Descent Angle and V/S

[Boyington]

In the Jeppesen Approach charts, under the profile view the required vertical speed to remain on profile for the respective descent angle is mentioned. But for the same descent angle and ground speed the vertical speed mentioned sometimes varies.
For example in Kuwait for chart 18-1 with a descent angle of 3 degrees the V/S required is 637 for G/S of 120 kts but for Male Airport (VRMM) chart 11-1 with a descent angle of the same 3 degrees and GS of 120 kts the V/S required is 646
It beats logic. Can someone please explain?

[Goldenrivett]

It beats logic.
Neither is set exactly at 3 degrees.
There is 0.04 degree difference between them and they couldn't be bothered to publish the descent angle to the second decimal place.

[RAT 5]

I stand to be corrected, but Jeppeson is a publishing house of data sent to them by the individual Airports and their respective AIP's. They do not produce self-claculated data. Info told to me years ago????

[underfire]

Rat,

As far as I am aware, Jepp does calculate the information. From errors noted from posts on this board, Jepp has recalculated and revised several plates.

In the procedure design world, we must validate the coding of the procedures and waypoints on the AIRAC cycle, and there are always waypoints and runways ends that are incorrect. Curved fligthpaths are always a negotiation.

In addition, there is quite a bit of the world where the AIP is not standardized to the standard datum. Jepp has to do the conversions for these datums.

[Sydy]

I am still to see a pilot that can maintain precisely 646fpm instead of 637fpm...

But the discussion is valid...