Tips for Fun Fall Flying and What to Be Aware of With Falling Temps
Ask most pilots when they have their best flights and a lot of them will say in the fall. The summer haze lifts, the bumpy air smooths out and the air turns cool and dense. For a good part of the country it is the sweet spot of the flying calendar.
As cooler air rolls in, fall means different things depending on where you fly. If you’re in the northern half of the country, these next few weeks are when you start thinking about winter storage. If you’re based along the Gulf Coast, in the Southwest or anywhere the weather stays friendly, fall is the kickoff for your prime season. Here’s what you can make the most of, and what to keep an eye out for, as you fly into fall.
Why Fall Earns Its Reputation
There is real substance behind the “best flying of the year” claim, and most of it is physics rather than sentiment. Here are four reasons why:
- The air is smoother. The bumpy air in the summer comes from thermals, which are columns of warm air rising off ground the sun has heated. As the sun sits lower through fall, the ground heats less and throws off far fewer thermals, so the ride gets noticeably smoother and early mornings turn glassy.
- Your plane performs better. Cooler air is denser air, and denser air is free performance. As density altitude drops, you get shorter takeoff rolls, stronger climb rates and better prop efficiency. The same 172 or Archer that felt sluggish clawing out of a hot July afternoon will feel like a different airplane on a crisp October morning.
- Visibility opens up. Summer heat traps haze and humidity down low. Fall cold fronts scrub the air clean and dry, which is why the season is known for those CAVU days.
- Fewer thunderstorms. The convective season winds down, so there are fewer afternoon buildups to route around and more stable, predictable windows when planning your flight.
Enjoy it, but do not get complacent. Cooler mornings and warmer afternoons mean the temps can swing widely in a single day, so keep running your performance calculations rather than relying on last month’s numbers. Here are a few things to prepare for as the season changes.
Carb ice: watch for it as temps cool
If you fly a carbureted engine, carburetor ice is the fall hazard to stay most vigilant about. A number of GA piston aircraft have carbureted engines, including many of the most common Cessna and Piper models flying today.
Carb ice doesn’t need freezing weather. It forms when moist air passing through the carburetor cools sharply, and the cool humid conditions common on fall mornings and evenings are worth being aware of this time of year. The danger window is widest at low power settings, which is exactly when you’re least likely to notice a gradual drop in RPM or manifold pressure.
A few habits worth reinforcing this time of year:
- Use carb heat on descent and any time you are at reduced power, per your POH.
- Treat an unexplained RPM or manifold pressure drop as suspected carb ice until proven otherwise.
- Do a full carb heat check during runup and pay attention to it.
If you fly a fuel-injected engine, carb ice is off the table. You’re not entirely off the hook though, so stay aware of induction and impact icing in visible moisture. If you’re ever unsure which type you have, your POH or your mechanic can tell you in a moment.
Shorter days can sneak up on you
A big change of fall flying is reduced daylight. Sunset marches earlier every week, and a flight that launched in full daylight in August can easily land after dark in October.
Two things to stay ahead of:
- Night currency. To carry passengers at night you need three takeoffs and landings to a full stop after dark within the preceding 90 days. If your summer was all daytime hops, that currency may have quietly lapsed. Knock it out on a clear evening before you need it.
- The aircraft side. Check that your position lights, landing light and any interior lighting actually work before your first night flight of the season. And toss a good flashlight with fresh batteries in the cockpit for backup.
Earlier dusk also means more wildlife on and near rural runways right when visibility is dropping, so keep your eyes moving on approach to unlit fields.
Fall weather has its own personality
The season brings a handful of conditions worth planning around:
- Radiation fog. Clear calm nights and cooling temperatures are a recipe for morning fog, especially near rivers and low ground. Watch the temperature and dewpoint spread. When it closes to within a few degrees, expect fog to be possible and give it time to burn off.
- First frost. Cooler mornings can leave frost on wings and tail. Any frost has to come off before flight, no exceptions, so build a few extra minutes into your morning preflight to clear it.
- Frontal passages. Fall cold fronts can bring gusty shifting winds and quick changes in ceiling and visibility. Check the whole picture, not just departure weather, and respect crosswind limits that are easy to forget after a calm summer.
Check for uninvited guests
As the nights cool, mice, birds and insects start looking for warm sheltered spots, and a parked airplane is exactly that. Fall is peak season to find nests in cowlings, control surfaces, wheel pants and pitot tubes, along with rodents that chew wiring and insulation.
Thoroughly inspect for nests and blockages as part of every preflight this time of year, and pull pitot and other covers to confirm they are clear. A mud dauber nest in a pitot tube or a chewed wire can turn into a real problem in the air.
If you're putting the plane away for winter
For our northern owners, fall is storage prep time. A little effort now protects the airplane and makes spring return to service far easier. The essentials:
- Change the oil before it sits. Used oil holds combustion acids and moisture that corrode internal engine parts during a long rest. Adding fresh oil is one of the cheapest things you can do to protect the engine over the winter.
- Top off the tanks. Full tanks leave less room for air, which means less condensation and water in your fuel come spring.
- Protect the engine from corrosion while it sits. For shorter layoffs, flying it regularly is the best medicine. For longer sits, look into cylinder preservation and desiccant plugs per your engine maker’s guidance.
- Maintain the battery. A tender will keep your battery healthy with a trickle charge, or you can pull it and store it somewhere warm.
- Seal up to keep critters out. Cover on every opening, and seal your plane and the hangar during the cold winter months.
Whatever you have planned for the season, fall is always a fun time for pilots. Enjoy the smooth air and the strong climbs, respect the shorter days and the changing weather, and set your plane up for an easy return when the warm air comes back.