.
The autopilot can be controlled either from the unit at the top of the instrument panel (marked in red), or from the dedicated GUI menu (F11) (marked in green). The keys in the cockpit will light up according to which autopilot mode you are in - no direct visual feedback is associated with key presses in the GUI window but the actual mode is shown in the top of the window. The current horizontal and vertical mode are shown in the top part of the GUI window as well as in the top of the primary flight display (PFD, the left glas panel on pilot side).
Basic mode
* AP: engages/disengages the autopilot - this switch works as a toggle switch. On first engaging the autopilot, it will reduce the bank angle to zero and keep the pitch direction. You can adjust the pitch with the 'nose' up/dn wheel on the autopilot unit, or equivalently the UP and DN buttons on the GUI. It is no longer possible to control the attitude or climb and sink rate directly with the elevator as the autopilot will adjust the elevator trim to counter any movement of the yoke.
(Note that this behaviour is slightly different to that described in <ref>[]</ref>)
* STBY: cancel all horizontal and vertical modes and revert to basic mode of pitch and roll control
Horizontal modes
* HDG: turn into the direction set by the heading bug and follow it. Although there is a cockput knob for adjusting this in the central console on both the pilot and co-pilot side, it is not practical to use unless you have multiple views enabled or use the autopilot GUI as you cannot at the same time operate the knob and look and its effect. So the best way is to use the GUI to set this. The current position of the heading bug is shown on the horizontal indicator in the centre bottom part of the PFD and as a number in the bottom left of the PFD.
* NAV: Navigation mode. ''Choosing the NAV source:'' For this you use the two buttons NAV and FMS in the unit above the PFD (marked blue) (or equivalent buttons in the GUI). NAV will select the VOR tracking mode (pressing it will toggle between tracking NAV1 and NAV2 receivers), and FMS will follow the flight plan defined through the [[route manager]]. Note that changing from FMS to NAV1 or NAV2 mode and vice versa will disengage all horizontal and vertical modes and put autopilot into standby mode. In the NAV mode the autopilot will intercept and then track the selected radial of the VOR station similar to a Cessna. The radial can be selected in the GUI, with the knob in the central panel or with the knob in the auxiliary HSI. Both HDG and NAV mode can be engaged at the same time - in this case the HDG bug will select the intercept direction. The HDG mode will automatically disengage when the autopilot turns to line up with the radial. In the FMS mode, the plane will fly from waypoint to waypoint, starting with the currently active one (the horizontal mode indicator then shows LNAV).
''The NAV mode AP might not be stable when the NAV receiver is tuned to an ILS frequency''
Vertical modes
* VS: set the vertical speed in ft/min. If the mode is engaged the target sink or climb rate is indicated as a light blue number above the vertical speed indicator in the PFD
* ALT: when this button is pressed the current altitude will be held. The target altitude can be adjusted in the GUI (ASEL) or (theoretically) with the ASEL knob on the co-pilot side of the central panel. The altitude is specified in terms of flight level (hundreds of feet), and the target altitude is also shown as purple number above the altitude indicator in the PFD
* FLC (Flight Level Change): In this mode a target airspeed is set (indicated as number above the air speed indicator in PFD), which the autopilot will match by lowering the nose if the plane is too slow, and raising it, when it is too fast. This mode will automatically disengage when reaching the target altitude. Conversely, if you are already flying at the pre-selected altitude (or have recently pressed ALT), then this mode does not even engage.
* VNAV This button can only be pressed if a route has been defined and the FMS mode has been selected. It will then follow the preset altitudes defined the [[route manager]] (again as flight level, i.e. in hundreds of feet). ''Watch out: if no altitude has been defined for a waypoint then a default altitude of 0 ft seems to be assumed. This might get you into serious trouble, of course.''
Combined modes
* APP: Approach mode is supposed to first intercept and track localiser of ILS beacon, and then intercept and follow the glideslope. On my trials this resulted in unstable AP behaviour.
* BC: Back-course follows an ILS radial in the opposite direction (e.g. for landing from the opposite side). After I could not get APP to work properly I did not bother testing this mode.
Modifier switches
* BANK: (relevant for horizontal modes) Limit bank angle to 17° making for wider turns - generally good idea to have this depressed while cruising
The CO and YD buttons are active buttons in the cockpit but do not seem to have any effect.
=== Configuration speed limits <ref>(Citation X - Section III Instrument and Avionics)[]</ref> ===

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