Definition
A flight that began under Visual Flight Rules and subsequently entered Instrument Meteorological Conditions, meaning weather conditions in which the pilot can no longer see well enough outside the aircraft to control it by visual reference to the ground or horizon. This situation is one of the most lethal scenarios in general aviation because the pilot is operating under rules that assume continuous outside visibility, and may not be qualified, current, or equipped to fly the aircraft solely by reference to the instruments.
Plain English
A pilot flying by looking outside accidentally flies into clouds, fog, or weather so poor that the ground and horizon disappear. They now have to fly the aircraft using only the cockpit instruments, which is dangerous if they have not been trained for it.
Context Anchor
Seen in weather decision-making, accident reports, preflight planning, and training discussions about avoiding cloud and low visibility during visual flight.
Derivation
VFR stands for Visual Flight Rules, the regulations governing flight by outside visual reference. IMC stands for Instrument Meteorological Conditions, weather below the minimums required for visual flight. The phrase describes the transition from one to the other, usually unintentional.
Why Pilots Care
This situation is a leading cause of fatal accidents because pilots often lose control of the aircraft once visual references disappear.
Analogy
It is like driving on a clear road and suddenly entering fog so thick that the road edges disappear. If you are not prepared to navigate another way, continuing straight ahead can become dangerous very quickly.
Grounding Statement
The key idea is simple: a flight planned around seeing outside has entered weather where seeing outside is no longer enough.
Intuition Check
Do not read this as a normal or planned instrument flight. Vfr Flight Into Imc usually describes an unsafe or unintended situation where visual flying has continued into weather that requires instrument flying.
Example Sentence 1
The accident report concluded that the pilot, who held only a private certificate without an instrument rating, lost control after VFR flight into IMC near the mountain pass.
Example Sentence 2
Regulations and training stress that VFR flight into IMC must be avoided by landing or diverting early.