FPLN total dist unaccuracy.
Hello Ladies and Gentlemen,
Maybe someone has already noticed that fact :
Everytime a DME Arc procedure is involved or included int flight plan,the UNS-1 misses the total distance calculations !
Example : GBYD/GOBD with STAR BJ1K via KOSOM , the FMS calculates a total distance of 136NM while the real distance is 124 NM !
I attached the FPLN file and the real procedure at GOBD.
What developpers think about that ? It should be fine if You could correct that.
Thank You anyhow for your efforts for making that wonderful Q402.
Comments
Hello Diama,
To me it does not look too bad.
GBYD to D18 DS = 64 Nm
Intercept of the arc DME = around 2 Nm
Arc DME from 348° to KOSOM = 55 NM
Kosom to GOBD = 14 Nm
Total = 135 Nm
Regards,
JP
Okay Jpgmultimodal,
But the fact is the real distance is 124NM,that leads to a approx 10NM of discrepancy !
Believe me,each and every time a DME Arc procedure is included in the FPLN we get a discrepancy ! I would give 2 more CityPairs but unfortunetaly i cannot attached those FPR files ( MJS ) flight plans / routes types of files.
They fail to load !
As far as I made it out the real distance appears to be 135 Nm. How do you find 124 Nm?
Hi again jpgmultimodal,
Here i come back to you.
My ( personal ) calculations crosschecked and confirmed by both Jeppesen FliteStar and Jeppview :
1/- Distance D0 = 66 NM ( from BJ VOR -> 16 DME DS ).
2/- ARC DME 16 (DS) full Circle : Perimeter C = 6.28R .... ( Radius R = 16 NM ).
- C # 100.5 NM for full Circle = 360° ; that leads to ALPHA = 0.28 NM / DEG°.
3/- Radial R1 = 168 from DS ( beginning the ARC ).
- Radial R0 = 007 from DS ( position of KOSOM ).
- Delta Angle DA = R1 - RO = 161 DEG°.
We come to : D1 = ALPHA * DA = 0.28 * 161 # 45 NM.
4/- Distance D2 = distance from KOSOM ( start of approach IAF/IF ) to approx RWY 19 of GOBD = 14 NM.
Finally , D0 + D1 + D2 = 66 + 45 + 14 = 125 NM.
Voila !
Hello Diama,
You are right. Regarding the distance for the Arc, I put 55 instead of 45 as the result of my calculation and now I get the same result as you do.
The input to the UNS is coming from the AIRAC supplied by NAVIGRAPH and I do not know if this can be changed.
I do not have GOBD in my sceneries but I flew this ARC DME and the result looks OK so it does not affect the flying at all.
However, even this is beside the point that you made, If you plan with PFPX and enter this STAR BJ1K they do not take the ARC into account and the total FPL shows only 114 Nm which is worse when you are planning to get less than the distance actually flown.
Have a nice day,
JP