Since I’ve had my IFR rating I’ve given a lot of thought to how useful this is going to be if most of the flying I do is in a slow airplane to an airport that may not be too far away. I have a few reasons why you may want to consider it.

The benefit to flying IFR on a mostly VFR day is that you ensure you have a legal way to depart from or arrive to an airport even if there is low cloud somewhere along the way. IFR flying has some fairly low weather limits even for GA, much lower than I would be comfortable flying VFR. Typically you would use the TAF to determine the expected weather at your destination and alternate.

The minimum requirements for an IFR departure are 1/2 SM (statute miles) visibility, and the ceiling can be below landing minimums. I’ve done this in a twin engine aircraft but I don’t think I would do that in a single. The advantage here is this might help you get an early start on a morning with some fog that is taking a long time to clear, or really low cloud.

Landing limits for most IFR approaches are also pretty low. A GPS only approach might be one mile visibility and 500 foot above the airport while an ILS approach is often 1/2 SM and 200 feet with the right type of runway lights. This can be very helpful if a mild storm and low visibility moves in on your destination and you don’t want to turn around and go home.

When you file IFR there is also a requirement to file an Alternate airport in case the weather at your destination drops below landing limits. There’s no restriction on how close or far away it has to be as long as you carry enough fuel to get there plus another 45 minutes after that as an additional safety margin. The alternate airport weather minimums are a bit higher, commonly two miles visibility and 800′ above the airport (or 600′ if it has an ILS).

The actual requirements are much more detailed and have many special cases. What this does show is that filing IFR gives you a much better chance of being able to fly if the weather just isn’t working to VFR flying that day.

One important point to note about winter flying is that IFR isn’t as useful as it is in the summer. The key issue when the weather gets below 10C is that you may have icing to deal with, and most GA planes aren’t equipped for any type of icing. The temperature drops about 2C for every thousand feet increase in altitude. The freezing level will be depicted on the second page of the GFA and is helpful to determine if you will be able to stay below that in cloud.

If the temp was 5C on the ground and you climb to 3000 AGL in cloud you may be below the freezing level and will start to ice up. The only thing you can do is get out of cloud or into warmer air. IFR flight plans require obstacle clearance along the entire route so you may not get a clearance to fly lower if you can’t exit cloud into VFR.

If your airplane is equipped for IFR and you fly to or from airports with an IFR procedure there might be some value in having an instrument rating for those days when the weather just doesn’t cooperate.