14 CFR 77.3 - Definitions.
For the purpose of this part:
Non-precision instrument runway means a runway having an existing instrument approach procedure utilizing air navigation facilities with only horizontal guidance, or area type navigation equipment, for which a straight-in non-precision instrument approach procedure has been approved, or planned, and for which no precision approach facilities are planned, or indicated on an FAA planning document or military service military airport planning document.
Planned or proposed airport is an airport that is the subject of at least one of the following documents received by the FAA:
(2) Airport Improvement Program requests for aid.
(4) Airport layout plans.
(6) DOD proposals on joint-use (civil-military) airports.
(7) Completed airport site selection feasibility study.
Precision instrument runway means a runway having an existing instrument approach procedure utilizing an Instrument Landing System (ILS), or a Precision Approach Radar (PAR). It also means a runway for which a precision approach system is planned and is so indicated by an FAA-approved airport layout plan; a military service approved military airport layout plan; any other FAA planning document, or military service military airport planning document.
Seaplane base is considered to be an airport only if its sea lanes are outlined by visual markers.
Visual runway means a runway intended solely for the operation of aircraft using visual approach procedures, with no straight-in instrument approach procedure and no instrument designation indicated on an FAA-approved airport layout plan, a military service approved military airport layout plan, or by any planning document submitted to the FAA by competent authority.