Unable Pattern Work

ATC
10

Strong winds aren’t a factor.

image
image1334×750 143 KB

Credit: Infinite Flight Youtube Channel

Broken and overcast are the two sky conditions you want to keep an eye out for, if it is Broken or Overcast at or below 2000ft, then you deny pattern work. Now if one or both conditions are met (low visibility or low cloud cover) then there is no pattern work allowed.

  • IMC (Instrument Meteorological Conditions) = no pattern work.

  • VMC (Visual Meteorological Conditions) = pattern work is allowed.

An example of a low visibility metar would be at KISP, right now.

KISP 041256Z 36011G19KT 1 1/2SM R06/6000VP6000FT -RA BR BKN006 BKN012 OVC027 11/11 A2980 RMK AO2 SFC VIS 3 SLP091 P0002 T01110106

I have highligted the portion that realtes to the visibility and cloud cover.

  • 1 1/2sm means that visibility is 1.5sm, which is below 3sm, it’s IMC so there will be no pattern work.

  • BKN006 BKN012 OVC027 means that the clouds are Broken at 600ft, Broken at 1200ft and Overcast at 2700ft. It’s broken at 600ft, IMC, so no pattern work.

Another example is from 4hrs ago at KISP.

KISP 040945Z AUTO 05007KT 4SM RA BR SCT006 OVC012 11/11 A2980 RMK AO2 P0008 T01110111

  • Now visibility is at 4sm, which is above 3sm so you can allow pattern work as you think it is VMC.

  • As you can see though it is overcast at 1200ft, which is below 2000ft so it cancels out the fact that the visibility is above 3sm. No pattern work allowed, it’s actually IMC.

The same thing can be flipped, the cloud ceiling could be above 2000ft and you’re fine, but if the visibility is below 3sm then you can’t allow pattern work.

Hope that helps!

3 Likes