AIM ¶ 7-3-4 — Cold Temperature Airports
AIM 7-3-4 explains Cold Temperature Airport procedures: snowflake icons, altitude corrections, and ATC reporting for safe instrument approaches.
Cold Temperature Airports (CTAs) are airports where extremely low temperatures can cause your altimeter to read higher than your actual altitude, putting you at risk of losing Required Obstacle Clearance (ROC) on a published instrument approach.
The FAA has identified specific airports where this is a concern. Here's what you need to know:
- Identification: CTAs are marked with a snowflake icon (❄) and a temperature limit in Celsius on U.S. Government IAP charts in the Terminal Procedures Publication (TPP).
- Current List: Found on the FAA's digital TPP website, listed by ICAO code, airport name, temperature, and affected approach segment(s).
- Airport Criteria: Risk analysis is only performed on airports with at least one runway 2,500 ft or longer. For shorter runways, corrections are optional.
- ATC Reporting: When applying a cold temperature altitude correction on any segment except the final segment, you must advise ATC of the corrected altitude.
- Correction Methods: FAA recommends either the All Segments Method or the Individual Segments Method.
Understanding CTAs is critical for IFR operations in winter — flying the published altitude without correction in extreme cold could put you below obstacle clearance.
Five FAA-written-style questions. Instant explanations, every answer cites its source — no account needed.
You are flying VFR in Class E airspace at 8,500 feet MSL during the day. What are your minimum visibility and cloud clearance requirements?