kutyafal

Mitsubishi MU-2: APR vs VORAPR buttons ?!?

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First, I love the plane! Good job so far! The question I have, what is the difference between the APR and VORAPR modes?  So far what I can determine APR captures glideslope and directs to a nice landing while VORAPR mode directs me straight into the ground... :P

Any help is appreciated!

Oh, one more thing, the DMA indicator just above the transponder seems to be missing a period before the last decimal digit. At least compared to the distance value on the HSI it seems to show the same numbers given the same NAV source but the missing decimal point confused me at first.             

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Hi Folks,

Right into the ground - LOL - what's not to like ?

Too funny...

I have the plane but haven't invested the time to learn it yet...

I'll gladly read the responses though...

:biggrin:

Regards,
Scott

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VOR/APR is only a lateral mode, so it controls left/right, but not your glide path. For that you can refer to charts which show the altitude vs. DME from the runway.

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Hmm, but doesn't NAV mode do the same thing? Since it tracks a VOR for lateral guidance it would be the same as VORAPR ?  What more does VORAPR add to the picture?

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There was a discussion on the subject albeit for ver 1.6. in this link/

bob

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1 hour ago, kutyafal said:

Hmm, but doesn't NAV mode do the same thing? Since it tracks a VOR for lateral guidance it would be the same as VORAPR ?  What more does VORAPR add to the picture?

I am not familiar with the specific aircraft's systems, but...

I'm pretty sure VORAPR is similar to LOC on other autopilots, whereas APR is like APP on other autopilots. So you'd use VORAPR to line up for an approach to a runway without vertical guidance, i.e. localiser only, no glideslope. Then fly the descent manually. Someone can correct me on that if they know the systems exactly, but as far as NAV versus LOC is concerned...

With that in mind, it might seem that there'd be no difference between using NAV or LOC (or in your case VORAPR) to track the localiser in order to line up on a runway, but there is, because there is a difference in how the autopilot works for NAV, and how it works for LOC...

LOC will track the localiser radio signal beam as accurately as is possible, with much more accurate steering cues being given to the autopilot, (this is because it is trying to get you down onto a bit of tarmac which is 100 yards wide), so it will try to keep you pointed right toward the thing as best it can. Conversely,  NAV mode typically tracks a known position of the nav aid and calculates a track to it, so it isn't concerned with trying to keep you spectacularly nailed onto a precise heading, so long as it gets you to pass over the nav aid, and realistically, if your were within say 500 feet laterally of a VOR when using it to navigate across country up at 10,000 feet, it would not really be a big deal to not pass directly overhead of the thing, whereas you'd want to be coming right at it for lining up a landing. The variation in how the autopilot does these different things on aircraft with FMCs and all kinds of other fancy navigational gizmos, are implemented by either enabling or inhibiting additional signal sources, such as GPS positional data, nav aid triangulation cross references etc.

Which one you might choose to use would probably depend on whether you were doing a precision approach, or maybe something like a DME arc approach to a localiser only landing aid.

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