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IFR to VFR on Top

Introduction:

  • You can fly in great visibility above a layer of clouds, provided you have a safe way to get up and far more importantly, a safe way to get back down
  • Along the Pacific Coast, particularly in winter, there can be dense early morning fog with visibility less than 1/2 mile on the runway, but the fog layer tops out in bright sun only a thousand feet higher
  • Even the low coastal hills are above it all in clear air, as are all the inland airports
  • Closer to home, most, if not all, airports located in the bottom of a valley can experience the same thing, particularly after a nighttime temperature inversion
  • Instead of flying the whole flight on an IFR flight plan along assigned routes, you can file a flight plan for IFR to VFR-on-top
  • Instead of filing IFR, you file you file your flight plan IFR to VFR-on-top
  • You still go through all the complete instrument procedures of getting a clearance before you take off, reading it back, flying an assigned route or assigned departure procedure, squawking an assigned code on your transponder, and contacting a controller
  • You depart on an instrument flight just like any other instrument flight
    • The difference is that the instructions in your instrument clearance read something like "...departure frequency [Frequency], climb as filed to VFR-on-top, if not VFR by [Altitude], maintain [Altitude] and advise..."
  • Once you break out on top of the clouds, you can cancel IFR and fly VFR
  • Remember again that IFR flight is an entirely controlled procedure, while VFR flight outside the boundaries of an airport is uncontrolled
  • The same controller who was just telling you what to do is now only advising you
  • You cannot casually lapse back and forth from one to the other
  • The controller is going to remind you of this after you cancel IFR by instructing you to "Maintain VFR"
  • In fact, while the Instrument portion of the flight is handled by an air route traffic control center (called XYZ Center on the radio), the visual portion of the flight plan is on file with a Flight Service Station located somewhere else on a different frequency, (called ABC Radio)
  • In effect, you have two flight plans on file with two different groups of people, each of which needs to be activated and closed
    • The Instrument flight plan opens automatically when you are cleared for takeoff
    • It closes when you tell a controller "cancel IFR"
    • The visual portion of the flight plan does not automatically activate
    • It activates when you call Flight Service and activate it, and closes when you call and close it
    • After you cancel IFR, you need to call a Flight Service radio - whose frequency is typically found on your sectional chart - and activate your VFR flight plan
    • Then you need to either close it by phone or radio when you land
    • If for some reason you don't break out of the clouds as expected, a second flight plan is used if you need an assigned routing to continue
  • Also, if you don't arrive at your destination, someone will come looking for you and they will know where to look

IFR Clearance for VFR-on-top:

  • A pilot on an IFR flight plan operating in VFR weather conditions, may request VFR−on−top in lieu of an assigned altitude
    • This permits a pilot to select an altitude or flight level of their choice (subject to any ATC restrictions)
  • Pilots desiring to climb through a cloud, haze, smoke, or other meteorological formation and then either cancel their IFR flight plan or operate VFR-on-top may request a climb to VFR-on-top
    • The ATC authorization must contain either a top report or a statement that no top report is available, and a request to report reaching VFR-on-top
    • Additionally, the ATC authorization may contain a clearance limit, routing and an alternative clearance if VFR−on−top is not reached by a specified altitude
  • A pilot on an IFR flight plan, operating in VFR conditions, may request to climb/descend in VFR conditions
  • ATC may not authorize VFR−on−top/VFR conditions operations unless the pilot requests the VFR operation or a clearance to operate in VFR conditions will result in noise abatement benefits where part of the IFR departure route does not conform to an FAA approved noise abatement route or altitude
  • When operating in VFR conditions with an ATC authorization to “maintain VFR−on−top/maintain VFR conditions” pilots on IFR flight plans must:
    • Fly at the appropriate VFR altitude as prescribed in 14 CFR Section 91.159
    • Comply with the VFR visibility and distance from cloud criteria in 14 CFR Section 91.155 (Basic VFR Weather Minimums)
    • Comply with instrument flight rules that are applicable to this flight; i.e., minimum IFR altitudes, position reporting, radio communications, course to be flown, adherence to ATC clearance, etc.
    • NOTE−Pilots should advise ATC prior to any altitude change to ensure the exchange of accurate traffic information
  • ATC authorization to "maintain VFR−on−top" is not intended to restrict pilots so that they must operate only above an obscuring meteorological formation (layer)
    • Instead, it permits operation above, below, between layers, or in areas where there is no meteorological obscuration
    • It is imperative, however, that pilots understand that clearance to operate "VFR−on−top/VFR conditions" does not imply cancellation of the IFR flight plan
  • Pilots operating VFR−on−top/VFR conditions may receive traffic information from ATC on other pertinent IFR or VFR aircraft
  • However, aircraft operating in Class B airspace/TRSAs must be separated as required by FAA Order JO 7110.65, Air Traffic Control
    • NOTE−When operating in VFR weather conditions, it is the pilot’s responsibility to be vigilant so as to see−and−avoid other aircraft
  • ATC will not authorize VFR or VFR−on−top operations in Class A airspace

References:

  • None