Definition
Rules applicable to flights within an Air Defense Identification Zone (ADIZ) conducted under visual flight rules. Pilots operating DVFR must file a DVFR flight plan and comply with security control procedures before crossing or operating within the ADIZ.
Plain English
A special set of rules for flying by visual reference inside a security zone around U.S. borders. Even though you're flying VFR, you must file a flight plan and follow extra identification procedures so air defense knows who you are.
Context Anchor
You may see this term when planning a VFR flight near a U.S. coastline, border, or other area where an Air Defense Identification Zone applies.
Derivation
Defense' refers to national air defense identification requirements. 'Visual Flight Rules' means flying with reference to what you can see outside, rather than by instruments alone. Together: VFR flying that also satisfies air defense identification needs.
Why Pilots Care
Failure to file and follow these rules can result in interception by military aircraft or delays in crossing sensitive airspace.
Intuition Check
Do not read “Defense” as combat or military maneuvering. Here it means extra identification rules for a civilian VFR flight in airspace monitored for national security.
Example Sentence 1
Before departing for the Bahamas, the pilot filed a DVFR flight plan to comply with ADIZ requirements when re-entering U.S. airspace.
Example Sentence 2
Under Defense Visual Flight Rules the aircraft maintained radio contact and reported its position at each checkpoint.