In United States aviation VFR-on-top is defined as air traffic control authorization for an aircraft operating under
instrument flight rules
In aviation, instrument flight rules (IFR) is one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other is visual flight rules (VFR).
The U.S. Federal Aviation Administration's (FAA) ''Instrument Fly ...
(IFR) to do so in
visual meteorological conditions
In aviation, visual meteorological conditions (VMC) is an aviation flight category in which visual flight rules (VFR) flight is permitted—that is, conditions in which pilots have sufficient visibility to fly the aircraft maintaining visual sep ...
(VMC) at any appropriate visual flight rules (VFR) altitude.
A pilot receiving this authorization must comply with the VFR visibility, distance from cloud criteria, and the minimum IFR altitudes. The use of this term does not relieve controllers of their responsibility to separate aircraft in
Class B and Class C airspace or
TRSAs.
See also
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VFR over-the-top
VFR over-the-top (OTT) refers to flying over top of clouds in visual flight, rather than with reference to instruments. This is usually done for brief amount of time to avoid weather or turbulence.
Regulations
Each nation has specific and often d ...
References
91.179(A) §91.179 IFR cruising altitude or flight level.– US Government Publishing Office
Air traffic control
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