MEA/OROCA/vectoring altitudes

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JULIETTE
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MEA/OROCA/vectoring altitudes

Post by JULIETTE »

Hi,

Looking for a quick refresher on Off airway Obstruction clearance altitudes.

If I am planning an off airway route through a mountainous region, and am looking for the minimum altitude I can file and fly IFR, what is the most accurate way to do this.

Way back when I did my training, I was taught to plot my course and then measure my 5 miles each side, add 2000’ to feet the highest altitude for mountainous regions, and that would give me my MOCA. Then there was a formula to calculate VHF reception altitude. How do I make that calculation again?

If I do those calculations, would it be likely that the altitude that I get would be good to file with ATC? Is there any place I can find what their min vectoring altitude for a segment would be?

Specifically I am looking at a routing of YYC.CONER.ERVYN.CYCG if anyone wants specifics.

Thanks!!
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Scuderia
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Re: MEA/OROCA/vectoring altitudes

Post by Scuderia »

JULIETTE wrote: Mon Dec 28, 2020 11:16 amThen there was a formula to calculate VHF reception altitude. How do I make that calculation again?
725.37 wrote:For line of sight navigation aid reception distance for ground installed aids, the minimum reception altitude may be calculated by calculating the square root of an altitude above the navigation aid and multiplying the result by 1.25 (Sq. root 3000 ft. is 54.7 x 1.25 = 68 miles). The MEA will be established to the nearest higher 100 foot increment.
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thenoflyzone
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Re: MEA/OROCA/vectoring altitudes

Post by thenoflyzone »

YYC-YCG is only 177nm.

You could use the 100 nm safe altitudes published on YYC and YCG charts, take the highest one, round it out to the higher thousand, adjust for westbound alt/FL, and call it a day.

I believe it will give you a minimum safe altitude of 14,000 ft. Based on your routing, why even bother with VHF reception altitude? You're flying an RNAV routing.

Besides, the beauty of flying IFR in controlled airspace is that even if you file say 8,000ft, ATC will climb you to their minimum safe altitude anyway (which might be higher than 14,000ft). This way you won't become another statistic of CFIT.

Usually minimum vectoring altitudes (MVA) are only available in and around Terminal control units and other busier airports within radar coverage. I don't think YCG has radar coverage to the ground, so therefore probably doesn't have MVA's published around it either. Closest radars around YCG are at YYC and Kamloops. Those are pretty far.
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16SidedOffice
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Re: MEA/OROCA/vectoring altitudes

Post by 16SidedOffice »

File V305 YXC V300 ERVYN at the MEA, Center will do the rest and if available, offer you direct ERVYN and lower as they can.
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pinchbiscay
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Re: MEA/OROCA/vectoring altitudes

Post by pinchbiscay »

During my training, I learned to draw a path, measure five miles on each side, and then add two thousand feet to the greatest height for hilly terrain to arrive at my minimum operational clearance altitude (MOCA). Then, an equation was developed to determine the optimal height for VHF reception. In what way do I re-calculate the variables?
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