Using the magenta circles

"Ace Pilot" wrote in message
om...

common use is doing T&Gs in the pattern below 700 feet AGL when the
weather is marginal. Other uses?

1. The altitude where controlled airspace begins can be a factor for an IFR
pilot selecting an airport at which to fly an instrument approach if he is
concerned about airplanes legally flying a traffic pattern 1 foot below him
when he breaks out of a cloud.

2. In areas with unusual and predictable weather patterns, i.e. a very thin
marine fog layer, some pilots depart IMC in Class G airspace in anticipation
of breakout out on top into VMC conditions before entering controlled
airspace -- not necessarily wise but legal nonetheless.


--
Richard Kaplan, CFII

www.flyimc.com

Thanks, Richard. That's somewhat along the lines I was wondering
about. However, both of the cases you listed are for IFR flights.
Makes me wonder why, if this information is more useful to the IFR
pilot than the VFR pilot, is it on sectional charts when it sounds
like it would be more useful on low level enroute charts (although,
I'll be the first to admit that I have a sectional or WAC available
when flying IFR).

"Richard Kaplan" wrote in message ws.com...
"Ace Pilot" wrote in message
om...

common use is doing T&Gs in the pattern below 700 feet AGL when the
weather is marginal. Other uses?

1. The altitude where controlled airspace begins can be a factor for an IFR
pilot selecting an airport at which to fly an instrument approach if he is
concerned about airplanes legally flying a traffic pattern 1 foot below him
when he breaks out of a cloud.

2. In areas with unusual and predictable weather patterns, i.e. a very thin
marine fog layer, some pilots depart IMC in Class G airspace in anticipation
of breakout out on top into VMC conditions before entering controlled
airspace -- not necessarily wise but legal nonetheless.

It is on the IFR charts because -- at least in theory -- the information
helps VFR pilots determine where they can legally scud run and at what
airports they can legally fly a standard 1000-foot pattern on a marginal VFR
day. Whether that is safe or whether VFR pilots actually are aware of or
follow these rules is another matter.

The distinction between a 700-foot transition zone or a 1200-foot transition
zone basically helps VFR pilots to determine if they can fly a standard
800-foot or 1000-foot pattern on a day when there is a 1000-foot ceiling.
The answer is yes for airports with 1200-foot transition zones and no for
airports with 700-foot transition zones.

A related issue has to do with Class E Surface Areas -- generally commuter
or regional airlines are permitted only to fly at airports which have Class
E Surface Areas and thus -- at least in theory -- where it should not be
possible for an IFR airplane to break out of a cloud and find a VFR airplane
1 foot below. This means that on marginal VFR days it is at least
theoretically safer for an IFR pilot to land at an airport with a Class E
Surface Area than with Class G airspace on the surface.

--
Richard Kaplan, CFII

www.flyimc.com

The difference between class E and G airspace is that ATC
cannot control traffic in class G (thus... it's uncontrolled)...
By lowering the floor of the class E (in which ATC can control
aircraft) over small airports, IFR flights can remain under
ATC control to a lower altitude, thus facilitating the IFR
approach process...

The fact that VFR minimums in class G are 1 mile and
clear of clouds is not to encourage VFR pilots to go fly
in that, but to make it legal for instrument pilots to complete
approaches where the visibility minimums are 1 mile in the
class G airspace... Ever wondered why SVFR minimums are
1 mile and clear of clouds... Same reason...


John Price
CFII/AGI/IGI
http://home.att.net/~jm.price


"Ace Pilot" wrote in message
om...
A friend recently asked me to explain the magenta circles seen around
numerous airports on sectionals. It got me to thinking about how
useful they are. Personally, if the weather isn't good enough to fly
VFR in Class E airspace, I'm not going to fly VFR, even if it is legal
in Class G airspace. So, for me, it is pointless knowing where the
boundary is between Class E and Class G airspace.

But I was curious to know if there are pilots that take full advantage
of this distinction. Does anyone actually make use of the Class E/G
boundaries depicted on sectionals? If so, how? I suspect the most
common use is doing T&Gs in the pattern below 700 feet AGL when the
weather is marginal. Other uses?

"john price" wrote in message
...

The fact that VFR minimums in class G are 1 mile and
clear of clouds is not to encourage VFR pilots to go fly
in that, but to make it legal for instrument pilots to complete
approaches where the visibility minimums are 1 mile in the
class G airspace...


VFR minimums have nothing to do with IFR approaches.

Sorry... Forgot to mention the concept of cancelling in
the air once airport is in sight... NY likes it much better
that way...

John Price
CFII/AGI/IGI
http://home.att.net/~jm.price


"Steven P. McNicoll" wrote in message
ink.net...

"john price" wrote in message
...

The fact that VFR minimums in class G are 1 mile and
clear of clouds is not to encourage VFR pilots to go fly
in that, but to make it legal for instrument pilots to complete
approaches where the visibility minimums are 1 mile in the
class G airspace...


VFR minimums have nothing to do with IFR approaches.

"john price" wrote in message
...

Sorry... Forgot to mention the concept of cancelling in
the air once airport is in sight... NY likes it much better
that way...

Be careful there... if controlled airspace exists below 1200 feet and you
break out of the clouds at 1000 feet with the runway in sight so you cancel
IFR, you have just broken the minimum cloud separation requirement for VFR
flight.

--
Richard Kaplan, CFII

www.flyimc.com

"john price" wrote in message
...
Sorry... Forgot to mention the concept of cancelling in
the air once airport is in sight... NY likes it much better
that way...

This obviously helps if your cancelling lets the following aircraft carry on
with the approach. It also helps if you are the following aircraft, and the
pilot in front is on the ground or in sight, without having canceled.

If you do that, would it be helpful to let ATC know you're continuing the
(now, practice) approach under VFR?

-- David Brooks

I'm talking about real approaches... With real weather...

John Price
CFII/AGI/IGI
http://home.att.net/~jm.price


"David Brooks" wrote in message
...
"john price" wrote in message
...
Sorry... Forgot to mention the concept of cancelling in
the air once airport is in sight... NY likes it much better
that way...

This obviously helps if your cancelling lets the following aircraft carry
on
with the approach. It also helps if you are the following aircraft, and
the
pilot in front is on the ground or in sight, without having canceled.

If you do that, would it be helpful to let ATC know you're continuing the
(now, practice) approach under VFR?

-- David Brooks

"David Brooks" wrote in message
...

This obviously helps if your cancelling lets the following aircraft
carry on with the approach. It also helps if you are the following
aircraft, and the pilot in front is on the ground or in sight, without
having canceled.

If you do that, would it be helpful to let ATC know you're continuing
the (now, practice) approach under VFR?


No.