Circling Calculations

[Dadanawa]

Trying to create a workable spreadsheet for circling calculations.

So far this is what I've come up with.

Entries in yellow cells, calculations in blue cells.

Comments, questions, and suggestions are welcome.


[IMG][/IMG]

[Checkboard]

Why?


... and you're too close to the runway. Should be about 1.5 to 1.7 nm abeam.

[Dadanawa]

Distance from runway depends on turn-radius for given speed. As speed increases, turn-radius increases, and distance from runnway increases.

Why ?

Takes the guesswork out during a procdure that is not commonly flown.

[Goldenrivett]

Hi Dadanawa,

You did bother to draw this circuit out before posting your maths - didn't you?

If the downwind heading is 281 degs and the wind is from 269 degs at 10 kts, why are you bothering to circle to land with a 10 kt tailwind on finals?

If the circling direction is Left hand circuit (/L) why are you turning Left (253)? You would then surely be turning Right to turn onto finals. (What we used to call a Right Hand Circuit).

If I was flying at 1500 ft agl I would fly from abeam THR to base turn for 45 secs in still air. Since I have a 10 kt headwind flying downwind, then I'd turn at 55 secs (not at 33).

I think you'll find you need a mental picture to fly circuits - not a list of numbers.

[vilas]

There is some confusion. I think you mean left break and not circle left? Why 30 degrees offset? should be 45 degrees and 30 seconds.

[donpizmeov]

Circling is a visual procedure. More time with eyes outside and less looking at an app might be a step in the right direction.

[Dadanawa]

Yes Vilas,


What I mean is a left turn to right downwind.


And yes, in this particular case there is a tailwind. (Just entered arbitrary figures)


Separate sheet for 45 degree break.


I'd say figures can be entered quickly once you get the ATIS. Might take 20 seconds.

[galaxy flyer]

If you can't make this work in your head and translate it into a flight path in the plane, you need to reconsider your career choice. How are you going to use this spreadsheet on a rainy afternoon just below the clouds in a jet?

GF

[vilas]

At 1500ft do a normal circuit as in most aircrafts done at 2.5 nm downwind displacement. Japs do at 2nm. You don't need a spread sheet.

[B737900er]

Icao/Pans -ops we fly 4.2nm for 180kts or 5.28 at 205 knots.

[Matey]

Reminds me of the situation in my company a while back when the PM noticed PF rummaging in his flight bag when downwind on a visual approach in manual flight with no hands on the controls. When challenged he stated he was looking for his calculator to work out timing from abeam the threshold before turning finals!

[khorton]

In the real world, the wind changes as the altitude changes when descending. These changes are sometimes quite significant. I find it works best to look out the window, and vary the bank angle and descent rate as required so the aircraft ends up where I want on short final.

[compressor stall]

The primary instrument in a visual approach is the window.

[harpf]

1) Doing a bit of math my help the beginner to understand the limitations and trade space available to when flying the maneuver. The FAA has taken a crack at this for no wind with for us when setting up the A-E category minimums. These have recently been revised as they were a bit optimistic about what could be accomplished safely.


2) As a GA pilot who fly's a bit of IFR into small airport, I have performed as many real (IFR and not training) circle to land as I have real ILS approaches.

[Capt Fathom]

Hill? What hill?

[vilas]

B737900er

Icao/Pans -ops we fly 4.2nm for 180kts or 5.28 at 205 knots.

Really? I think you have misunderstood the PANS OPS. It gives the limit of visual manoeuvring area available. Why would you place yourself at the edge of the area? Even if you did turn downwind at 205kts it will place you 2.34nm on downwind.

[B737900er]

Vilas

Sorry, I didnt make myself clear there what I meant is those are the limits we fly to. As you said rightly said, you would be well within those limits.

Timing 3seconds per 100' Agl +\- wind

[avoka]

There is not +\- wind correction for circling approach in according to Airbus documents.
There was the thread here regarding this correction
Safe flights

[Goldenrivett]

There is not +\- wind correction for circling approach in according to Airbus documents.

Can somebody please explain how the physics of ground speed changes if the only difference is that some aircraft now have a computer between the pilot and the control surfaces.

[vilas]

avoka
There is no such document by airbus. You can read your FCOM the timing is very much there.Also read the thread again fully.