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BFM/FAM Flight plan points errors??


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Hi guys, trying to complete the BFM campaing but I noticed that in pdf files, flight plan radials are not correct, or at least the same as I measure in the ME...example:

 

APEX PDF:

 

LSV 025 09 TACAN 12X

 

APEX Meassured in ME:

 

LSV 039 09 TACAN 12X

 

 

This is a significant deviation in angular meassurement right??:huh: what am I doing wrong?? Its not the same problem as the other thread btw, as Im only talking about angles...

 

thanks!

Take a look at my MODS here

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What you measure on the map (in the mission editor) is the track over the ground related to the true noth pole (map north)

Your navigation in the cockpit is based on the compass and HSI. Both of them points towards magnetic north pole. The difference between true and magnetic pole is the variation. Variation depends on your position. According to the landing charts variation for Nellis is 12.3° east.

 

So both is correct.track over ground is 037°, but radial is (037°-12°) 025. below is the way you should do the math:

 

(Track over ground) 037

(+-wind correction) 0

True 037

+-Variation -12

=Magnetic 025

+-Deviation

=Compass

 

(Add westerly, subtract easterly)

Happy flying

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TACAN ground stations have a published real world tolerance of +/-1° at 3.75km (~2nm), per the FAA. Per USN, TACAN airborne receivers have a tolerance of +/-4° of the selected radial for IFR flight. This matches the FAA required tolerance of VOR receivers for IFR flight by the way (14 CFR 91.171).

 

To put those tolerances in perspective, use the 1 in 60 rule of thumb. 1° of offset equals 1nm in lateral position when 60nm from the station. So stacking tolerances between station and reciever, you could be in the neighborhood of 5nm to either side of your displayed position 60nm from LSV and still be within the IFR tolerances of the TACAN system.

 

Perhaps the DCS waypoints do have some errors, but it appears that they are within real world TACAN navigation tolerances.

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  • 3 months later...

Campaign manual has a page with a listing of all TACAN points and their magnetic deviations - LSV for example is 15 degrees. I take it that when you look at the map, you would need to add 15 degrees to whatever radial you are being shown. That, or you would need to subtract 15 degrees from the radial shown on HSI to match waypoints on the map...

 

P.S. I just got the campaign, so I did not get to fly it yet, but this is my understanding of how it works and by looking at the campaign manual charts/waypoint positions.

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