Definition
An aircraft approach category covering aircraft with a reference landing speed (VREF) of 166 knots or more. Approach categories group aircraft by speed so that instrument approach minimums (visibility and circling minima) can be matched to how fast the aircraft actually flies the approach.
Plain English
A grouping label for the fastest aircraft on instrument approaches — those that cross the runway threshold at 166 knots or faster. Because they fly the approach quickly, they need different (usually higher) weather minimums than slower aircraft.
Context Anchor
Seen on instrument approach charts and in approach minimums, where aircraft category affects which landing minimums and protected areas apply.
Derivation
The categories are simply lettered A through E in order of increasing speed. Category E is the highest speed bracket — primarily military and certain high-performance jets.
Why Pilots Care
It sets the higher approach speeds, visibility, and ceiling minimums required for safe operations with fast aircraft.
Intuition Check
Category E does not mean a special aircraft type or certification class by itself. In this context, it means an approach-speed group: 166 knots or faster.
Example Sentence 1
The crew checked the Category E minimums on the approach plate before briefing the ILS.
Example Sentence 2
Category E minimums on the ILS require greater visibility than Category C minimums for the same runway.