IFR Conditions
IFR conditions are meteorological conditions in which visual flight rules cannot be maintained — that is, conditions where the ceiling or visibility (or both) are below the applicable VFR minima. Flight in IFR conditions without an instrument rating and an IFR clearance is illegal and extremely dangerous.
IFR Conditions and IMC
IFR conditions and IMC (instrument meteorological conditions) are related but slightly different concepts. IMC describes any condition where the weather is below VFR minima. IFR conditions specifically describes the regulatory threshold at which VFR flight is no longer permitted. In practice, the terms are often used interchangeably.
Inadvertent IMC
Inadvertent flight into IMC by a VFR-only pilot is one of the most lethal scenarios in general aviation. A VFR pilot who enters IMC has on average approximately 180 seconds before losing control and entering a spiral dive (the “graveyard spiral”). The correct immediate action is a 180° turn to return to VMC — executed promptly and accurately.
On the TC Written Exam
Know the VFR weather minima for all airspace classes and how they relate to IFR conditions. Know the immediate response to inadvertent IMC.