Wind Pushes and Pulls

We commonly think about how the wind pushes the airplane, but did you know that the wind pulls as well?

Cruising with a tailwind pushes us forward while headwind pushes us back. If we are flying with a crab angle we can look at the ground and get the feeling that we are flying sideways. In these cases, the wind is pushing us from whichever direction it is coming from.

Sometimes the wind pulls us

Continue reading “Wind Pushes and Pulls”

Traffic Patterns Part 6: Wind

Wind can have a large effect on the traffic pattern, especially when it comes to the base and final leg.

You should familiarize yourself with the current wind at the airport before takeoff and when preparing to enter the pattern. Remember that the wind report you get from an automated station is on the surface and may not be as strong as the wind at pattern altitude.

When flying each leg around the pattern think about whether the wind is coming from your left or right and crab towards it to fly a straight track. When preparing to land look at the crosswind and what it will do to your base leg.

If you expect to have a tailwind on base you will need to turn final sooner in order to not overshoot the runway. Conversely, if you experience a headwind on base you can expect to have more time before you need to turn final. More time also means more time to descend, so adjust you glidepath and consider adding some power.

On final, if you face a strong headwind component you will again have more time to descend and may need more power to make it to the runway.

Plan in advance so you know what to expect in each leg of the pattern.


Traffic Patterns Part 5: Directions

Left or Right

Traffic patterns at a non-towered airport are usually left-handed patterns, meaning that all turns are made to the left. There are exceptions, and you can find these details on a sectional chart. See the sectional chart for Brandywine airport, below. There is a lot of airport info here, including “RP 9” which means that a right pattern is to be used for runway 9.

Why a right pattern?

The reason for the right pattern doesn’t really matter, but it can be interesting. In this case, there may be two reasons for this. The first is that the airport has a reservoir to the south. If all planes use a right pattern for runway 9 and a left pattern for runway 27 then all of the traffic will be over the reservoir and reduce the noise footprint over the QVC studio located north of the airport.

Second, Brandywine is home the American helicopter museum on the north side of the field. If the airplane traffic is kept to the south then helicopters can operate more freely on the north side without conflicts. Go visit the museum if you are ever in southeastern Pennsylvania, its great!

Helicopter Pattern

In airplanes, we generally fly left patterns. This is because the pilot sits on the left side so the left pattern gives him an excellent view of the airport and other planes operating there. Helicopter pilots sit on the right side so they fly right patterns. This helps to separate helicopter and airplane traffic as well.

So stick to the left pattern unless otherwise published. Don’t take a shortcut just to get to the runway faster. The correct way to enter the pattern is much safer.


Switching Runways

The wind changes and you must adapt to it. Sometimes this means that the full pattern will need to switch to the other side of the airport.

The simplest runway switches are done at airports with a standard left pattern to both runways. To switch simply use the downwind leg you are flying as an upwind leg. Then stay at pattern altitude and turn crosswind instead of base. Your next turn will be another left onto downwind for the new runway.

If you are switching from a left pattern to a right pattern on the opposing runway (like you would at Brandywine) simply depart the pattern and maneuver to enter the 45 for the new runway. Be careful about any planes that may still be in the old traffic pattern as they will be flying head-on towards you. Do not enter the new pattern unless everyone is flying the same way.

If you are at an airport with multiple crossing runways and you decide to switch to another runway, again, you should announce your intentions so hopefully the other planes will follow suit. Then, depending on the specific layout of the field you will fly your pattern at altitude until one of the legs of the old pattern puts you in a good position to get on downwind for the new pattern. When in doubt depart the pattern and reenter to try again.

Think like a Glider Pilot

Recently I was flying a Piper Arrow at 2500 feet in turbulent air. I was carefully maintaining my altitude with pitch and trim changes. It was a bumpy ride but it was nice watching the puffy cumulus clouds pass by overhead.

Then I began to notice my indicated airspeed was changing despite my unchanged engine settings. First, my speed would be up about 10-15 knots for a minute or so, then it would drop back down for another minute. The next minute it was back up.

Why was this happening?

I thought about it for a few minutes. The engine RPM and manifold pressure were constant, and my altitude was constant.

This could only be caused by updrafts and downdrafts! Yes, the same turbulent air that was creating those clouds was pushing the plane up every time I passed under one.

You can imagine my plane flying in that mass of rising air, and me correcting almost subconsciously to maintain altitude. As the air mass rises, I need to pitch down to stay at the same altitude. This is as good as descending as far as airspeed is concerned.

These updrafts are what glider pilots use to stay airborne and even climb without an engine. A single-engine plane is far too heavy to stay aloft on the updrafts alone, but they do offer us free airspeed which can save on rental or fuel costs.

But how do we take advantage of them?

First, there is terrain: When you have any kind of terrain plan to stay on the upwind side as much as possible. As the wind reaches rising terrain it will rise to go over it and this rising air provides a great updraft that you might be able to take advantage of by altering your course just a little.

Second is cloud streets: Puffy cumulus clouds are formed in rising air so alter course slightly if it will put you under some cumulus clouds. It may be bumpy but if you are between clouds the air will generally be descending to replace the rising air under the cloud. Glider pilots look for cloud streets, which are long rows of clouds that can provide an updraft over a very long distance.

Just think like a glider pilot and consider how the air around you is moving. Tailwinds get all the attention when looking for bonus performance from the environment, but a nice updraft can help any aircraft to go just a little bit faster for the same power.