Definition
A specific prohibited area of airspace overlying the Camp David presidential retreat in Maryland, within which flight by aircraft is not permitted. Like all prohibited areas, P-40 is established for reasons of national security and welfare, and its lateral and vertical limits are published on aeronautical charts along with the times of designation.
Plain English
P-40 is a piece of airspace over Camp David where aircraft are not allowed to fly. It is one of a small number of named no-fly zones in the United States.
Context Anchor
Seen in special use airspace discussions and on aeronautical charts when planning flights in the Maryland area.
Derivation
The 'P' stands for Prohibited, and '40' is simply its identifying number in the FAA's list of prohibited areas. Each prohibited area gets a unique number so pilots and controllers can refer to it precisely.
Why Pilots Care
Entering this area without clearance risks interception by military aircraft and serious regulatory penalties.
Intuition Check
P-40 does not mean an aircraft model in this FAA context. Here, it is the label for a specific prohibited airspace area.
Example Sentence 1
Before the cross-country, the instructor pointed out P-40 on the sectional and explained why the planned route stayed well clear of it.
Example Sentence 2
Preflight review of the sectional chart highlighted P-40 as a restricted zone near the planned path.