I would suspect that make and model of autopilot might make a difference in reaction?When VOR navigation was the primary navigational mode, the airliner autopilots would automatically switch from VOR/LOC to HDG HOLD mode when near the VOR and switch back to VOR/LOC mode after passing the VOR.Stamatis

Hello Stamatis:In your reply you say the airline autopilots would automatically switch from VOR/LOC to HDG HOLD mode. My question still remains why does FS9 not do the same thing. Making this a pilot manual control change in todays computer "age" makes no sense to me.

Stamatis:Good try, but I think you'll have to offer proof of this one. Which airlines, or airliners? Which autopilots? Which models? If what you think or suspect here were true, then the airplane might do a 180 degree turn over the VOR station. It might turn away from the airport during an ILS approach. What if the heading bug was last positioned to the reciperical heading? No, sorry, but I don't believe this is an acceptable answer in this form. And, are you saying VOR navigation is no longer the primary navigational mode? Who says? Since when? I don't know and really want answers here if you do know these facts. I don't have them as of yet. Is GPS, Loran, RNAV the current primary navigational mode? Please tell me.

Stamatis:Good try, but I think you'll have to offer proof of this one. Which airlines, or airliners? Which autopilots? Which models? If what you think or suspect here were true, then the airplane might do a 180 degree turn over the VOR station. It might turn away from the airport during an ILS approach. What if the heading bug was last positioned to the reciperical heading? No, sorry, but I don't believe this is an acceptable answer in this form. And, are you saying VOR navigation is no longer the primary navigational mode? Who says? Since when? I don't know and really want answers here if you do know these facts. I don't have them as of yet. Is GPS, Loran, RNAV the current primary navigational mode? Please tell me.

I just got the pertinent line from my autopilot manual (stec):"If the Heading bug is within 5

My $0.02 on this discussion ...Most lightplane autopilots (like the KAP-140 in the C172/C182) have absolutely no knowledge of the NAV source you're using. The only connection they have for NAV is to the CDI needle on your primary NAV display and possibly the NAV warning flag. All they're really doing is watching how the CDI moves and adjusting course to keep it centered. If they pay attention to the NAV flag, they usually revert to wing leveler mode if the NAV source is lost.How the autopilot responds to station passage really depends on what the CDI does. The autopilot response is damped to prevent it from following rapid fluctuations, but as you approach station passage and the needle swings to one side the autopilot will begin to follow the needle. As you enter the "district of disorder" (sorry .. couldn't resist) most indicators switch from a "To" indication to "Off". Either the autopilot will disconnect NAV mode or if it remains engaged will continue to follow the CDI, which will typically center if no NAV signal is present.The proper method of operation IS to switch to HDG mode whenever the NAV source is lost or is unstable (like when approaching the VOR), as an earlier poster suggested. It may not be state-of-the-art, but it is real world when it comes to light aircraft.As far as bank, autopilots are typically restricted to no more than 30 degrees of bank. The KAP-140 uses the turn coordinator for roll input and makes all turns more than about 10 degrees at standard rate. So even if the autopilot chases the needle, it should never get you into a steep bank. (although I suppose without altitude hold, you might spiral if you don't correct for loss of lift in the turn)

I did a quick test flight last night in the default C182. As I got close to the VOR, the needle swung out to the right just before I lost the signal. The plane started to bank to the right, but it lost the signal. The autopilot did switch off NAV mode, but it stayed banked. It seems that MS took out the wing levler from the default autopilot.So I'm guessing what happened to the original poster was that as he crossed the station, his plane began to turn and then lost the station. The autopilot probably switched out of nav mode, but since there is no loger a wing levler, the plane didn't return to level flight and kept turning.One thing you need to keep in mind is that the autopilot is an aid to the pilot, it's not ment to fly the plane by itself. You still have to keep up you instrument scan and monitor what the autopilot is doing.

You are on the right track, but, the MS Mooney Bravo did stay level. The other aircraft did stay banked and did not recover on their own. It is apparant that there is a discrepancy between the Mooney and the other aircraft? As for looking after the autopilot, which is as you say, an aid, all you say is right on, but that does not solve our problem completely. And the pilot is sometimes busy with other duties right at the instant of a station crossing, and this does need to be addressed. Sometimes there is coffee to drink, charts to read, ATC to deal with. And don't forget the surly passengers who need attention, or the many other distractions. Some pilots even have to deal with a bit of l'amour from the stews. And don't forget the ones (pilots) that nap.

This is a good two cents worth. Thanks. very well explained indeed. Now all we have to do is figure out how to fix the aircraft in the sim to make them do what they ought to do when they cross a station in NAV mode.

Which airlines, or airliners? Which autopilots?Example: MD80 Swissair (early ones, pre FMS era) I believe they were Sperry Autopilots but it could be Collins as well, can't remember for sure.As you got near the station, VOR mode reverted to HDG HOLD (not HDG SEL, so your heading bug could be anywhere, it wouldn't matter)I have witnessed this with my own eyes :-) If what you think or suspect here were true, then the airplane might do a 180 degree turn over the VOR station.Where did you get this idea from? It would continue on present heading and then, once away from the VOR station, it would track the selected radial outbound.Assuming you were flying a course of 090 inbound the A/P by selecting a course of 090 in your HSI. The A/P will be tracking R-270 inbound. Once passing over the VOR the A/P would track Radial 090 outbound. Your course would remain 090, as before. The TO/FROM flag in the HSI would switch from TO to FROMIt might turn away from the airport during an ILS approach.No way, LOC traking is different than VOR tracking.And, are you saying VOR navigation is no longer the primary navigational mode? Who says? Since when? Is GPS, Loran, RNAV the current primary navigational mode? Please tell me.Yes, RNAV is compulsory for airliners. I do not remember since when.The skies are filled with Area Navigation Airways which cannot be tracked without RNAV equipment, because these airways are not defined by VOR radials.I am not aware of what is the status with GA aircraft.Best RegardsStamatis

Stamatis: Thanks. Glad to get this one. I see what you are saying on Heading Select, and the difference with Heading hold (I think so anyway). And as for RNAV having become the primary mode of navigation , I can believe that. I was deepy involved with RNAV myself and flew it routinely on almost every flight in King Airs between 1975 and 1980. I had the charts but filed direct most of the time. We could go from KLEX to KMIA or KFLL (What was Pompano Beach?) with no complaints or changes from ATC at the time. I used a Collins unit that ran to $ 55,000.00 US dollars way back in 1980 in a King Air 200. That's a while back. So for me, since then, many new navigational techniques and new kinds of equipment might have come along and become dominant. I like the GPS these days. But would be good to get Microsoft to do something to fix this problem in the sim. I have a brand new medical certificate and am about to get active again so need to learn GPS now. But let's fix the VOR problem in FS9.

>Yes, RNAV is compulsory for airliners. I do not remember since>when.>The skies are filled with Area Navigation Airways which cannot>be tracked without RNAV equipment, because these airways are>not defined by VOR radials.>>I am not aware of what is the status with GA aircraft.>Actually, while RNAV is now ubiquitous in airlines it is not strictly required (see FAR

North American airspace is still based on VOR airways. Even with RNAV capabilities, you're usually following the highway in the sky based on VOR-to-VOR navigation.Hi!Yes, compulsory may be the wrong word to use.But try flying without being able to use area navigation routes in Europe and your company could be out of business before you realize it :-)Just browse a Hi-Altitude Enroute Jeppesen chart for Europe, and bear in mind that all Airways with a basic designator L, M, N, P, Q, T, Y, Z are area navigation routes. (I believe that since these designators are ICAO Annex 11 the same must apply to US Airways as well but am not sure)And of course I never said VOR's are decommissioned, far from it.But some aircraft, (744 for example) do not even include independent NAV tuners any more! Everything is done via the CDU.Stamatis

Yes, compulsory may be the wrong word to use. But try flying without being able to use area navigation routes in Europe and your company could be out of business before you realize it :-)You are indeed correct, sir! The same holds for airlines in the U.S. (even on commuter turboprops, most have an FMS sitting between the seats) Part 121 (scheduled air carrier) rules in the US require that routes be approved and that the plane has nav equipment sufficient to navigate the route (wiggle words if I ever heard them :)). If the carrier uses RNAV routes, then RNAV equipment is mandatory.Just wanted to point out that, in spite of some pretty advanced navigation capabilities in today's aircraft, the system's least common denominator is still the good ol' VOR. Airspace and airway design have to continue to accomodate point-to-point VOR navigation until such time as the FAA can migrate the system to satnav. Makes for some interesting compromises in today's system.BTW, US airways are mostly J and V routes in the lower 48 although you do see some Q's in coastal and mountainous areas.Happy flying!

Wow. Old time, she is a flying. All this made me look at my Low Altitude Charts I bought just to fly my sims: Professional Pilot, Flight Unlimited II, and III, and Fly, FLY2k, Fly II, MS 2000, 2002, and 2004. I thought I was only a tad out of date. The date on my Low Altitude VOR charts: May, 1999. So you know why I was thinking in VOR terms.