Traffic Pattern (Circuit)

Traffic pattern or circuit – how to fly standard VFR approach and departure? And how to avoid common mistakes?

Krąg1

Short intro. I was sure that writing about patterns is not necessary. There are lots of pattern descriptions and tutorials on the web. But I was surprised to see how many youtube videos show people who fly patterns completely wrong. The same happens on Vatsim. Virtual pilots make the same mistakes as the real ones but they are never corrected. For this text I compiled the most important information and described common mistakes so that you can follow the good lead and avoid running into trouble.

Traffic pattern (Circuit)

Traffic pattern and circuit are the same thing. The first name is more popular, the second is used in Britain and Commonwealth countries.

When flying the pattern you need to fly 5 legs that create a rectangular shape.

  • departure;
  • crosswind leg;
  • downwind leg;
  • base leg;
  • final.

How to fly traffic pattern? (simplified description for those who have no time to read everything)

  1. Take off.
  2. Climb at Vy – best rate of climb speed.
  3. Retract gear and flaps (if necessary).
  4. Turn crosswind (at 500ft Above Ground Level, no sooner than over the far end of the runway).
  5. Climb at Vy to 1000 ft AGL.
  6. Turn downwind (about half mile from runway).
  7. Prepare for landing. Extend gear (if necessary).
  8. Turn base.
  9. Start descent. Extend flaps (if necessary). Fly at 1,4* Vso (Vso – stall speed in landing configuration).
  10. Turn final at 500 ft. Extend more flaps (if necessary).
  11. Land.

And look around you. You are flying visually.

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Traffic pattern – detailed explanation

Departure – climb

After take-off accelerate to best rate of climb speed. In some situations (noise abatement or obstacles) you may choose best angle of climb speed (Vx). You will find both (Vx and Vy) in aircraft manual.

1st turn (crosswind turn) – no sooner than above the far end of runway

This is often omitted in shorted tutorials. You need to fly the whole length of runway before making the first turn. Cessna 172 taking off from a long runway may climb to the pattern altitude before turning crosswind.

It is good to practice traffic patterns over various airports that have long and short runways.

Crosswind turn – level or climbing?

The real world guides and handbooks mention both options. You may find some that suggest doing level turn and some that suggest climbing turn. Both are ok – climbing turn gives you slightly better altitude in case of an engine failure and level turn should give you more speed. Altitude can be exchanged for speed – so this is almost the same situation. I personally prefer climbing turns – you may find them easier because your speed (and therefore your trim) does not change.

It is a good idea to make the first turn with slightly lower bank than the second and third turns (around 20 degrees in the first, 20-30 in the 2nd and 3rd). Keep in mind that your stall speed increases with your bank angle.

Crosswind turn – proper altitude – 300, 500 or 700 ft?

Some handbooks say 300 ft is ok. Some (AOPA) say 300 ft below the pattern altitude (this means 700 ft  for a standard pattern).

It is the pilot who decides when to turn. Consider this – would you prefer to have more altitude (and more gliding distance) making recovery in case of the engine failure?

I mostly use 500 ft when flying in FSX. Sometimes (due to terrain or other obstacles or impossible terrain in front of me) I choose 700 ft.

Downwind turn – when to turn?

AOPA and FAA handbooks suggest a half mile distance between the runway and the downwind leg in a standard pattern. This is a good distance and you will need to learn to judge it from the air.

This is not a fixed distance. Faster aircraft usually fly larger patterns and slower aircraft fly smaller patterns.

If there is a traffic in pattern – it is best to follow it.

Base turn – when to turn?

At least once there is an agreement between handbooks and guides that I read. You should make the third turn when the angle between you and your touchdown zone is 45 degrees (back). AOPA in their guide gives 1/2 – 3/4 mile after passing the point abeam to the runway threshold. Thet is roughly the same position that the previously mentioned angle will give you.

Illustration: FAA

Illustration: FAA

Base to final turn

You should start your turn in a correct place to line up with the runway. It may take some practice. In case of a crosswind – make sure that the wind does not blow you too far on either side of the centerline.

There is no set altitude for the final turn but do not get too low here. You should be in gliding distance from the runway in case the engine fails.

Flaps

In a general aviation aircraft – small flaps on take-off and in base leg and full flaps on final.

It is not uncommon to use different flap settings. For example Cessna 172 can take-off with no flaps. It can land using the full range of flaps (from no flaps to full flaps). Decide what is necessary – it is good to use more flaps when landing on grass or rough surface. You will need flaps for shorter landings. You may land with small (or no) flaps on a long, paved runway.

Always refer to the aircraft POH to know what flap settings are best.

When using flaps on base leg and final – do not “fight” them with your throttle. If keeping speed and altitude requires high thrust – retract flaps.

Gear

Lower your landing gear in downwind and make sure that it is down and locked (“three green” or a similar indication).

If you need to slow down and/or extend flaps before you lower your gear – do that in downwind leg.

Speed

I have seen several videos showing FSX patterns flown at 140, 160 or 180 knots. In a normal GA plane – it is awfully fast.

The speed will vary between different aircraft. Some sleek and powerful planes will fly patterns at 120 knots. Cessna 152 – at 80-90.

90-110 is a good range for most GA planes.

Pattern altitude

1000 feet AGL – standard pattern altitude for aircraft.

1500 ft AGL – pattern altitude for fast planes (usually turboprops, jets, etc.).

Use of PAPI lights

PAPI lights show the correct (usually 3 degree) glide path for IFR aircraft. You should not fly PAPI when flying patterns in a single engine piston plane – they show a low approach.

Interesting view of Pattern Flying

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Common mistakes and their consequences

Too high on approach

Late descent or early third turn may result in a steep approach. If landing requires vertical speed in range between 800-1000ft/min and the aircraft accelerates in descent – it is wise to abort the landing and go around.

Low approach

For some reason – this is the favorite approach of Vatsim/Youtube FSX pilots who fly long (2-3 mile) finals starting at 400ft. Usually with full flaps and roaring engine. If you already have seen the video I embedded above – you know where the problem is.

Huge traffic pattern

Another thing that I often see on Vatsim and in FSX videos. People tend to fly enormous traffic patterns. I have the easy solution to “unlearn” this habit – just cut the throttle at any point of the pattern and try to land on the runway. If you can – the pattern size was good.

Speed

It is just too fast when you fly 140 knots in a Comanche or 160 kn in Lancair in a traffic pattern. You will find it difficult to do everything you need to when flying so fast nad it will be impossible to slow down to a proper landing speed.

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Soon in this series

  • Pattern exit and entry
  • Right of way and overtaking
  • Communication
  • Videos
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Traffic Pattern (Circuit)
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Traffic pattern or circuit - how to fly the standard VFR approach and departure? And how to avoid common mistakes?
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