What do Sussex, NJ and Deadhorse, AK have in common?

When required to make this altitude correction, pilots must also inform ATC so that the controller can ensure appropriate vertical separation is applied between known traffic. Be sure to announce where and how much you will be applying the correction factor. These corrections should not be applied while being radar vectored.

Once the FAA triggers a change through the National Flight Data Digest (NFDD) office, government AeroNav and Jeppesen IAP charts will display a Snow Flake and notes on the chart (Briefing Strip for Jeppesen charts). If the temperature is warmer than the published value, no correction is necessary. Until all of the affected IAPs are updated with the annotation, refer to the current NOTAM for accurate guidance.