Definition
The lowest altitude, published on an instrument approach chart, at which a pilot may fly the procedure turn maneuver used to reverse course and align with the final approach segment. It guarantees obstacle clearance throughout the protected airspace in which the procedure turn is conducted.
Plain English
The lowest altitude you are allowed to be at while flying the turn that gets you lined up for the final approach. Going below it is not safe because terrain and obstacle clearance is no longer guaranteed.
Context Anchor
Seen on instrument approach charts and in cold-temperature correction discussions, especially when deciding whether a published approach altitude must be adjusted for very cold weather.
Derivation
Minimum comes from a Latin word meaning “smallest.” In aviation, it usually means a lower limit, not a suggestion. Altitude comes from a Latin word meaning “height,” which fits its use as the airplane’s height above a chosen reference level.
Why Pilots Care
Ensures the aircraft remains above all obstacles during the turn even though the altimeter reads higher than the aircraft's true altitude in cold air.
Grounding Statement
During the turn that gets the airplane pointed inbound on an instrument approach, this altitude is the floor the pilot must stay at or above.
Intuition Check
“Minimum” does not mean the best or normal altitude to aim for. It means the lowest altitude allowed for that part of the procedure.
Example Sentence 1
Because the outside air temperature was well below freezing, the pilot added a cold temperature correction to the minimum procedure turn altitude before beginning the course reversal.
Example Sentence 2
Because the temperature was minus twenty degrees, the crew added the required correction to the minimum procedure turn altitude.