Since I'm not the math guru, I'm gonna ask, what would the maximum altitude need to be for todays pattern sequences?

And could it be less if at all?

Wana know where I'm going with this, Our Field has an airport nearby and I believe our current restriction is 400'.

Club members(officials) say no pattern because of this.

Thanks

If you fly at the limit (175 m or 574'), the maximum altitude is 496' to break the 60 degree rule. However, if you fly at 150 meters = 492' the maximum altitude is 426'. Therefore, if you fly a little closer you could be below 400'.

Vicente "Vince" Bortone

That's only when the plane is at center though...

You're going to have trouble keeping it under 400 feet on some turn around maneuvers.

Vince, I’m not sure how you did your calculations, but my calculations are as follows. At a distance of 150 to 175 meters (492’ to 574’) and an angle of 60 degrees the height at the intersection (max height) would be 854’ at the 150 meter mark and 994’ at the 175 meter mark.

Brett is correct that it would be even higher at the box ends.

Mike, though it’s not necessary or common to exceed the 60-degree line when one’s at the proper distance, I think it’s pretty clear that most pattern fliers will not keep below the 400’ level. The possible exception to this would be sportsman.

Keith B

Just for grins I did some more calculations. Turns out that the max height based on the 60 degree rule at the box end when flying 175 meters out is 1988 feet!!!

Keith B

We have a contest at a field that has the exact same problem, 400' limit because of overflying military aircraft.

Put it this way...its not uncommon for us to get a visit by either the MP's or the civilian police during an event Fortunately the CD has a magical way of dealing with it

FAI and Masters are by far the worst culprits, but there is no way to fly the sequence in less than 400' altitude.

I am sorry. I am wrong in my calculations. At 150 meters = 492' the max altitude is 852'. At 175 meters = 574' the maximum altitude is 994'. Way over the 400'. I used sin60 and should be tan60 = 1.73. The altitude is 1.73 x distance from the pilot to the fly line assuming that you neglect how tall is the pilot. If we want to be precise we should add the pilot height.

Looks like it is going to be almost impossible to keep the plane below 400'.

Vicente Bortone