I've briefly searched the CARs and I haven't found the answer to my question so I decided to pick your brains.
I have forgotten when to round up to the next highest cct altitude in hundreds of feet.
For example: when the airport elevation is 135 feet is the cct 1200 ft or 1100 feet?
One would logically think that it's 1100 due to the ground elevation being less than 149 feet but from what I remember it doesn't work that way. If I remember correctly the cutoff is the 19 foot mark? Not certain.
So with the cutoff being the 19 foot mark the cct alt would actually be 1200 ft.
I know for certain it is not the mathematical way of rounding up, it's some arbitrary number that was chosen but I can't remember it.
Any help?
Circuit altitude
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PositiveRate27
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Re: Circuit altitude
Off the top of my head, in the IFR world, you round down at 20 and below and round up above that. Can't remember what the rule is for VFR circuit altitudes...
Re: Circuit altitude
it doesn't say to round the circuit altitude at all. in fact I don't think CARS specifies a circuit altitude. For some airfields it's in the CFS.
I've never seen a rule that circuits have to be at a whole number of hundreds of feet, and at my local airfield they're not.
I've never seen a rule that circuits have to be at a whole number of hundreds of feet, and at my local airfield they're not.
Last edited by photofly on Sat Nov 16, 2013 5:42 pm, edited 1 time in total.
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Dutchpilotguy
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Re: Circuit altitude
Hmmm... I can't seem to find anything either with the exception of "1000 ft AAE"
I recognize that your question is for the purposes of rounding, and so I'll answer it the way I see it using a little bit of airmanship.
a) in the absence of a specific answer, I would round just the same as I would in day-to-day math, while I WOULD FAVOR ROUNDING DOWN.
Why? Well there is typically nothing happening BELOW the circuit, and so fudge factor is available downward. There are however all kinds of folks zinging around at 500' (ish... if at all) above circuit altitude who are generally blind to what happens below them thanks to the airplane itself. That being said, where I did most of my training, the Airport Elevation was (and interestingly enough, still is...
) 3940'. However, the circuit altitude is PUBLISHED in the CFS as 5000' ASL, so in that case your question is answered.
After my little search here which I will admit is NOT exhaustive, I would say that if my airport did not have a published altitude, and I were, say, on a flight test; the exact altitude of 4940' for the circuit would be appropriate (+/- 100 feet for tolerance, so call it 5000' and you're still passing). Also, I can't think of examiners I know who would get too worked up about that rounding. But if you can hold 5000', why not hold 4940' and be a pro star?
Fly the numbers as published/instructed and have a blast doing it!
I recognize that your question is for the purposes of rounding, and so I'll answer it the way I see it using a little bit of airmanship.
a) in the absence of a specific answer, I would round just the same as I would in day-to-day math, while I WOULD FAVOR ROUNDING DOWN.
Why? Well there is typically nothing happening BELOW the circuit, and so fudge factor is available downward. There are however all kinds of folks zinging around at 500' (ish... if at all) above circuit altitude who are generally blind to what happens below them thanks to the airplane itself. That being said, where I did most of my training, the Airport Elevation was (and interestingly enough, still is...
) 3940'. However, the circuit altitude is PUBLISHED in the CFS as 5000' ASL, so in that case your question is answered.After my little search here which I will admit is NOT exhaustive, I would say that if my airport did not have a published altitude, and I were, say, on a flight test; the exact altitude of 4940' for the circuit would be appropriate (+/- 100 feet for tolerance, so call it 5000' and you're still passing). Also, I can't think of examiners I know who would get too worked up about that rounding. But if you can hold 5000', why not hold 4940' and be a pro star?
Fly the numbers as published/instructed and have a blast doing it!
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PositiveRate27
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Re: Circuit altitude
Just out of curiosity, is that a reference out of the CFS or is that a mutually agreed altitude from the local pilots who fly there?pdw wrote:Ours is 321' elevation and circuit height is 1300'.
Re: Circuit altitude
It's always been 1300'. CYSN Airport elevation is 321', as is rwy 06 threshold, ... and rwy 24 threshold is 319'.
Re: Circuit altitude
I'm sure circuit altitude should be 1321 feet 6.2498 inches.
Who are we kidding here?
Who are we kidding here?
Re: Circuit altitude
Don't encourage the pedantsphotofly wrote:I'm sure circuit altitude should be 1321 feet 6.2498 inches.
Who are we kidding here?
Re: Circuit altitude
That's a good point Keenflyer, it's not necessary to split hairs over this approximated 1000' altitude as long as calibrating-it is uniform among all aircraft.
Rounding to the nearest 100' on the altimeter kept it so much simpler in the circuit.
The 1000' AGL circuit height target, .. when abiding to the closest 100'msl increment chosen, ensures circuit height to be at least 950' AGL up to or less than 1050'.photofly wrote:Who are we kidding here?
Rounding to the nearest 100' on the altimeter kept it so much simpler in the circuit.
