"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.