ILS problems

[wmeimes]

I'm having problems with some aircrafts that after being clearly taken in the glide slope, suddenly start to climb and lose it, generally very close to the runway. They never lose the horizontal axix, just the vertical one.
The question is. Is the problem in the aircraft cfg or whathever, or in the airport, or maybe in the way I'm setting speed to the final approach?
Now the problem was with a posky 742 , and I see that heavies present the glitch more often. Is it there any relation with the bird's size/weight?

Thanks

Walter

[Leo112]

Well first of all is this happening with add-on airports or default? Second is all your aircraft have this problem?

Another thing to understand is ILS unless it's CAT3 isn't designed to autoland an aircraft all the way down to the ground. What you should be doing most of the time is let the autopilot get you positioned on the Glide Slop and Localizer meaning your in a nice decent at 145 knots (depending on weight), when you see the runway you disconnect the autopilot and autothrottle and manually land the aircraft. That's how it's supposed to be done. You should already have lowered your gear and set flaps appropriately for landing while under the AP so all you need to do fly the aircraft down and flare before touch down. The aircraft is already trimmed perfectly to where a 10 year old can do it. I rarely if ever expect ILS to fly me all the way down to the runway unless visibility is 5 miles or less. In those conditions many real world operations divert anyway...

For the record developers usually have to specially program their aircraft to do automated ILS landings properly. Ready For Pushback's 747-200 comes to mind here. If they don't it's possible to do an ILS landing you just slam into the runway harder than you should which is very unrealistic. I guess Aces always assumed simmers would take the time to learn how to land aircraft. I wouldn't be surprised if there are ILS discrepancies throughout Flight Simulator because it should be an 'AID' not a 'crutch' (as is the case in the real world). Not trying to berate anyone here but if you guys can only autoland using the ILS then you need to get passed that and learn how to properly fly and land the aircraft.

[wmeimes]

Leo

Thanks for the attention. Look, I tryed to land the 744 posky at Boeing Field (dafault) in Seattle. As it happens to the the 742, it misses the ILS glide slope in the final phase of the landing and starts climbing . Accordingly, I use ILS to get close to the runway, but usually land the bird manually.
Then I tryed SGA MD-80 in the same runway, and it lands fine. So the problem seems to be the model, and I ask what in the aircrafts cfg creates this problem? Or is it a glitch inherent to the model?

By the way, see if you can help me with ATC. I left Albany to JFK, in a short ride to make a busy sunset approach under bad weather. Then , close to the apple, ATC sent me west far away from JFK and forgot me. I asked for another approach, and was left flying north for about 15 minutes. A little more and I'd be back in Albany. Do those things happen in ATC?
Another in ATC: in Congonhas (Sao Paulo) I was stopped short at runway 17L, waiting for take off clearance (SBSP has an intense traffic), whan the ATC lady authorized a TAM A320 behind me to take off. It went trough me and left. Do people drink in the control? Is this a traffic (Amazing Traffic installed) or ATC?

Thanks
Walter

[Leo112]

Leo

Thanks for the attention. Look, I tryed to land the 744 posky at Boeing Field (dafault) in Seattle. As it happens to the the 742, it misses the ILS glide slope in the final phase of the landing and starts climbing . Accordingly, I use ILS to get close to the runway, but usually land the bird manually.
Then I tryed SGA MD-80 in the same runway, and it lands fine. So the problem seems to be the model, and I ask what in the aircrafts cfg creates this problem? Or is it a glitch inherent to the model?

By the way, see if you can help me with ATC. I left Albany to JFK, in a short ride to make a busy sunset approach under bad weather. Then , close to the apple, ATC sent me west far away from JFK and forgot me. I asked for another approach, and was left flying north for about 15 minutes. A little more and I'd be back in Albany. Do those things happen in ATC?
Another in ATC: in Congonhas (Sao Paulo) I was stopped short at runway 17L, waiting for take off clearance (SBSP has an intense traffic), whan the ATC lady authorized a TAM A320 behind me to take off. It went trough me and left. Do people drink in the control? Is this a traffic (Amazing Traffic installed) or ATC?

Thanks
Walter

First off I must concede and say there must be something going on with the Posky model. It's good to know you know how to fly the aircraft. As far as what's causing it not to catch the GS is how Posky chose to model their birds. They have such slow lag times trying to model the heaviness of the birds it affects how it captures exact headings. What you need to do is go into the 'aircraft.cfg' file and tighten up the elevator sensitivities. I wrote them about this but their stead fast on their approach. I have their 737NG series of aircraft in which I use the PMDG 2D panel (the PMDG VC is murder on my system). I had to adjust not only the elevator sensitivity but also the aileron sensitivity until the plane captured the ILS/GS correctly. This should solve your problem with any Posky bird. Just remember you'll see this with many of their aircraft.

As far as ATC, well that's common sometimes depending on how you setup your flight plan. The way to make this stop happening is when you first build up your Flight plan in the FS menu you have to be mindful of your waypoints. The tail tail sign you'll experiance ATC forgetting about you is if your very first waypoint is too close to your departure airport and your last waypoint is too close to your destination airport. Be mindful of this when FS builds the flight plane for you. Delete the first and last waypoints (not the departure and destination airports mind you) if need be before you save your flight plan."

Another bit of info I'll give you before I start charging is always manually build your waypoint for long haul flights. Letting FS do it will create almost 50+ waypoints that you manually have to punch in the FMC if your using one of those type of add-ons. Let FS create a GPS point to point flight plan then go in and drag the lines to various waypoints along your route. I always (for example) setup a few waypoint out of Heathrow far enough out I don't have the problem you mentioned above. I set a few over the water just south of Greenland and a few on my way in to KMSP. I end up with 15 waypoints at the most if that. A rule of thumb is to set waypoints well outside the airspace ring of the departure and destination airports. :)

[wmeimes]

Thanks Leo. I'll start working on waypoints. Regarding elevator sensitivities in aircraft config, which values can I use and where? Is it this spiel?(Copied from posky 747 cfg)

[flight_tuning]
cruise_lift_scalar = 1.0
parasite_drag_scalar = 1.0
induced_drag_scalar = 1.0
elevator_effectiveness = 1.0
aileron_effectiveness = 1.0
rudder_effectiveness = 1.0
pitch_stability = 1.0
roll_stability = 1.0
yaw_stability = 1.0
elevator_trim_effectiveness = 1.0
aileron_trim_effectiveness = 1.0
rudder_trim_effectiveness = 1.0

Regards Wallter

[xxmikexx]

In Les' absence ...

Elevator sensitivity is controlled by the elevator effectiveness line. Higher value increases sensitivity. However, the FS autopilot controls pitch via elevator trim so that's the line you will need to change.

I'm not 100% certain of this but I am 98% confident.

[Leo112]

Sorry I'm late guys:

These two lines are what you need to tighten up to get the autopilot working correctly. Play around with the settings here and you should eventually get better results when capturing the ILS.

elevator_effectiveness = 1.0
aileron_effectiveness = 1.0

:)

[xxmikexx]

You're right about the ailerons, Les, but I say that given the way the autopilot works, it's the elevator_trim_effectiveness line that counts.

So, wmeimes, try it Les' way first. But if you're still not getting enough elevator responsiveness, try it my way.

Either way, I personally would like to know the outcome.

[adamjosiah]

Uhm, this may be over obvious but from my experience, the only reason why an A/C physically refuses to land at the last minute is because the throttle is too high. And different A/C will behave differently at a given percentage of throttle. Heavies with more engine power may actually hold altitude longer at low throttle than some of the smaller A/C with less powerful engines.

So whether it be a control (joystick) problem, a config file problem, or an autopilot problem (make sure your disarming your auto-throttle properly)... it could very well be throttle related in my oppinion.

[wmeimes]

Gentlemen

I see you'd like to know the result of your advices, and today I'm going to take care of it. I also have a CLS A300 that began to show this unproper behavior. Smaller aircrafts, as PMDG 737 NG or Project Airbus A320 perform fine, so it is obvious that the problem seems to be related also to throttle adjustments and elevator sensitivity and due to inercia questions, all seems to be more critical among heavies. Anyway, thanks for the interest you're showing on my spiel.

Regards Walter

[Leo112]

Uhm, this may be over obvious but from my experience, the only reason why an A/C physically refuses to land at the last minute is because the throttle is too high. And different A/C will behave differently at a given percentage of throttle. Heavies with more engine power may actually hold altitude longer at low throttle than some of the smaller A/C with less powerful engines.

So whether it be a control (joystick) problem, a config file problem, or an autopilot problem (make sure your disarming your auto-throttle properly)... it could very well be throttle related in my oppinion.

Your right as is the case with the payware Sky Simulation's MD11. Something is diffidently going on with the throttle there. Depending on the model your right it could be a combination of all you mentioned. Here's an example of what I had to do with these models (Posky's 737NG series):

[flight_tuning]
cruise_lift_scalar =1.000
parasite_drag_scalar =1.201
induced_drag_scalar =1.501
elevator_effectiveness =1.000
aileron_effectiveness =1.100
rudder_effectiveness =1.000
pitch_stability =1.000
roll_stability =1.000
yaw_stability =1.000

elevator_trim_effectiveness =0.751
aileron_trim_effectiveness =0.501
rudder_trim_effectiveness =0.501

Mike looks like you were right after all. I miss spoke earlier as I was at work. Now I'm home I can see exactly what worked to correct Posky's choice in making the controls too sluggish to simulate heaviness of the aircraft... Walter never mind what I said earlier, start here and see what happens but do remember the adjustments here are for the 737NG series not the 747. This is a great place to start though. :)

[xxmikexx]

You're right too, Les.

Knowledge of elementary aerodynamics is the key to knowing which parameters to experiment with. You deserved to be right about the elevator, it's just naive FS internal software design that has the FS autopilot elevator channel controlling trim instead of the elevators all the way to touchdown. The autopilot should be doing what real world pilots would do -- use the elevators at relatively low airspeeds, use the trim at relatively high airspeeds.

Some addon aircraft, like the Level D 767, appear to bypass the FS autopilot completely. For such addon designs, you'd be exactly right that it would be the elevator_effectiveness variable.

:)

[wmeimes]

Well gentlemen.

The posky 742 is useless, autothrottle doesn't work, numbers in AP settings are too small to read BUT... I tweaked the settings under to the CLS A300 600 and could make at least two (almost)perfect landings , one of them regaining command of the bird already over the runway due to blinding severe blinding weather. Very good.

[flight_tuning]
cruise_lift_scalar =1.000
parasite_drag_scalar =1.750
induced_drag_scalar =1.750
elevator_effectiveness =0.800
aileron_effectiveness =1.000
rudder_effectiveness =1.000
pitch_stability =1.200
roll_stability =1.000
yaw_stability =1.000
elevator_trim_effectiveness =0.800
aileron_trim_effectiveness =1.000
rudder_trim_effectiveness =1.000

atc_type=AIRBUS AIRCRAFT
atc_model=A306R

So as you can see, I dimmed elevator effectiveness, increased pitch stability, and dimmed elevator trim effectiveness. In the second landing it seemed to be a little lasy to retain up the slope in the last stages of the landing, but I have to review carefully aproaching speeds to A-300 .I was coming in at the final at 150 Kias, which I confess is a pure guess. But anyway this seems to be the way. Thank you all!