I'd like to know what parameter determines where AI aircraft touchdown on a runway. Is it the glideslope, localiser or some other configuration in FSX.

 

Thanks

Hi Chris,

I found a utility called Good Landings that shows the parameters - http://simviation.com/1/browse-Utilities-65-0.

 

Best regards,

Jim

I'd like to know what parameter determines where AI aircraft touchdown on a runway. Is it the glideslope, localiser or some other configuration in FSX.

 

Thanks

 

The answer is some other confiquration in FSX.

 

The Localizer and GS are owned by the runway and only gives the User Plane the alignment and touchdown point of a runway.

 

The AI Plane has a 1st code that is embedded in each runway texture which is called the TD (Touchdown Zone). The AI Plane targets this TD from the FAF if the Runway has a ARINC 424 ILS Approach code in the FSX database.

 

You have to start with a standard. That means select a runway about 8000 ft long that has a stock ILS. A stock ILS will normally have a stock full ILS Approach in the Airport records of the compiled stock Airport bgl. Using the stock FSX B737 as a AI Plane you will see the TD is about 1000 ft down the runway at the 2 solid bars.

 

Now you can start looking at 3rd party AI planes. Each 3rd party AI plane get tweaks done to the FD (Flight Dynamics). These tweaks can cause the AI plane to land short with alot of braking or land long (float along the runway) which can pass the TD zone and touchdown long. The ideal tweak would be to try and make the AI Plane TD at the proper runway location that has the target embedded.

 

The following code is the instructions given to any AI Plane based on the Approach Code and landing at KATL runway 09 Right.

 

 

<Approach

type="ILS" <<<<<<<<<<<<<-------------- ATC says fly the ILS

runway="09"

designator="RIGHT"

suffix="0"

gpsOverlay="FALSE"

fixType="TERMINAL_WAYPOINT"

fixRegion="K7"

fixIdent="BURNY" <<<<<<<<<<------------------ turn on runway heading (30 degree offset) before crossing this FAF T_Waypoint

altitude="4000.0F" <<<<<<<<<<<<<------------- overfly FAF (BURNY) at 4000 ft.

heading="89.780003" <<<<<<<<------------ AI Plane flys True runway heading +- .02 for left/right turn direction if it goes missed

missedAltitude="4000.0F"> <<<<<<<----------- If the AI Plane goes missed climb to 4000 ft.

 

The FAF (in this case) BURNY is normally set per Lat/Lon to give the GS a 3.00 degree slope. AI planes are also hardcoded to fly the ideal 3.00 degree slope to the TD Zone in the runway texture.

 

Poorly written Flight Dynamics can actually fight with the hardcoded 3.00 degree slope. On a ILS approach the AI Plane can be seen bobbing, dipping up and down, falling through the 4000 ft hardfloor when the gear comes down, land short on grass, roll to the runway, plus many other issues.

 

The written instruction in the ILS approach code can actually assist a poorly written set of FD's and help the AI Plane land. Many runways do not have a stock ILS or ILS approach code so the AI Plane must fly and set of hard code rules and adjust for the 3.00 slope.

 

Allways test your AI planes landing characteristics with a ILS approach code and then test for a runway that does not have a ILS approach code. This should be done in clear weather so if a ILS does not exist the ATC engine will not look for a lesser precision type approach.

 

hope this helps

 

jim

Hi Jim:

 

"hope this helps"

 

It certainly does Jim. I knew someone out there would have the answer to this and I thank you for responding. I also placed this question with a more detailed account on FS Developer, to which you answered as well. At least now I know it is not the FT KBOS AFCAD and, it is what it is.

 

Chris

Hi Jim:

 

"hope this helps"

 

It certainly does Jim. I knew someone out there would have the answer to this and I thank you for responding. I also placed this question with a more detailed account on FS Developer, to which you answered as well. At least now I know it is not the FT KBOS AFCAD and, it is what it is.

 

Chris

 

Chris

 

If you are still reading this post --------

 

There is a slight chance it could still be the KBOS AFCAD you are using. There is a simple way to know. Make sure that the default ATC approach controller says Expect ILS 04 Right and the approach controller says cleared for the ILS 04 right contact Tower .

 

The key here is the approach controller is saying ILS. That speech is coming from the code I show in my above post and not what is actually part of the runway ILS. When the approach controller says ILS that means there is both a Localizer and a GS and the FAF altitude is in use.

 

Years ago all we had was Lee Swordy's AFCAD utility. The AFCAD compiler made sure that all the stock approach code was protected and could not be tampered with. Today we have multiple type AFCAD utility's and each one can damage the approach coding in the database when others create airport AFCADs.

 

Let me also stress, DO NOT use a 3rd party ATC program when checking the validity of the default approach coding. These type programs inject themselfs into FS from the outside in and DO NOT understand all the internal weather, runway score, runway length, speech, weight restriction, non-precision approaches (11 non-precision +1 precision) and the way the .dll Engines work together as one set of instructions.

 

If the approach controller at any time says fly the Visual for runway 04 Right there is a problem.

 

jim

Thanks Jim. That is GREAT info to know. I do not have a 3rd party ATC program, as I use the FSX default ATC, so that defining element can be eliminated. I will set up a flight to KBOS and will carefully listen to ATC. Will let you know.

 

Best regards,

 

Chris

Hi Jim:

 

I did an IFR flight into KBOS using the FSX ATC and the instructions from ATC were "Expect Vectors....." and not "Visuals" so I guess ATC is OK.

 

Chris