OnCourse Software

I have been monitoring Conflict Monitor for a couple of weeks now.. and my conclusion is that it deosn't seem to work at all these days. AI trafiic always seems to plough straight through my aircraft, no matter what the angle of 'attack' - or my speed. I have CM box checked and speed set to 16 in the ini options.

Here I was stationery:





.. the aircraft just carried on as if I were not there and continued to the runway. Same if I am taxiing (I keep to 15mph or slower), or if the angle is more or less oblique than in the screenshots.

Log attached... it would be good to have the CM running again, but I have no idea what else to tweak..

Thanks,

Martin

Martin, this is similar to what you have posted previously (aircraft taxiing through one another or through your aircraft) and as I mentioned, I think there is something else going on with your FS setup. I have not observed what you have described. Ordinarily, when an AI aircraft approaches a user aircraft directly in its path, the AI aircraft stops. This is controlled by FS, not PF3. I have found that if I am blocking a taxiway and am stationary, the AI aircraft will stop and not move until I do. Also, when you are stationary, the Conflict Monitor is not operating. The CM process is not active when your speed is below the threshold you have set. If an AI aircraft is taxiing through you when you are stationary, something other than PF3 is causing it. It may have something to do with your AI traffic files, or crash detection settings, or something else; I'm not certain.

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The CM process is not active when your speed is below the threshold you have set

I really don't understand, try as I might, how CM is supposed to work. I 'argued' for a long time (in this thread probably) that this being the case (above), then the speed threshold needs to be set to a low figure, so that CM will be operative unless you stop, or slow to a crawl. The general recommendation however, was that it works best at around 16, and that you stay below that speed on the ground. But from what you say, that means that so long as you are taxiing no faster than 16mph, CM won't be operating at all. (?).

When I set a lower figure though, I constantly had traffic stopping dead in front of me, not when joining the taxiway, but when we were taxiing in a line along the same taxiway in the same direction. I never understood how that might be helpful...

Whatever, I end up 'zapping' traffic way too often. Maybe I should just turn the feature off. What I really 'expect' it to do is to help pause AI traffic, no matter what speed I am taxiing (I like to do so at about 15mph, slower of course for turns), which is joining the taxiway obliquely (at whatever angle), but not to halt aircraft which are taxiing in front of me, on the same taxiway, in the same direction. I don't expect it to be able to do much about aircraft coming at me head on, on the same taxiway of course!

I can't imagine what is in my FS setup that would cause this to happen. I'll try with CM off; I can't think of what else would stop things from working in this way.

I'd also suggest you try taking a position blocking a taxiway at a busy airport and see what happens without bothering to start PF3 at all. I can't see how PF3 can be causing AI to taxi through you when you are stationary.

martinlest wrote:

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The CM process is not active when your speed is below the threshold you have set

I really don't understand, try as I might, how CM is supposed to work. I 'argued' for a long time (in this thread probably) that this being the case (above), then the speed threshold needs to be set to a low figure, so that CM will be operative unless you stop, or slow to a crawl.

Set it to 5kts like I said to you a long time ago. What you have illustrated with your images no longer happens to me at all, ever in PF3.
If you see an aircraft ahead that appears to have stopped slow down and let it accelerate away and then procede yourself. Methinks as well that you are also taxiing too fast again. Taxi at 15-20 kts only. Even on a long taxiway. Taxiing above 20kts is dangerous because the control surfaces can come alive and you just do not want that in a crosswind! And, if you are turning too fast you can exceed you undercarriage limits. Don't believe the trolls on avsim and pprune who crow about taxiing their 747's at 40kts etc. It just is not done in real life! A colleague of mine has issued two reprimands this year for speeding during taxiing. One to Meridiana and one to Air Dolomiti. Both times the speeds were between 25-30kts. Note, none have ever been issued to Alitalia. From a safety point of view they are on a par with BA!
Dave has allowed for total flexibility with conflict monitor speeds. It works for me, maybe because I observe the rules!

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Methinks as well that you are also taxiing too fast again

Youthinks entirely erroneously... I never* pass 15kts (as CM is set to 16), as I stated above:

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Same if I am taxiing (I keep to 15mph or slower),

...hence rest of your comments re. same not really relevant I'm afraid.

OK, I could try 5kts (again)... or, I could do this:

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If you want to taxi behind another aircraft at 15 knots then set CM at something above that... say 17 knots. But then remember if/when taxiing on a free taxiway your speed would have to be above 17 to ensure CM was running and preventing conflicts from other aircraft.

(that's Dave M.'s advice, by the way). Probably have to modify the numbers down a bit though. I'll go back to 5 or 6 kts again and see what happens as a starter, anyway.

* Well, never say never. I do sometimes taxi up to 20kts - but only if I have a completely clear taxiway with no other traffic taxiing at the time.

martinlest wrote:

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Methinks as well that you are also taxiing too fast again

Youthinks entirely erroneously... I never* pass 15kts (as CM is set to 16), as I stated above:

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Same if I am taxiing (I keep to 15mph or slower),

...hence rest of your comments re. same not really relevant I'm afraid.

OK, I could try 5kts (again)... or, I could do this:

Quote:

If you want to taxi behind another aircraft at 15 knots then set CM at something above that... say 17 knots. But then remember if/when taxiing on a free taxiway your speed would have to be above 17 to ensure CM was running and preventing conflicts from other aircraft.

(that's Dave M.'s advice, by the way). Probably have to modify the numbers down a bit though. I'll go back to 5 or 6 kts again and see what happens as a starter, anyway.


* Well, never say never. I do sometimes taxi up to 20kts - but only if I have a completely clear taxiway with no other traffic taxiing at the time.

Aircraft are not like cars with an accurate speedometer. Though nowadays your ground speed does show up on your display unit. That said, to see it you would have you head buried under the cowling and not able to give full attention to what's going on outside.
Non glass cockpit a/c sometimes have a groundspeed gauge but usually they rely on their airspeed indicator and experience as how fast the ground is passing by. 15kts is 17mph so pushing 20mph. 20kts is 23mph so the a/c is actually taxiing at a fair rate. Also most jet transports will taxi at 10-20kts with idle thrust (unless they are at or close to auw) with occasional application of extra power to maintain momentum as there is no direct drive to the wheels as in road vehicles. Knowing how much thrust is needed allows the crew to concentrate on the view outside the a/c
Three main reasons for not taxiing too fast are:-
1. Control surfaces including wings can become live especially in gusty weather. Making it more difficult to control the a/c on the ground and indeed the crew can be taken by surprise by a wing suddenly lifting or tail plane pushing the a/c to one side. An ATPL pilot allowing his a/c to ground loop would almost certainly be suspended by his/her airline!
2. Braking action. Some a/c will have brake temperature gauges but otherwise the crew has to calculate the braking force and subsequent brake temperature rise themselves. Indeed if an a/c has to suddenly brake to halt during taxi that can in some cases put so much heat into the brakes as to annul the take-off and thus force the a/c to taxi slowly back to the ramp to allow the brakes to cool down (which can take a significant time). The hotter the brakes get the less efficient they are and you need every nanometer of stopping distance when aborting a take-off roll. Think of how you brake when driving a car down a slope. The correct method is to periodically brake firmly and release and not constantly ride the brake.
If you have been braking hard during taxi or during your landing roll then this formula usually applies: Time= 5mins for each 1 KE in excess of 5 KE remain on chock for the whole of this time. For an a/c the size of a Super VC10 this requires a waiting time on chocks of 41 minutes after a normal landing if at max landing weight!
3. Undercarriage limitations. Most "modern" a/c have a tricycle undercarriage with some form of nosewheel steering. The nosewheel is significantly weaker than the main undercarriage as it is not designed to support the weight of the aircraft. Also a/c manuels will placard nosewheel steering angle limitations at normal taxiing speeds. Again using the VC!0 as an example the normal steering angle is 55deg. But 70deg is allowed for low speed manoeuvering. Full deflection of 70deg at 20kts will result in a nosewheel failure and could compromise the strut as well. A/c with underslung engines have the additional problem that in a turn the engine cowlings can contact the ground surface as the a/c leans over.
So what I do in PF3 is to observe what other AI are doing. If one ahead appears to have stopped I slow down and if necessary stop about 50-100metres behind him. I let him get going again and wait a few seconds before starting off to ensure that I am now outside the conflict monitor boundary thus allowing me to taxi at normal speeds.

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Aircraft are not like cars with an accurate speedometer

Really? You're too technical for me.. Who would have imagined that!! And here's me, after 16 years of FS, thinking they were just like in a car... (Actually, that's why I have a taxi monitor gauge so I know exactly what speed I am taxiing - I am keeping to about 15kts currently).

But, 'joking' aside, I am now back to the situation where aircraft in front of me keep stopping as soon as I taxi faster than 5kts (I have set CM to this again, as you suggested). I am maintaining a reasonable distance behind:



I had to stop behind this aircraft 12 times (12!) before I reached the runway. You'll see from page one of this thread that I am not alone in this frustration. OK, I could just keep stopping over and over again. After a few seconds the AI plane starts up again, but after another 15 seconds, its brakes are back on again. And so it repeats. No other AI a/c taxiing anywhere near...

It's really frustrating, and hardly realistic. I could just 'zap' it, but then I might as well turn CM off and zap everything. I hope Dave at least will be able to see that there is still something to be done in this regard.

What I don't need at this stage is another lecture on how to use FS9 - no matter how well-intentioned. Thank you for your understanding, Vololiberista!

Martin

I’m going to make a few more suggestions, although I think it unlikely I will be able to satisfy your concerns. One option is to continue to experiment with the CM speed setting. I think most PF3 users have been able to find a speed setting that works fairly well for them most of the time. Another option is to increase the distance at which you follow the aircraft taxiing ahead of you. CM has a monitoring distance of about 400 meters from your position (according to the User Guide) and aircraft more than that distance ahead of you are not monitored and will not stop. Of course, if you taxi faster than the AI, you will eventually close the distance. Maintaining a greater following distance may help. And finally, if you can’t find something that works for you, you can turn CM off entirely. None of these is a perfect solution. I know Dave has mentioned that he wants to completely revisit the topic of AI interaction in the future, but it’s a complicated matter and may not happen for a while.

HI Dan.. thanks. I think I may try with CM off again. I feel that I was maintaining quite a large distance behind the a/c I was following. I can try some other values in the CM box, but I am, not sure it's going to make much odds..

Yes, this must be a complex thing to get right, from Dave's point of view. On the other hand, there is a lot of complex stuff (it seems to me!) in PF3 that works really well, so if anyone can get this right, I am sure Dave can!

This really brings me full circle with CM, right back to what I said weeks ago. I still don't see the point of having a monitor that causes a/c to stop when they are directly in front of you. It can't help when a/c are coming at you head on on the taxiway, if they stop it just defers the 'collision' for a few seconds. If they are heading in exactly the same direction on the same taxiway, then there is even less point, it seems to me.

Ideally (unless someone can explain why I am wrong here), the CM should operate in roughly the green zone here and ignore a/c in the red...



Then, surely, all would be fine? Don't if it's achievable, technically, of course..

Thanks again,

Martin