- Instrument Flight Rules -

Most commercial aviation flights are flown under Instrument Flight Rules (IFR). If the conditons are below the minimums for VFR, then they are called Instrument Meteorological Conditions (IMC) under which IFR is flown.

Flight Minimums

Under IMC flights take place through clouds and hence when visibilities are zero. However, when flying IFR, you must ensure that the flight takes place at or above:

- 1000ft above the highest obstacle within 5 nm and;
- the minimum flight level stated on navigation maps or SIDS/STARS

Aircraft Separation

ATC will provide adequate separations for flights following IFR from all other traffic in controlled airspace (A - E).

Flight Plans

For all flights under IFR, a flight plan must be filed. These should start with the last waypoint/navaid of the SID and end with the first waypoint/navaid of the STAR, although departure vectors may be provided by ATC.

IFR or VFR ?

It is entirely up to the Pilot that, if conditions allow, to fly VFR instead of IFR. If, say, on departure, IMC were present, then an IFR departure would be reqiured. Upon climbing above the clouds and VMC experienced, then, upon cancelling the flight plan with ATC, VFR flight could be undertaken OR, the flight could be continued under IFR. If you cancel the flightplan and then meet IMC again you would be required to re-file your flight plan and declare to ATC that you would be 'going' IFR. Simple!

The above is only really applicable to flying non commercial flights. Flights undertaken for UKD should be carried out under IFR at all times.

Aircraft Requirements

Aircraft to be flown under IFR must have an active radio and transponder.