Definition
An additive height value, in feet, that pilots add to published instrument approach altitudes when the reported airport temperature is at or below a designated cold-temperature threshold, in order to compensate for the fact that a pressure altimeter reads higher than the aircraft's true altitude in cold air. The correction is applied at one or more approach segments (intermediate, final, missed approach) on charted Cold Temperature Restricted Airports, using values derived from the ICAO cold temperature correction table or equivalent FAA guidance.
Plain English
When the air is very cold, your altimeter shows you higher than you actually are. To stay safely above terrain and obstacles, you add a set number of feet to your approach altitudes. That added number is the cold temperature altitude correction.
Context Anchor
Seen on instrument approach procedures, FAA cold-temperature airport procedures, and altitude planning for approaches in very cold conditions.
Derivation
Correction comes from a word meaning “to make right.” Here it does not mean fixing the altimeter; it means making the altitude you fly high enough to match the safety margin the procedure was designed to provide.
Why Pilots Care
Without the correction a pilot may descend below published minimum altitudes and strike terrain or obstacles that the procedure was designed to clear.
Analogy
It is like adding a safety allowance to a measuring stick when you know the stick reads too high in cold weather. You are not changing the ground; you are adjusting what you fly so the real clearance stays safe.
Grounding Statement
Cold air makes pressure levels sit closer together, so an altimeter can indicate a safe altitude while the aircraft is actually lower than expected.
Intuition Check
Cold temperature altitude correction does not mean changing the altimeter setting or correcting the weather report. It means adding altitude to what you fly so the aircraft’s true height remains safe in cold air.
Example Sentence 1
With the airport reporting -20°C, the crew applied a cold temperature altitude correction of 200 feet to the final approach segment before briefing the approach.
Example Sentence 2
Because the airport temperature was minus 30 degrees, the crew applied the cold temperature altitude correction to every altitude on the ILS.