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OldFlyboy

Auto-Pilot is Still Confusing Me

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Finally!...I can climb to proper altitude, establish heading, and descend thanks to several of the good posts here on the forum.What I can NOT do is disengage the LNAV so that the APProach can be engaged. NAV seems to be disengaged at the AP head, both VORs are tuned properly, but I still cannot get APP to engage and the LNAV is still on the EHSI.Surely there is some switch or button That I am missing. This is a very interesting aircraft but it surely has lots of features that are totally unknown to me.Help will be gratefully accepted.Neal Howard

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Hi Neal, you do not disengage LNAV and then engage APP. With LNAV engaged, you arm APP so that it will take over from LNAV when all requirements are met, then sit back, relax and wait for it to happen (while manageing speed, descent planning, configuration etc.) Read the tutorial from page 86 for the overview, the transition itself is discussed on page 91.

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As many times as I have read the manual it still hid from me :(. I will read it again, CAREFULLY.I was not on a STAR but was being vectored by control...does that matter? NM I will read first and then ask as needed.Thanks Paul

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I'm not using APP often (almost never) but it should work the same way both when vectored or on STAR, but when vectored I first set FD to NAV, and when it captures the radial I set it to APP.Cheers.rolleyes.gif

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Neal,If you are looking at this autopilot as if it is a Boeing/MD/Airbus autopilot, you are setting yourself up for failure. Keep in mind that just as aircraft are made by different manufacturers, so are autopilots. The way each works is entirely dependant on who programmed it.Here are the main things to understand:On the pedestal:AP - turns the autopilot onYD - turns the yaw damper on (should be on from takeoff to short final in this type, if I recall correctly)On the glareshield:Lateral ModesHDG - holds a defined heading based on the heading knobNAV - follows a NAV course*APP - follows a LOC or LOC+GS (ILS)*NAV course is a set course defined by the selected source. If you have LNAV selected, the AP's NAV function follows the FMS computed course. If in V/L (VOR/LOC) mode, it follows a radial or inbound/outbound course, set by tuning a VOR or LOCalizer on the radio, and setting the inbound course with the CRS knob. In a sense, there is no dedicated LNAV mode in this aircraft, per se.Vertical ModesALT - holds the altitude of when the button was pressed (best selected when you have established level flight)ALT SEL - climbs/descends to the ALTitude that has been preSELected, using V/S or IASV/S** - climbs/descends at the preselected vertical speed (select V/S and adjust with the wheel on the pedestal)IAS** - climbs/descends at the preselected Indicated AirSpeed (select IAS and adjust on the pedestal as above)**V/S and IAS can be used alone, or with an "end goal" set by ALT SEL. When you use them in combination, V/S or IAS will show ON and ALT SEL with show an amber "CAP" (or similar - I know it's amber).Now to address your issues:While in the LNAV mode of the NAV function, you can still set up your VOR/LOC courses by clicking the V/L button once. When you do this, a magenta course needle appears. Set it using the course knob. This frees up time for later, while your A/P can still do nav work for you. Chances are, ATC will vector you off of your filed/flown route or arrival, which will require the use of HDG anyway, but planning ahead never hurt anyone.In order to APP to engage, the aircraft needs to be off of LNAV and on V/L. Once you are ready to switch off of LNAV and onto V/L, click V/L twice (remember, clicking once just allows you to align the course in the background, as we did earlier). On the second click, the aircraft will switch to V/L mode, allowing you to engage APP.Being vectored by ATC does not matter. Most likely, all that means is that you're on a set heading, and will be vectored to intercept the approach course. In this case, an intercept of no more than 30 degrees from the final course will be given, and when instructed to make the turn, dial that in using the HDG knob. At this point, engage APP mode by clicking on it. At first, it will show "CAP" in amber to show it is primed to take over as soon as it gets within tolerances of the localizer beam. Once it kicks in (and if ATC vectored properly) once you hit the glideslope, it should guide you down. For the purposes of realism, kick off the A/P at 1000' (or company policy) and kill the YD at 200' (to make sure you land the plane instead of leaving a crater, you can ignore the YD until taxi off, because the non-flying pilot would do this for you).Hope this helps. If you have further questions, PM or ask here.Kyle

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