Definition
The pressure altitude at which an aircraft is flown during the cruise portion of a flight. Pressure altitude is the height above the standard datum plane (29.92 inches Hg), so cruising pressure altitude is the altitude shown on the altimeter when it is set to 29.92, while the aircraft is in level cruise.
Plain English
The cruise altitude expressed using the standard altimeter setting of 29.92, rather than the local altimeter setting. It is the number you would see on the altimeter at cruise if you set it to the standard pressure reference.
Context Anchor
Seen during IFR preflight planning when selecting a cruise altitude and estimating aircraft performance for the en route part of the flight.
Derivation
‘Cruise’ comes from the Dutch ‘kruisen,’ meaning to cross or sail back and forth — the steady middle portion of a journey. ‘Pressure altitude’ is altitude measured against a fixed pressure reference (29.92 in Hg) rather than the actual local pressure. Combined, the term means the cruise-phase altitude expressed against that fixed reference.
Why Pilots Care
It provides a consistent reference for performance calculations, fuel planning, and maintaining proper vertical separation in the IFR system.
Intuition Check
Do not read “cruising pressure altitude” as cabin pressure or as a relaxed style of flying. Here, “cruising” means the level en route phase, and “pressure altitude” means altitude measured from the standard pressure reference.
Example Sentence 1
She filed a cruising pressure altitude of 8,000 feet and used the performance chart at that level to calculate fuel burn.
Example Sentence 2
Performance charts require the cruising pressure altitude to determine true airspeed and fuel consumption.