Determining distance in the pattern

[hedbonker 5]

Typically I find most patterns defined as 1000' AGL and each leg having a distance of 1nm from the runway in the pattern.  How do you determine this 1nm distance when flying in the pattern?  Is it just a visual thing that you learn from experience?  Is there a trick to it?

[charliearon 3,017]

If you are flying this "pattern" in a small aircraft, like the C-172, then keep in mind that at an airspeed of 60 knots, in one minute, you have flown approx. 1 nautical mile.  Usually flying for about 35-40 seconds per leg should be in the ballpark!

[hedbonker 5]

Awesome! Thank you Charlie!

[G550flyer 1,011]

I'm a jet guy that turn the pattern at 180kts, but I think this may work for you as well. Big thing is having proper displacement from the runway. I'm so used to eye balling, but in fast movers, I like no closer than a mile. Abeam the thresh, drop the gear. I wait till the threshold is 45 degrees off my left shoulder and start my continuous turn onto final while configuring. That 45 degrees might be a little further out than you need though. Charliearon's advice is probably best if you are flying non jet types.

[Chock 17,769]

Generally speaking, as Rick says, you get a feel for when to turn by looking over your shoulder, but what also helps is to look at the angle (i.e. the view downwards toward the end of the runway as you've flown past it and are judging when to turn). You wont go too far wrong if you use somewhere in the region of a 20 degree downward angle to the runway threshold over your shoulder as you are preparing to turn.

[spearmint_flyer 579]

I normally have the GPS set to the airport or the nearest page up. That will show me my distance from the airport all times. 1NM from the airport is roughly 1NM from the runway. 

Edited January 6, 2021 by Alcides Segovia

[fppilot 4,355]

If you are downwind with a standard rate turn you take 30 seconds in the turn to base, and another 30 seconds in the turn to final.  I was trained to make two turns, not one 180° turn.  So based on your speed you calculate two turns, one from downwind to base, and the other from base to final, with a comfort level time interval in between.  We in practice used 30 second increments.  Apply that to your speed.  The flat segment from base to final can certainly be shortened based on conditions and ability.  That went hand-in-had with instrument training.

Edited January 6, 2021 by fppilot

[DavidP 1,408]

Keep it simple! Lot's of rule of thumb without the mental gymnastics.

On crosswind, look over your shoulder and when the threshold is at 45 degrees (horizontally), turn downwind (another method is look over your shoulder and when the tail crosses the runway, turn downwind.

On downwind, when the approach threshold is 45 degrees (horizontally) over your shoulder, turn base

On downwind in a high wing Cessna, the runway runs along the wing strut about 2/3 up the strut on a left circuit, half way on a right circuit.

[COBS 25]

Several years ago I created a "Synthetic ILS" instrument , it is available freeware  at Simviation and Flightsim libraries.

As can be seen below it provides Circuit width , height above runway and quite a bit of other data , it also enables precision ILS style approaches and landings at "all" runways that exist in the simulator database (approx 24,491 airports), it ensures that the standard rectangular circuit can be flown with absolute precision .

Cheers Karol

Overview of instrument

Edited January 6, 2021 by COBS

[jon b 2,041]

I think the original question relates to a light aircraft circuit, however the Boeing heavy jet (747/787) circuit procedure is as follows...

A continuous 180 degree turn from upwind to down wind 

Downwind at 1500ft normally, at around 2-2.5nm from the runway, apply 3 times the drift.

Speed  approximately 180kts (flap 10 speed + 10kts 747, flaps 5 speed 787)

Abeam the threshold gear down flaps 20 , start timing... fly for a further 15 seconds for each 500ft of height , so for 1500ft 45 seconds +- 1 second for each kt or head/tail wind

At the end of the time flaps 30 and start continuous turn to finals while starting a descent of around 300fpm

[hedbonker 5]

Thank you all very much!

[COBS 25]

The "Synthetic ILS" instrument also enables other styles of airport approaches to be conducted , in instances where an Radio NAVAID ILS is being conducted an Intercept position can be created any distance prior to the touchdown spot on the "extended Runway Centreline"  , here 7.0 nm was entered , intercept position indicated by blue arrow , it makes runway alignment and ILS capture much easier.                                                                                                                                                                        ..NOTE the Target  "S-Ht "  value 2,225 ft  (height above Runway) is a fixed value based on both set , Intercept distance and currently set Glideslope  angle , in other words you descend down from cruise height to 2,225' to precisely capture the Glideslope at the intercept position.

Cheers Karol

[birdguy 3,943]

When I was transitioning into ground aircraft (my first lessons were on floats) in a Cherokee 140 the rule was to turn base from your downwind when you could just see the end of the runway over your left shoulder.

Noel