2 Quick Questions About NAV/GPS Switch

k_camacho11 wrote:

I usually land my plane by having the NAV/GPS switch set to GPS and setting the approach on my GPS, then the autopilot lines up with the runway pretty good. But I just wanted to know, that if u have the NAV/GPS switch set to NAV, along with the Runway ILS frequency set in the NAV1 Radio, will the airplane lineup with the runway better or will it be the same? Also...what does the ILS button in the A321 do? Thanks.

First off, see if this helps you:

https://forum.flyawaysimulation.com/forum/topic/8080/ils-approach-guide-tutorial/

The GPS is a lateral feature meaning that setting up a predefined route and following it will only follow left / right - so no altitude coverage is involved. This means that if you select Vectors To Final on your GPS and hit NAV when the GPS/NAV switch is on GPS, then you will follow the vectors to final aiming straight down the centerline - however you will not descend. This is a fairly unconventional method and can only be described as some sort of a GPS Approach.

However, if you are:
- Switching GPS/NAV to NAV
- Inputting the ILS frequency into NAV1
- Activating the radios
- Inputting runway heading into the CRS heading

...and becoming established on the localiser, then you will see on your HSI a center fixed arrow and two lines that tend to wobble about either side - similar to the below:

This allows you to fly by hand or by autopilot. By hand you will be following the needles both vertically and laterally down to DH (lowest possible height AGL before you must go around with no visual reference to the runway) or engaging the ILS button (approach hold) will fly the approach for you.

Principally, in answer to your question, it won't "line up better" - it'll enable you to descend in the correct profile and line up on the centerline. You former method will only line you up on the centerline. You can always do this and descend of your own accord using the PAPIs as guidance.

I hope that helps 👍

Thanks a bunch man!

Thanks a lot, it really helped. So when I switch to NAV from the GPS/NAV switch and have my runway heading set in the COURSE from about 10 miles out...then I hit APP button and the aircract will lineup with the runway and decend by itself until it has reached 500 ft?

k_camacho11 wrote:

Thanks a lot, it really helped. So when I switch to NAV from the GPS/NAV switch and have my runway heading set in the COURSE from about 10 miles out...then I hit APP button and the aircract will lineup with the runway and decend by itself until it has reached 500 ft?

Yes, providing that you have the correct frequency in NAV1 and you aren't going too fast (around 170 KIAS is good).

Good luck!

K thanks. When I input the runway heading in COURSE, I just put the heading right? I don't press the COURSE button on the AutoPilot? I just put in the heading and then hit the NAV button?

The APS will decend the aircraft all the way to the ground if you let it, it wont stop at 500ft. Its certainly not reccomended since it will usually send it slamming into the runway pretty hard. At 500ft, switch it off and land yourself.

On a side note, I like to watch AI traffic land. Its usually pretty rough! I literally watch an AI Cessna land itself in a field next to the runway. It missed completely, then went crashing into trees and took off again.

😳 😳 😳

k_camacho11 wrote:

K thanks. When I input the runway heading in COURSE, I just put the heading right? I don't press the COURSE button on the AutoPilot? I just put in the heading and then hit the NAV button?

Not quite. IOf yo look on the approach charts, the runway heading is not always the same as the Course heading for the approach (but it is close). Like KSFO Runway 28R the course would actually be 283.

HERE IS A TUTORIAL LINK TO LEARN HOW TO READ APPROACH PLATES. Hope it helps

http://www.fsstation.com/tutorials/interpreting-approach-plates.html

jellrod wrote:

k_camacho11 wrote:

K thanks. When I input the runway heading in COURSE, I just put the heading right? I don't press the COURSE button on the AutoPilot? I just put in the heading and then hit the NAV button?

Not quite. IOf yo look on the approach charts, the runway heading is not always the same as the Course heading for the approach (but it is close). Like KSFO Runway 28R the course would actually be 283.

HERE IS A TUTORIAL LINK TO LEARN HOW TO READ APPROACH PLATES. Hope it helps

http://www.fsstation.com/tutorials/interpreting-approach-plates.html

I'm sorry, it's too complicated for me. I just wanted to know if u press the COURSE button or not? "Not quite" doesn't really give me an answer.

I dont know if they way I have been doing it is right, but all I know is that it always gets me lined up perfectly, captures the localizer, and gets me on the glide slope...

In the 737, I put the runway heading into the Course field. I tune into the ILS Freq when Im about 30miles away, and get ready as I reach the intersection. Once Ive intersected and captured the localizer, I make sure that NAV is selected, the Course is on runway heading, and make sure Im at the proper altitude and its set. I then activate the Approach switch is turned on.

Which the Approach switch, it will line you up, and once in the glide slope, will begin to decend. When I learned to do this, I would test it in clear weather, then to perfect it, would do it again in 1/8mi visibility. This ensures that you are blind the whole way down, and cant see anything until just off the end of the runway. I will keep the GPS open as well as a visual reffernce to the DME, plus you can see the glide slope on GPS as well.

jellrod wrote:

k_camacho11 wrote:

K thanks. When I input the runway heading in COURSE, I just put the heading right? I don't press the COURSE button on the AutoPilot? I just put in the heading and then hit the NAV button?

Not quite. IOf yo look on the approach charts, the runway heading is not always the same as the Course heading for the approach (but it is close). Like KSFO Runway 28R the course would actually be 283.

HERE IS A TUTORIAL LINK TO LEARN HOW TO READ APPROACH PLATES. Hope it helps

http://www.fsstation.com/tutorials/interpreting-approach-plates.html

The runway heading in that case is 283 - it's only runway numbers that are to the nearest 10. 280 is not the runway heading - it's the runway heading to the nearest 10. Runway course isn't a phrase commonly used.

OK - easy way. Put in the correct freq for the ILS runway youre assigned. Make sure you have the FD (Flight Director) ON. Put the runway number (close enough) into the COURSE and press the APP Switch ON and of you are close enough to the localizer you should land straight and decend on course. Remember, turn of the Autothrottle and AP about 300 feet from landing or it will be a hard one. You need to fly the bird in the last few few.