Both countries have a speed limit of 250 knots below 10,000', unless you're flying an airplane so crazy that it would be unsafe to operate it at a lower speed. In Canada the next speed limit restricts you to below 200 knots below 3000' within ten nautical miles of a control zone. In the US, it's below 200 knots below 2500' within 4 nm of the airport inside a class Charlie or Delta control zone. But in a class Bravo control zone, fill your boots at up to 250 kts. I'm writing Charlie out in full for the US version because that's how they say it (we say "cee"). That will maybe help me remember.
According to a document I read recently, the low altitude speed limits were established to reduce the severity of bird strikes, but I'm guessing that was just for the 250 kt ones, because I can't see that the birds would pay really close attention to which airspace they are in. The 200 kt speed limit is probably to help ATC control different speed aircraft.
Although the Americans have most of the same airspace letters as Canada, they don't really line up. They have class Bravo control zones whereas we only have class B airspace over 12,500'. If you pretend US Bravo is Canadian C you'll follow all the right rules, ensuring you have a clearance before entering the airspace. At 200 knots or below.
5 comments:
Dear Trix:
The 250 knot speed limit in the terminal area (Class Bravo) was introduced in the aftermath of the mid-air collision involving a UAL DC-8 and a TWA Connie over New York City in December of 1960.
The DC-8 was doing about 300 knots at the time of the collision and in some quarters this speed was viewed as excessive and a contributing factor.
See, e.g., HERE.
Regards,
Frank
Houston had a waiver for years allowing them to clear departures out at more then 250kts. Internet tells me it's canceled now.
Here's a very old link:
NOTAM
RE: In Canada the next speed limit restricts you to below 200 knots below 3000' within ten nautical miles of a control zone
---
I thought it was "within 10 nm of an airport" -- has something changed? The control zone version would require the pilot to know the control zone dimensions - something not necessarily included on IFR charts ...
Also, on departures where the final cruising altitude is above 10,000 feet, Canadian Regs. used to allow acceleration above 200 kts on departures. Is this still valid? I know they experimented with it in the USA (Houston) as well, but it looks like they cancelled that, judging by previous commnents.
But in a class Bravo control zone, fill your boots at up to 250 kts.
"Fill your boots"? Never heard that one before. I like it.
Frank is correct that the speed restriction has nothing to do with bird strikes, it was a direct result of the accident he cites. One note, it isn't just the terminal area, and it has nothing to do with airspace classification, the 250 knot restriction applies anytime you're below 10,000 feet, wherever you are,
Post a Comment