G1000 KAP 140 NAV to APR transition question

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Chris B
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Re: G1000 KAP 140 NAV to APR transition question

Post by Chris B » Sat Oct 18, 2014 1:11 am

RC7 wrote:you really have to watch it like a hawk if you are flying a coupled approach. I taught my students to keep their hand on the disconnect button during approach as a reminder that YOU are the one flying the airplane...
To be fair, you also have to watch the GFC700 carefully. The difference is that - without exception - the guy in the left seat causes the problems.

The GFC700 does exactly what you told it to do, which is sometimes not what you wanted it to do... :oops:

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Re: G1000 KAP 140 NAV to APR transition question

Post by Eric N » Thu Dec 11, 2014 8:24 pm

I posted back in Oct. about the KAP 140 turning at less-than-standard rate in APR mode, but couldn't cite a source. I now recall that I recently saw this referred to in Max Prescott's G1000 Handbook, in the chapter on instrument flying. "The NAV mode generally makes turns at standard rate, while the APR mode makes turns at less than standard rate....it may overshoot the 90deg. turns found in the standard "T" configuration used for many GPS approaches. That's why you'll want to stay in NAV mode until after you make the turn..." This is also how we were taught in the new owner's course at the Diamond Flight Center when we picked up our aircraft, and what my experience has been in the air. So there it is, FWIW.
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Re: G1000 KAP 140 NAV to APR transition question

Post by LTek1 » Tue Dec 23, 2014 3:20 pm

Eric N wrote:I posted back in Oct. about the KAP 140 turning at less-than-standard rate in APR mode, but couldn't cite a source. I now recall that I recently saw this referred to in Max Prescott's G1000 Handbook, in the chapter on instrument flying. "The NAV mode generally makes turns at standard rate, while the APR mode makes turns at less than standard rate....it may overshoot the 90deg. turns found in the standard "T" configuration used for many GPS approaches. That's why you'll want to stay in NAV mode until after you make the turn..." This is also how we were taught in the new owner's course at the Diamond Flight Center when we picked up our aircraft, and what my experience has been in the air. So there it is, FWIW.
I'm a few months in to my IFR training, so forgive what might be a dumb question:

In a GPS approach with no vertical guidance, what is the function of switching to APR mode instead of just leaving it in NAV? Certainly I'd switch to APR for an ILS approach to capture the glideslope.. but I'm not sure I totally understand the purpose of APR even for a Localizer approach. What's the difference between just toggling my CDI source to VLOC1 and feeding that to the autopilot, as opposed to arming or toggling APR mode?

I've definitely noticed the tendency to overshoot 90 degree intercepts in APR ARM mode, so have just left it in NAV mode on GPS approaches. What am I missing by not toggling to APR after the turn?
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Avidyne Entegra (!), Dual GNS430, KAP140
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Re: G1000 KAP 140 NAV to APR transition question

Post by carym » Tue Dec 23, 2014 4:40 pm

I believe that if you leave it in NAV mode it will not automatically fly the missed approach if needed. Flying a missed approach is a busy time and you don't want to be turning dials and pressing buttons unnecessarily. If the full procedure is loaded, and you are in APR mode, then when it is time to go missed you just hit the SUSP button to get the autopilot to continue to fly the missed approach. If I am incorrect then I am sure others will straighten me out.

In all the instrument approaches I have flown in actual I have rarely had to go missed. But on one occasion it was at night, the field was down to about 400 feet, and I wasn't fully stabilized on the approach (ATC didn't let me descend in time). I knew the approach was no good and when I went missed the already high anxiety level skyrocketed. At such times you really want to have to perform the minimum amount of tasks needed.
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Re: G1000 KAP 140 NAV to APR transition question

Post by Rick » Tue Dec 23, 2014 5:59 pm

Lee, in APR mode, the AP tracks the course with greater precision than in NAV mode. APR mode does more than just activate vertical guidance - the AP will make more aggressive course corrections and maintain tighter tolerances.
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Re: G1000 KAP 140 NAV to APR transition question

Post by TJS » Tue Apr 16, 2019 2:27 am

I have been having trouble with the KAP140 as it behaves fine in NAV mode for cruise flight, but I haven’t been able to get it to fly a GPS approach properly. When flying the GPS approach I get to the IAF with the KAP140 in NAV mode; in the approach it tracks the first leg and I set APR mode. Once it turns to final the G1000 indicates that it has changed nav source(from terminal to LNAV) and the KAP140 flashes looking for new input, this where I get confused. I am not sure why the G1000 indicates a change in nav source and I suspect that is why the KAP140 quits. Is there something I am missing or a something on the G1000 that is not right?
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Re: G1000 KAP 140 NAV to APR transition question

Post by carym » Tue Apr 16, 2019 12:30 pm

This may sound silly, and i apologize if it is, but did you enter the approach into the g1000 with all the fixes? I have at times forgotten to put in the approach.
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Re: G1000 KAP 140 NAV to APR transition question

Post by chili4way » Tue Apr 16, 2019 1:35 pm

This http://flywithhoward.com/wp-content/upl ... proach.pdf may offer some ideas. (It's not G1000, it's GTN650). I noted that this suggests waiting until after the G1000 mode switches from NAV to LPV before activating APR on the KAP140. However, this assumes that the G1000 provides the required vertical guidance to the KAP140 without the extra "enable APR output" steps that appear to be required for the GTN650.
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Re: G1000 KAP 140 NAV to APR transition question

Post by Rich » Tue Apr 16, 2019 2:10 pm

Lee, is your G1000 WAAS? If not, LNAV is what I would expect to see for any GPS approach. It indicates a change of operating mode, not a change of input. These days my GNS units will usually display LPV, LP+V or LNAV+V, but they are both WAAS.

I don't know what the AP flashing means in this case - what is it displaying while flashing?
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Re: G1000 KAP 140 NAV to APR transition question

Post by Rich » Tue Apr 16, 2019 2:15 pm

carym wrote:
Tue Apr 16, 2019 12:30 pm
This may sound silly, and i apologize if it is, but did you enter the approach into the g1000 with all the fixes? I have at times forgotten to put in the approach.
Cary
I don't know that it applies to the G1000, but I would assume so: Is the approach Loaded or is it Activated? It needs to be the latter to fly it.
2002 DA40: MT, PF, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal.
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