Q: Flying BENEATH Class B/C/D Airspace

"john smith" wrote in message
...

The regs say you must communicate, have permission, a clearance, have a
transponder, etc to fly in any Class B/C/D Airspace.
The airspace is generally defined by the airport reference point altitude
and location on the field. For example the definitions state "from the
surface to..."
What requirements are there for flying BELOW the airport surface?
I know several airports with the requisite airspace that are located above
surrounding terrain where it would be possible to fly below the airport
surface.
What say the group?


The boundary of the airspace is generally defined by the airport reference
point but the altitude at that has nothing to do with the airspace. The
lower limit of a surface area is the surface of the Earth, you'll find it
quite difficult fly below the surface.

"Ben Hallert" wrote in message
oups.com...
Assuming you mean 'below the airspace'

Well, for one... there's the mode C veil. 30 miles from the primary
airport located in class bravo, mode C transponders are required and
must be transmitting altitude data.


Kinda true but aircraft not originally built with an electrical system are
exempt.

On Mon, 27 Jun 2005 23:15:06 GMT, john smith wrote:

The regs say you must communicate, have permission, a clearance, have a
transponder, etc to fly in any Class B/C/D Airspace.

No, you don't need a transponder to fly in D airspace. I do it all the
time.



-- all the best, Dan Ford

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On 27 Jun 2005 16:52:23 -0700, "Ben Hallert"
wrote:

Well, for one... there's the mode C veil. 30 miles from the primary
airport located in class bravo, mode C transponders are required and
must be transmitting altitude data.

Again, not always the case. I have often through the Mode C Veil
around Boston's Logan airport without a transponder. It is legal with
an airpcraft that was built without and has never been equipped with
an electrical system, like the Cub.


-- all the best, Dan Ford

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On Mon, 27 Jun 2005 18:27:47 -0500, "Hotel 179"
wrote:

To fly BELOW the airport surface is never recommended. Cumulo granite could
ruin your day

Lebanon NH airport is located on a ridge or butte. It would indeed be
possible to fly below the RUNWAY surface, but of course that's not
what the Class D requirement suggests. It extends from the surface of
the ground at any point to 2,500 feet (whatever) above that surface.
So I reckon that in the case of Lebanon, the top of the Class D tuna
can would be rippled: higher where the airport itself is situatated.


-- all the best, Dan Ford

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On Mon, 27 Jun 2005 16:51:59 -0700, "Bob Gardner"
wrote:

Note that AIM 3-2-5 says that Class D "generally extends from the surface to
2500 feet above airport elevation," thus making a distinction between the
surface and field elevation.

Ah! Okay, scratch my presumption that the roof of the Delta airspace
might be rippled



-- all the best, Dan Ford

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Cub Driver wrote:

On Mon, 27 Jun 2005 18:27:47 -0500, "Hotel 179"
wrote:

To fly BELOW the airport surface is never recommended. Cumulo granite could
ruin your day

Lebanon NH airport is located on a ridge or butte. It would indeed be
possible to fly below the RUNWAY surface,
Or at least below the altitude of the runway surface.g

You can also fly below the altitude of the Leadville runway surface.
The only question is how close a proximity you are to said runway.
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

"Cub Driver" wrote in message
...
[...]
So I reckon that in the case of Lebanon, the top of the Class D tuna
can would be rippled: higher where the airport itself is situatated.

The airspace is not "rippled". The maximum elevation is generally 2500 feet
above the *airport*, even as the airspace itself extends to the surface,
wherever that surface may lie.

On Tue, 28 Jun 2005 11:24:21 -0700, "Peter Duniho"
wrote:

The airspace is not "rippled". The maximum elevation is generally 2500 feet
above the *airport*, even as the airspace itself extends to the surface,
wherever that surface may lie.

Point taken.

I will remember that, the next time I am coasting over the Delta
airspace.


-- all the best, Dan Ford

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