known ETO over next WPT

[N55E008]

Hello.

It seems that the ETO over next WPT on the upper right corner of the ND is not calculated correctly.

E.g.: as on a flight today, distance to next WPT was 64NM with GS of 432. Makes a total time of 9 Minutes.

The ETO shown on the ND was however 13 Minutes to go from actual time, so a gross error of +4 Minutes.

On another leg, the Distance to the next WPT was 251NM at a GS of 431. Makes a total time 35 Minutes. When 251NM from next waypoint the ETO on the ND differed by +22 Minutes from the actual Legtime...

Anyone else experiencing this?

Edit: when approaching the next WPT, ETO on ND is subsequently updated and is finally down to the correct value when overfyling the WPT.

Best regards

Edited April 15, 2018 by Morten

[N55E008]

I've performed a number of trials again, and at least on Xplane 10 this seems to be an obvious bug.

On the image shown below, distance to next WPT is 330NM, GS is 331kts, makes a total time of 60 Minutes. Present time was 11:32 as shown on the clock, so ETO over next WPT should be 12:32.

Instead, 12:43 is displayed as ETO on the ND... ( +11 Minutes ).

Especially on longer legs ( 300NM and more between two Fixes ), the observed calculated ETO for the next WPT differed by up to +25Minutes when starting the affected leg.

As described before, the ETO is subsequently updated along the affected leg and becomes bit by bit more accurate when approaching the next active WPT.

So probably this thread should be moved to the bug section.

Best regards

Edited April 15, 2018 by N55E008

[Litjan]

The estimated time over the next waypoint is calculated with the ground speed calculated by the FMS dependent on speed planned - just like in the real aircraft. So it is more or less independent of the ground speed indicated.

The real plane will calculate the waypoints downstream with the FMS speed (converted to ground speed by applying wind entered either in the LEGS page per leg, or by the cruise wind or the wind component) - wind is not calculated by the IXEG yet. The real plane will also consider actual wind for a small portion of the current leg.

The estimates calculated in our IXEG simulation are very rough for now - we hope to improve them along with further refinement to our FMS calculations.

Jan

 

Edited April 16, 2018 by Litjan