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Incorrect Ceilings

Open CaptainBandages opened this issue 3 years ago • 3 comments

ATIS reporting incorrect ceiling in 2.7. Select a Low Overcast And Rain preset 3. Reports ceiling at 19200' when ceiling is at 6000'.

CaptainBandages avatar Apr 22 '21 18:04 CaptainBandages

Thanks for the report! Low Overcast And Rain preset 3 is an interesting one.

It has three layers:

  1. 1680m to 5880m
  2. 5880m to 7140m
  3. 10080m to 11340m

The current implementation classifies them as follows:

  1. Scattered
  2. Broken
  3. Few

For the ceiling in an ATIS report, I've read somewhere that only Broken and Overcast layers are considered, which is why it currently reports the second layer as the ceiling (first one is classified as scattered).

The possible mistakes I see here are:

  • "that only Broken and Overcast layers are considered" might be wrong
  • This might also be a special case, because layer one and two are basically one consecutive layer (first ends at 5580m and second starts at exactly the same altitude).
  • The first layer is possibly classified incorrectly and should be broken instead of scattered.

As a reference, this is the first layer if I remove the other layers and the rain for better visibility:

image

What would you say are the mistakes here?

rkusa avatar Apr 23 '21 21:04 rkusa

Screen_210425_111607 Here is what the ME classifies the layers as. It reports the first layer as OVC. ATIS' will include all visible layers.

The first BKN or OVC layer is classified as the ceiling. But they will report all layers that the observer can see from the ground.

They are also cumulative so if you have the first layer as 2/8's (FEW) + 3/8's (SCT) The second layer will be reported as the BKN. If there was another layer above at 3/8's (SCT) it will be reported at OVC. So in my example the ATIS will report FEW at x alt, ceiling Broken x alt, and Overcast at x alt.

CaptainBandages avatar Apr 25 '21 18:04 CaptainBandages

Thanks for the info, I'll see how I can incorporate this into DATIS 👍

rkusa avatar Apr 30 '21 11:04 rkusa