The FAA published InFO 15002 last week detailing required cold-weather aircraft altimetry procedures to be used during certain instrument approaches highlighted in the Cold Temperature Restricted Airports. Compliance with the corrections, designed to ensure obstacle clearance, becomes mandatory September 17. Beginning March 5, an -XX°C snowflake icon will be added to approach plates to indicate that a cold temperature altitude correction is required when the reported temperature is at or below the figure specified for that airport.

The new temperature corrections are separate from those published on Rnav approaches. Temperature restrictions on Rnav approaches for lateral navigation (Lnav)/vertical navigation (Vnav) minimums must also be followed, even if the temperature is warmer than that associated with the “snowflake” icon. Pilots—not ATC—are responsible for applying altitude corrections. Pilots must advise ATC when these corrections are used on the intermediate and/or missed approach segment, but they are not required to mention correction for the final segment.