NAV & Backcourse ?

[ReverseThrust]

What is the purpose of the NAV hold selector/switch (on the autopilot panel) and the Backcourse hold switch??

Do they have any part of ILS landings?

Thanks...

[Scottler]

Easiest definition of back course I could come up with:

The backcourse is used when, for example, you're attempting a go around and the runway is behind you.

To keep the numbers simple, a runway with the heading of 090 also has runway going the other way with a heading of 270...try to visualize here...lol

So if you've got yourself set up for landing on runway 9, and you miss it, keeping everything set for 9 won't help you much if you're flying away from it, know what I mean?

click back course and your A/P will know that the opposite of 9 is 27...

Sorry if this is too confusing, it took me a while to get it too.  Hopefully it'll hold you over til someone can explain it better.  lol

[Bruce]

I dont know if this is correct but once i was flying to a run way ils approch i dont remember which air port it was. with the frequency pluged in to nav1 radio. for some reason atc vector me to the other end of the run way i guess due to weather change. so i said let me try and hit the back course button and to my suprise i had the localizer right on target all the way down to the run way but not the glide slope so in my mind i taught it was the the purpose of the back course. i might be wrong or just got lucky that day.

[Heber98]

NAV hold is used to track VOR radials or if you switch the NAV/GPS to GPS it will hold the GPS course for a filed flightplan.

Backcourse is used in two ways:
If you are landing on a runway that doesn't have ILS, however the other end of the runway does have it, you can dial in the ILS freq and course for the opposite end and use backcourse and the autopilot will track the centerline to your end of the runway like a localizer (no glideslope). If you tune the course of the runway you are actually landing on, the needle will be deflected to the wrong side. Still works but can be confusing.

Backcourse can be used in instrument approaches, Aspen is an example with a backcourse from a nearby localizer being used in the missed approach procedure.

[hiflyphil]

Try taking the instrument training lessons with Rod, he'll tell you all about it, set you up for ILS approachs, get you into holding patterns all using the nav aids you inquired about.
But don't bother taking the exam at the end its a total mystery what she wants you to do.


Phil  ;D

[Scottler]

But don't bother taking the exam at the end its a total mystery what she wants you to do.

From what I've heard/read/experienced, that's pretty standard advice for all of the checkrides.  lol

[ReverseThrust]

Thanks Guys.. that helps!

[fisharno]

Bruce;

FS's ATC will only vector you to the default runway of all airports.

Example;

If you're aproaching your destination with the intention of landing on RW 9. You contact ATC and they'll vector you something like, "Make right base, RW 27 to land".
Runway 27 would be the default RW for that airport.
The way to change it would be to set your weather so the wind comes out of 270.

Remember, you'll always takeoff and land into the wind.