Class C Airspace Discussion

"skym" wrote in message
oups.com...

Interesting query. At first I wondered how this situation ever arises,
then I remembered my VFR flight into Troutdale (TTD) which is in a
class D airspace that partially underlies and actually seems to invade
the overlying Class C of Portland (PDX).


No invasion. There is a hierarchy of airspace, lower classes of airspace
give way to higher classes.


PART 71-DESIGNATION OF CLASS A, B, C, D, AND E AIRSPACE AREAS; AIR TRAFFIC
SERVICE ROUTES; AND REPORTING POINTS

§ 71.9 Overlapping airspace designations.

(a) When overlapping airspace designations apply to the same airspace, the
operating rules associated with the more restrictive airspace designation
apply.

(b) For the purpose of this section-

(1) Class A airspace is more restrictive than Class B, Class C, Class D,
Class E, or Class G airspace;

(2) Class B airspace is more restrictive than Class C, Class D, Class E,
or Class G airspace;

(3) Class C airspace is more restrictive than Class D, Class E, or Class G
airspace;

(4) Class D airspace is more restrictive than Class E or Class G airspace;
and

(5) Class E is more restrictive than Class G airspace.



I was on flight following
from the southwest and couldn't find the TTD airport, so PDX approach
was kindly giving me help... "it's about 2 miles at 12 o'clock."
(Don't laugh; they're not always easy to find.) When he told me to
contact TTD tower, I got a rather exasperated reply on my callin that I
should have called them earlier. I meekly replied that I was with PDX
approach until then, and he said "Oh well, that was ok."
So, I guess I technically busted the Class D by not contacting them
while I was still talking to approach (within Class C) but was already
within 5 miles of the Class D airport. Frankly, since I was on radar
with approach control I felt it was safer for everyone to stay with
them until told to contact the local tower at TTD.


You can't bust Class D airspace while you're in Class C airspace. If you
were two miles southwest of TTD between 1700 and 4000 MSL you were in Class
C airspace. If you were below 1700 you were in Class D airspace.

Enquiry and reply can be found at...

http://www.mikeg.net/library/files/classc

On 10 Apr 2006 18:29:51 -0700, "Mike Granby" wrote
in .com::

The essence of the reply is that
(i) it is necessary to be in contact with the specific TRACON
responsible for the Class C rather than just any old ATC facility;


http://ecfr.gpoaccess.gov/cgi/t/text....1.3.10.2.4.17
§ 91.130 Operations in Class C airspace

(c) Communications. Each person operating an aircraft in Class C
airspace must meet the following two-way radio communications
requirements:

(1) Arrival or through flight. Each person must establish two-way
radio communications with the ATC facility (including foreign ATC
in the case of foreign airspace designated in the United States)
providing air traffic services prior to entering that airspace and
thereafter maintain those communications while within that
airspace.

From the words of the regulation above it is clear that the words 'the
ACT facility' refer to the ATC facility with responsibility for flight
within their Class C airspace. But it could have been worded so that
there was less ambiguity.

and (ii) that the receipt of VFR advisories does not absolve a pilot of his
responsibility to contact that TRACON before entering the airspace and
that he would therefore be in violation if he entered without so doing.

It is difficult to anticipate a situation in which Radar Traffic
Advisory Service within a Class C airspace is being provided by a
facility other than the one which has responsibility for that Class C
airspace.

As I say, links to PDFs to follow.

Thanks for your effort in seeking official clarification of this
issue, sharing it here, and making the original documents available
on-line.