Definition
R-4401 is the alphanumeric identifier for a specific Restricted Area of airspace within the United States. The 'R' indicates the airspace is restricted, and the number that follows uniquely identifies that particular area on aeronautical charts and in regulatory publications. Restricted Areas contain activity hazardous to nonparticipating aircraft, such as artillery firing, aerial gunnery, or guided missiles, and entry without permission from the controlling agency is prohibited when the area is active.
Plain English
R-4401 is the official name of one specific patch of restricted airspace. The 'R' tells you it's restricted, and the number tells you which one. Pilots can't fly through it when it's active without permission.
Context Anchor
Seen on sectional charts, other aeronautical charts, and during preflight route planning near special use airspace.
Derivation
The 'R' prefix is a standard FAA designator for Restricted Areas. The four-digit number is simply an identifier assigned by the FAA -- it has no hidden meaning, much like a road number. Once you know the 'R' means restricted, the rest is just an address.
Why Pilots Care
Entering without clearance risks collision with hazards and regulatory violations that may result in interception or enforcement action.
Intuition Check
Do not read R-4401 as a radio frequency, route number, or runway reference. In this context, it is the label for a restricted area on an aviation chart.
Example Sentence 1
The instructor pointed out R-4401 on the sectional and explained that the route would need to be adjusted if the area was active during the flight.
Example Sentence 2
Flight service advised that R-4401 would remain cold for the planned departure time.