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VFR visibility under 140knots

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VFR visibility under 140knots

Old 18th Aug 2016, 20:40
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VFR visibility under 140knots

Should VFR visibility at 140knots or less be 1500m or should it be 5000m? The attached pictures seem to say different things?
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Old 18th Aug 2016, 21:16
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? - they both say 1500 to me, taking into account the footnote on one of them.
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Old 18th Aug 2016, 22:50
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SERA5001:

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Old 19th Aug 2016, 00:10
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Reference above table at and below 3000feet.

As far as I recall. The CAA have derogated out of the cloud separation requirements in class D, which remain as clear of cloud in sight of the surface.
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Old 19th Aug 2016, 00:41
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The SVFR minima in Canada is 1 statute mile (5,280 ft., or 1,609 metres), regardless of airspeed.

A factor which seems to have been overlooked by legislators is a 140 kt IAS with a 40 kt tail wind, (not uncommon), your ground speed will be around 180 kts. i.e. 3 miles per minute.

Yes, oddly, ground visibility in Canadian METARs are reported in statute miles, yet flight planning and distances on charts is in nautical miles. Elevations on charts are indicated in feet, yet Canada has officially been metric since 1975. What a country! The U.S.A. has only recently changed to reporting temperatures in Celsius on METARs..
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Old 19th Aug 2016, 07:45
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A factor which seems to have been overlooked by legislators is a 140 kt IAS with a 40 kt tail wind, (not uncommon), your ground speed will be around 180 kts. i.e. 3 miles per minute.
I think this ismore for seeing other aircraft and the relative speeds will be the same regardless of wind
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Old 19th Aug 2016, 08:49
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The UK exemption (valid until 30 Sep 2016) for Class D is ORS4 No.1158: http://publicapps.caa.co.uk/docs/33/1158.pdf

Class G VFR criteria are covered in ORS4 No.1067:
http://publicapps.caa.co.uk/docs/33/ORS4No1067.pdf
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Old 19th Aug 2016, 17:52
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Gert, the footnote is only asterisked to apply to F and G. So there still seems to be a conflict in acde.

Beagle, neither of my diagrams seem to reflect your table's statement that below 3000ft in abcde airspace, an aircraft should be 1000ft separate from cloud. Any idea why?
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Old 19th Aug 2016, 20:46
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Read the ORS links I provided!
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Old 19th Aug 2016, 21:14
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I did but they only seem to deal with class D and G airspace?
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Old 20th Aug 2016, 10:15
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The way I understood the rules were visibility 5km, 1500m vertical distance from clouds... but my theory is now quite a way back.....
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Old 20th Aug 2016, 10:56
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1500m vertical distance from clouds
So no VFR if the cloudbase is below 4950 feet? That should cut congestion down a bit...
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Old 20th Aug 2016, 21:47
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Originally Posted by ShyTorque View Post
So no VFR if the cloudbase is below 4950 feet? That should cut congestion down a bit...
sorry, should be horizontal distance - went flying and can no longer tell my up from down...... at least that's my excuse.... well, some aerobatic blighter was trying to teach me up is down, black is white and that my lunch really should be worn as an accessory on my shirt...... ;-)
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Old 22nd Aug 2016, 21:49
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Originally Posted by evansb
Yes, oddly, ground visibility in Canadian METARs are reported in statute miles, yet flight planning and distances on charts is in nautical miles. Elevations on charts are indicated in feet, yet Canada has officially been metric since 1975. What a country!
New Zealand isn't much different:

Altitude: Feet
Elevation: Feet
Visibility: Metres/Kilometres
VFR reporting: Nautical Miles (e.g. "ABC is X miles from the airfield")
Temperature: Celsius
Atmo Pressure: QNH
Runway length: Metres
Weight/Balance: Kilograms

I would do airspeed but I've flown in NZ registered aircraft with knots, mph and km/h on the ASI. Fuel is measured in litres but some of the weight and balance calculations are done in pounds so converting litres to fuel pounds then to kilograms is a pain in the .

Apologies for the thread drift.
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Old 23rd Aug 2016, 11:42
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"A factor which seems to have been overlooked by legislators is a 140 kt IAS with a 40 kt tail wind, (not uncommon), your ground speed will be around 180 kts. i.e. 3 miles per minute."

Won't this mean the clouds are moving at the same speed as you and therefore it won't affect the time to spot other aircraft? Not sure groundspeed is relevant?
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Old 23rd Aug 2016, 12:47
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Not sure groundspeed is relevant?
It is with regard to obstacles.
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