Autopilot and VOR to VOR navigation

[Chris_F]

I've got a question about navigating VOR to VOR with the autopilot.  It's a FS2004 question and not a real world question, but I assume there's enough similarity for it to be valid here.

When navigating VOR to VOR on autopilot I find that as the VOR gets close the AP tries too hard to track the course.  I'd like to get the plane to overfly the first VOR and smoothly turn to the second.  I've been doing this in two ways:

1) When I'm getting close to the VOR I note my heading and dial this in to the AP and switch over from tracking the VOR course to heading hold.  I then watch as the VOR needle slews rapidly, indicating I flew over the VOR, and switch the nav radio to the next VOR and begin tracking that course.

2)  When I'm getting close to the VOR I simply switch over to the next VOR and course.

My question is this:  Is either of these the "correct" way?  Is there such a thing as a "correct" way?

My second question:

I really should look this up in the FS training material before asking here, but since I already have your attention...  When I plan an FS9 flight route following high altitude or low altitude airways I notice there are nav waypoints labeled as "intersections".  What is an "intersection" and how do I navigate by them?

[beaky]

Never done it in real life, but in FS9 I use the method you described. Passing the station, I'll set the heading bug to match whatever radial I want to track outbound, then set up for the next VOR.
But if your next VOR is out of range, you can go to "Heading" then change the OBS on the first VOR to a "from" indication on the desired radial, then go back to "nav". It's really the only smooth way to do it. Changing Nav 1 to the next VOR freq/radial also requires switching to heading hold for a moment, unless you happen to be staying on the same heading to the next station.
I'd imagine that in real life, if you try to make changes with the AP still slaved to the VOR, it'll work just as badly  as it does in the sim.
The best, of course, would be to have an AP that can select between Nav 1 and Nav 2, but I've never heard of such a thing.
 I will say from RL experience that even hand-flying to a VOR can be tricky when you get close- unless you've got everything just right and the wind doesn't change at all, you wind up s-turning a little. Best to not chase the needle and accept a slight deviation, as long as it's minimal.
It could be dangerous to miss the station on an IFR approach(terrain), but equally dangerous to be zig-zagging across the radial.

[Brett_Henderson]

Agreed.. The way you fly it would work just fine in the real world.. In fact, you'd probably impress a few people (even ATC).. because.. as a rule.. when you're flying real IMC you stop bothering to hold an exact radial when you get so close to the station that it takes more than 5 degree heading adjustments to "try" to keep the CDI centered... keep flying your current heading and just wait for the to/from flip.. Then, either start groping for the outbound radial..or.. the next VOR's inbound (sometimes it's outbound too (I'll get to intersections in a sec)). Some pilots start their turn early but if you do that on a checkride (not wait for the flip) you might be done with that checkride.

Intersections are imaginary, strategically placed (sometimes you wonder) fixes along airways or approaches. Normally either a reporting point (ATC will ask you to report when you reach one) or a change in heading or altitude (or both (some approaches are pretty complex)). For example: An initial approach fix (IAF) usually requires a turn and a descent. Final approach fixes (FAF) are almost always on runway heading and where you'd start your timer, for timed finals. They're referenced several ways. The most common would be on a  VOR radial at an exact distance (DME required) or where two VOR radials meet (intersect). You'd track one on NAV/VOR 1 while having the other tuned and dialed on NAV/VOR 2 (or switch frquencies and spin the OBS using just one NAV/VOR (not fun when you cant see your wingtips)) and when both CDIs center, you're at that intersection.

Some intersections (waypoints) can only be located by GPS or RNAV (happily all but obsolete) and you'd only be required to use/report them flying a GPS or RNAV approach. The great thing about modern GPSs is that they allow you to fly them all. You can fly a VOR, DME required approach because the intersections you'd need the DME to find are right there in the GPS to either fly to by screen or actually program in. If you've activated a GPS approach.. it will sequence you through each one.. unless you tell it otherwise (like if ATC just told you to hold at one).

Hope that makes sense...

[Chris_F]

Hope that makes sense...

It made plenty of sense, thanks.

[Poseidon]

One more comment here. The FS autopilot a a bit week in tracking a VOR in comparison to real aircrafts. In real life teh autopilot is more aggresive in maintaining the track. This is gathered information from aviation related forums. I am not a real life pilot.

[Brett_Henderson]

Yeah..  The A/P in the 177RG I fly will make up to a 30 degree correction.. briskly (including a near 30 degree bank) (the yoke can "bonk" your knuckle if you're not paying attention) to intercept/track. It can be a bit un-nerving as you near a station.

[bartender]

By the way, in real life and simulator...if you have the AP set for the VOR, be carful because when the t/from indicator switches, the AP tries to do a 360 degree turn to correct it. I have herd that a couple of pilots frgot about this and died trying to correct it. So that just for reference guys.

Bret
PVtPilot

[jinx]

Thanks for the information.
The FS9 Flying lessons are horrid and badly made in this respect.
Things are much simpler than the stock lessons make them out to be.

I learned both VOR to VOR and ILS approaches perfectly and unaided by their lessons, and when I tried thier ILS lesson in that fog I could not manage it amd crashed the plane.

[beaky]

The lessons are really poorly done in FS9, although the exercises given are suitable... glad to hear you're making progress without "Crazy Virtual Rod Machado" in the plane with you...