Definition
A set of flight rules applied to VFR flights operating into, within, or out of an Air Defense Identification Zone (ADIZ). A DVFR flight plan must be filed before the flight, and the aircraft must maintain a two-way radio capability and a working transponder while operating in the ADIZ. The rules exist so that civilian VFR traffic can be identified by air defense authorities and not mistaken for an unknown aircraft.
Plain English
DVFR is the version of VFR flying you must use when crossing or operating in an Air Defense Identification Zone. You file a special flight plan, stay in radio contact, and keep your transponder on so the military and ATC can tell you apart from an unknown aircraft.
Context Anchor
Seen on flight plan forms and in planning for flights near U.S. borders, coastlines, or other air-defense identification areas.
Derivation
Defense refers to national air defense -- the system that watches for unidentified aircraft entering U.S. airspace. VFR means Visual Flight Rules. Putting Defense in front signals that ordinary VFR rules are not enough here: extra identification requirements apply because the flight is entering airspace where unknown traffic is treated as a security concern.
Why Pilots Care
Ensures national security compliance and prevents military interception during VFR flights in sensitive airspace.
Intuition Check
DVFR is not IFR, and it is not a special way of flying the airplane. It is a VFR flight plan with extra identification requirements for air-defense purposes.
Example Sentence 1
Before departing for the Bahamas, the pilot filed a DVFR flight plan to satisfy the ADIZ requirements along the Florida coast.
Example Sentence 2
Under DVFR the aircraft must remain in two-way radio contact with ATC while in the zone.