When you think of flying, you often imagine a pilot sitting in a cockpit transfixed onto multiple instruments. In most cases this is true, but it’s not always the case. When it comes to flying there are two major rules. Your whole career as a pilot will revolve around these rules.
- VFR or Visual flight rules
- IFR or Instrument flight rules
Flying in Visual flight rules
VFR is as simple as it sounds. Flying with the help of visual references. Flying with the help of what you see outside while flying while in coordination with instruments. The pilot will still use the instruments to relay certain information, such as altitude and airspeed. But, what they see outside the window is used to determine the aircraft’s position and attitude. My instructor used to say, flying VFR is to “See and be seen”. Now to see and be seen while flying, what do you need?? You need a clear day. There are a few parameters specified by dgca to be flying within visual flight rules.
The table above is taken from AIP India. Most of the parameters are mentioned in this table. But in simple words, in most cases you need 5km visibility and a distance of 1500 m horizontal and 300 m vertically from any cloud to be flying in VFR. It basically indicates that you need a clear day to be in VFR conditions. For the purpose of dgca exams it’s better if you memorise the above table. There are a few other conditions that will not let you fly in VFR. Let’s have a look.
- VFR flights shall not be operated between 20 minutes after sunset to 20 minutes before sunrise, except when exempted by air traffic control for local flights* and such training flights of flying club aircraft as may be cleared by air traffic control.
- VFR flights shall not be operated above flight level 150.
- VFR flights shall not be operated at transonic and supersonic speeds.
- VFR flights shall not be operated more than 100NM seaward from the shoreline within controlled airspace.
When it comes to VFR these are the basics. For more detailed info I’m linking the eAIP for your reference.
Instrument flight rules
My instructor had a very easy way of explaining about IFR. He used to say, when you are not in VFR you are in IFR. Basically if you do not have good visibility conditions or if it’s cloudy, you cannot see and be seen well right, so how will you fly visually??. For this purpose there is IFR.
Instrument flight rules, are when the aircraft is maneuvered and navigated with sole reference to the aircraft instruments. There is no requirement to be visual with the ground or even with the horizon.
The pilot will be able to find out altitude, speed, attitude rate of climb, heading, and even their position over the ground using the basic instruments in combination.
Flying IFR takes a lot of practice and relies on the pilot having a good ‘scan’ where they look briefly at each instrument in a sequence to build a good overall mental picture of what is happening to the aircraft.
I have tried to explain IFR and VFR in a simple manner, in the best of my abilities. I would like to add that many pilots prefer IFR over VFR because they can fly regardless of the weather conditions. They aren’t constrained by the VFR minimums you saw above. But overall both have its merits. I hope you enjoyed the read. Happy landings.