- General Airspace Commentary
Information for Regulations - General Airspace
There are a number of regulations concerning
how close you may fly to various dangerous or
noise-sensitive locations. You will probably need to put some
effort into remembering all the numbers. I have made some
pictures illustrating some of the regulations, but be sure to
read the CARs linked to the different questions, in order to
see the exact rules. Notice that you are supposed to be TREE
thousand feet over burning TREES -- that one isn't on the
PSTAR but it has been on the private written exam. And
here's a joke about overflight of
is anywhere that has mostly buildings and
streets on the ground. The downtown area of a city or town, a
suburb, an industrial park, and a factory all constitute built
up areas. Furthermore, people are not very good at judging the
height of an airplane overhead. Your registration is
painted in large letters underneath your wing. If you
annoy people on the ground with your airplane, they will write
down your registration and call Transport Canada. It's
an easy way to get a fine and a violation on your licence.
Avoid repeated overflight of populated areas at minimum
altitudes. The above altitudes represent how far you must fly
above the tops of the fire, animals, or buildings, NOT the
height ASL shown on your altimeter.
The rules for weather minima depend on your
altitude, whether it is day or night, and whether you are
flying fixed wing (airplanes) or rotary wing (helicopters).
The pictures here illustrate the Canadian rules from CARs
602.114 and 602.115. The United States rules are
slightly different, but I won't discuss them here.
The basic rule for vertical/horizontal/visibility is
500'/2000'/1 mile. Here are some tricks to help you
remember. VFR aircraft must remain 500' vertically
from cloud: that's 500' clearance above and below. That's
not too hard to remember, because five hundred feet per minute
is a normal rate of descent or climb, what you see on the VSI
whenever you go up or down. Just remember "500'
up or down." Horizontal cloud clearance is the
distance clouds must be from you in any direction at your
altitude, or how far you have to pass a cloud off to your
side. In uncontrolled airspace that's 2000'
horizontal separation, or a third of a mile. I don't know
of a clever way for you to remember this, unless it helps to
know that two thousand feet is the length of a typical small
runway, the distance a sex offender must stay away from
schools under Iowa law, or the distance a colonial cannon
called a minion could fire a three pound ball. I didn't
think so. Just remember two thousand feet.
Visibility is how far you must be able to see forward in
flight, through haze, mist, rain or other obscuration. In
uncontrolled airspace, that distance is one mile
Flight below 1000' agl is a special case. If you're
flying less than 1000' above the ground, it's probably because
the weather is too bad to fly higher. The rules acknowledge
this and no longer specify a particular distance you have to
stay from cloud, so long as you remain clear of cloud.
But the rules also acknowledge that "scud running,"
as this is called, is dangerous, so the normal visibility
requirement doubles to 2 miles visibility.
Helicopters are more manoeuverable, and can stop their forward
motion, so their pilots are allowed half the visibility
required of airplane pilots, and helicopters can legally fly
below 1000' agl with 1 mile visibility.
a control zone, think of the number three. A
control zone is typically busier than uncontrolled airspace,
so the minima are higher. The "500' up or down"
rule is the same, but both the horizontal cloud distance and
visibility requirements triple in a control zone, so
the minimum requirements become 500' vertically from
cloud, 1 mile horizontally from cloud, and 3 miles
visibility. It so happens that three thousand feet agl
is the typical height of a control zone, too.
Night flight is another special case. You can't actually
see the clouds at night, but the cloud clearance rules
are the same as in the daytime, wherever you are. The
visibility requirement at night is always three miles,
regardless of whether you are in controlled airspace,
uncontrolled airspace, above
or below one thousand feet, in a helicopter or in an
Here's a question for you. Looking at the aircraft in the
night picture, tell me if it is coming towards you or away
from you, and whether you should turn to the right, turn to
the left, or hold your course if you saw those lights in front
of you at night. Click on the picture to see the answer.
To separate aircraft flying in opposite directions, the
cruising altitude orders specify permissible altitudes
for any given direction of flight. Altitudes are assigned
according to the magnetic orientation of the aircraft's
track over the ground, not according to the
heading (the way the airplane is pointing. That is because
aircraft of different speeds are affected differently by the
wind, requiring different headings to maintain the same
track. Within 3000' of the ground, the cruising altitude
orders do not specify altitudes for VFR flight. Above
3000' agl, you should travel at an altitude matching the
Altitudes to 18,000' ASL
Aircraft Magnetic Track
Odd thousand feet, plus 500' ASL
5500', 7500', etcetera)
Even thousand feet, plus 500' ASL
6500', 8500', etcetera)
For example, if you will be flying on a magnetic
track of 218 degrees, you need to select an altitude from
the right of the table.
I know three ways to
remember these rules. One is the saying "Odd
people fly east."
Another is the word ONE:
Some people just
think of the 0 being like the O in Odd, so they can
0 dd for directions of flight from
0 to 179
Whatever helps you remember that easterly directions
of flight correspond to odd altitudes (plus 500' for
The full rules are more complex, as they include
IFR traffic and traffic above 18,000' asl. You're not required
to know those rules for the private licence, but you can look
them up in CARs
Explanation of Regulations - General Airspace
ADIZ (Air Defence Identification Zone) is a region of
airspace that rings North America like a moat. There is
a map in the AIP-RAC 2.13, and the exact coordinates are in
the Designated Airspace Handbook. In order that approaching
hostile aircraft may be identified, aircraft that plan to fly
in the ADIZ must file a defence flight plan or defence flight
itinerary specifying the time and place that they will
penetrate the ADIZ. Any estimated change in time by more
than 5 minutes and any change in the route by more than
20 nm must be reported to ATS. The ADIZ rules
apply to all aircraft, regardless of speed or size. I
have abbreviated the rules here, see CARs
602.145 for the details.
is the definition of VFR flight: flight with visual
reference to the surface. VFR aircraft frequently fly in
control zones and aerodrome traffic areas. CARs
602.114 and 602.115.
Helicopter visibility rules are almost always half of
"Clear of cloud" leaves some room for judgement for
the pilot, but it is important to be clear. If you are forced
to fly below 1000' agl and dodge clouds, it is likely
that other aircraft are too. If you are too close
to a cloud, it's like coming suddenly from behind a corner.
Have you ever seen two people walk into each other as they
both came from opposite directions around a corner?
602.23 says only "No person shall create a hazard to
persons or property on the surface by dropping an object from
an aircraft in flight." This doesn't mean that you can't
drop objects, but that you must ensure they won't hurt
anyone nor damage anything.
need to read CARs
602.27 to know the rules for aerobatic flight, then pick
the most correct answer.
(1) You can
get permission to conduct aerobatic manoeuvers in controlled
airspace over an airport and you can conduct aerobatic
manoevers well over an airport in the uncontrolled airspace
above. But this is not the answer they want because there is
more to getting permission than just monitoring an appropriate
freqency, and there is not necessarily an appropriate
frequency to monitor if you are in uncontrolled airspace
overhead an airport.
(2) You must be over 2000' agl to do
aerobatics, unless you have a special permit, but you may
never do aerobatics over a built up area, such as the
suburban area of a city.
(3) This is a good answer, as it
combines the minimum legal visibility for aerobatics with
class F airspace. Some class F airspace is designated
(4) 1 mile is too low a visibility
for aerobatics, in any class of airspace.
pilots say, "Eight hours, bottle to throttle."
If it's been eight hours, but you are still under the
influence - still drunk or still hungover - CARs
602.03 forbids you to fly. The AIP recommends 24 to
48 hours after drinking, and some companies require 12.
Here is the definition of day from CARs
101.01: "day" or "daylight" means
the time between the beginning of morning civil twilight and
the end of evening civil twilight
Civil twilight is the period of time between sunset and
when the centre of the sun's disc is six degrees below the
horizon. You can't tell this by looking at the horizon or your
watch, you have to look it up. It typically last thirty to
forty-five minutes, but it can last all night in Canada,
depending on your latitude and season. You can get a list of
civil twilight times from Flight Services, or from the
Research Council. That last link is on the bottom of the
flight planning page under Sunrise/Sunset.
Note that it is still officially day AFTER the sun has gone
down, and day starts before the sun comes up. Remember: if
you can see the sun, it is definitely day.
This definition was changed in 2004 and the PSTAR question
was changed a couple of years later.
Here is the old rule, presented purely for historical
"day" - means the period beginning
one half-hour before sunrise and ending one half-hour after
sunset and, in respect of any place where the sun does not
rise or set daily, the period during which the centre of the
sun's disc is less than six degrees below the horizon.
Night is the period when it's not day, so it's the period
ffrom the end of evening civil twilight to the beginning of
morning civil twilight. You remember from seeing a sunset that
it doesn't instantly become dark the moment the sun
disappears. It doesn't instantly become official night,
purpose of CARs
602.24 seems to be to prevent pilots from spontaneously
joining up in formation. You don't want some stranger on
the highway driving right on your bumper, and you don't want
someone else in the air suddenly being on your wingtip. If
you prearrange the formation, it's legal, and you can fly side
by side wherever you have a clearance.
R in CYR stands for restricted. As it says in
601.04, no one may fly in restricted airspace without
permission. To get permission you must contact the
person responsible for that airspace, listed in a document
called the Designated
Airspace Handbook. Some people miss this question because
they automatically think they can't go in restricted airspace
at all, so disregard the idea of having permission.
Advisory airspace is class F airspace designated by
CYA. Advisory means that it's advice, not a
rule. The chart is telling you that a certain kind of activity
goes on there, and that if you are not participating in that
activity, you might not want to be there. The airspace where
you go with your instructor to practice stalls is probably
Class F advisory airspace designated T (for training)
or A (for aerobatics). Look on your VNC or VTA chart
12.13 This is word-for-word out
602.14. Note that while a helicopter may get within
500' horizontally of an obstacle, for airplanes
the clearance is 2000', the same clearance as for
clouds. I have heard of a fixed wing school that re-worded
this question, so be on the lookout.
Also straight from CARs
602.14. That's 500' above or horizontally, and it's
the same for helicopters and airplanes.
According to CARs
602.13, take-offs and landings are only permitted in built
up areas if you are landing at an airport, or if you are
involved in a police operation, or saving human life. This
means that no matter how big your backyard is, if you live in
the city, you're not allowed to land there without having it
certified as an airport.
As stated in CARs
602.34. Although 3500' is the lowest cruising altitude,
answer (4) is incorrect because aircraft above 3000' must
comply with the orders. 3100' is not a proper VFR cruise
12.17 As 290 is
between 180 and 359, an aircraft on a magnetic track of 290°
must be at an even thousand altitude, plus 500' (asl)
because it is VFR. (IFR traffic is assigned thousand
some reason, a lot of people get this wrong on the PSTAR, but
they always seem to recognize their error right away when I
show them. Read the question carefully. The track
is the path over the ground, the heading is the
direction the airplane is pointing. In the Southern
Domestic Airspace, magnetic track is used to dictate
altitude. (In the far north, compasses are not very
useful, and true track is used instead).
The three categories of people who may see your licence are
listed in CARs
103.12. "The Minster" refers to the Canadian
Minister of Transport, which in effect means his or her
delegates: Transport Canada inspectors. Other people might ask
to see your pilot licence before allowing you to rent their
aircraft, enter their office, or go through their security
gates. The difference is, if you don't want to show the
latter people your licence, you can legally walk away and not
show it to them. If the cops, customs or Transport Canada
officials ask to see it, you must show it, or face legal
This question is usually on the Private Pilot written exam,
(1) Low level airways are based at 2200' AGL.
Control zone transition areas are based at 700' AGL.
does extend upward from the surface of the earth, but not just
in designated airways.
(4) Up to, but not including,
(1) 2200' AGL represents the floor of class E airspace in
a low level airway.
(2) 700' AGL represents the floor of
transition areas around control zones.
(3) A control zone
normally is the controlled airspace around an airport. It
starts at the ground, where the runways are, and a typical
height for a control zone is 3000'. Many control zone tops are
higher or lower.
(4) The key here is that the control zone
starts at the ground. The top of the control
zone is a specified height above the surface.
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This page written 8 October 2002 by Robyn Stewart.
Last revised 21 September 2010.
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