ILS critical area when the tower is closed?

In this month's AOPA Flight Training magazine, I read an article
which implied there was still some requirement to remain clear of
the ILS critical area even when the tower was closed.

I've been looking through the AIM, and can't find anything like
this. It does say that when the tower is open, it will keep the
area clear when there is an aircraft past the FAF and the weather
is below 800/2.

Is there a rule which states that the ILS critical area must be
kept clear at any time when the tower is not in operation?

Can you please provide a reference?

Thanks,

--
Mark Hansen, PP-ASEL, Instrument Airplane
Sacramento, CA

Mark Hansen wrote:

Is there a rule which states that the ILS critical area must be
kept clear at any time when the tower is not in operation?

Rule or not, if keeping clear of the ILS critical area is very important
when the tower is open, wouldn't you agree that it probably is just as
important when the tower is closed?

--
Peter
























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"Peter R." wrote:

Rule or not, if keeping clear of the ILS critical area is very important
when the tower is open, wouldn't you agree that it probably is just as
important when the tower is closed?

(sent too fast)

Assuming, of course, that ceilings and/or visibility were low and an
aircraft were on an ILS approach.

--
Peter
























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I don't see what the tower being open or closed has to do with it. They
don't shut down the ILS when the last controller goes home, and a plane in
the restricted area distorting the glideslope signal is not a good thing.

Bob Gardner

"Mark Hansen" wrote in message
...
In this month's AOPA Flight Training magazine, I read an article
which implied there was still some requirement to remain clear of
the ILS critical area even when the tower was closed.

I've been looking through the AIM, and can't find anything like
this. It does say that when the tower is open, it will keep the
area clear when there is an aircraft past the FAF and the weather
is below 800/2.

Is there a rule which states that the ILS critical area must be
kept clear at any time when the tower is not in operation?

Can you please provide a reference?

Thanks,

--
Mark Hansen, PP-ASEL, Instrument Airplane
Sacramento, CA

On 11/20/2005 12:41 PM, Bob Gardner wrote:

I don't see what the tower being open or closed has to do with it. They
don't shut down the ILS when the last controller goes home, and a plane in
the restricted area distorting the glideslope signal is not a good thing.

Sure. But the tower is the controlling authority which is instructing
planes to hold clear of the ILS critical area.

If the tower is not in operation, who gives the order?

If the pilot on the ground is supposed to know when to hold clear,
how does he know? He may not even know a plane is using the
ILS. And besides, the tower only needs to keep it clear when the
weather is below 800/2, so does this go for the non-towered airport
as well?

Where is this defined?


Bob Gardner

"Mark Hansen" wrote in message
...
In this month's AOPA Flight Training magazine, I read an article
which implied there was still some requirement to remain clear of
the ILS critical area even when the tower was closed.

I've been looking through the AIM, and can't find anything like
this. It does say that when the tower is open, it will keep the
area clear when there is an aircraft past the FAF and the weather
is below 800/2.

Is there a rule which states that the ILS critical area must be
kept clear at any time when the tower is not in operation?

Can you please provide a reference?

Thanks,

--
Mark Hansen, PP-ASEL, Instrument Airplane
Sacramento, CA




--
Mark Hansen, PP-ASEL, Instrument Airplane
Sacramento, CA

Mark Hansen wrote:
In this month's AOPA Flight Training magazine, I read an article
which implied there was still some requirement to remain clear of
the ILS critical area even when the tower was closed.

The reason you're supposed to keep clear of the ILS critical area is
because your airplane can affect the glide slope beam. The presence or
absence of somebody in the tower doesn't change the physics of how
microwaves interact with metallic bodies.

On 11/20/2005 12:55 PM, Roy Smith wrote:

Mark Hansen wrote:
In this month's AOPA Flight Training magazine, I read an article
which implied there was still some requirement to remain clear of
the ILS critical area even when the tower was closed.

The reason you're supposed to keep clear of the ILS critical area is
because your airplane can affect the glide slope beam. The presence or
absence of somebody in the tower doesn't change the physics of how
microwaves interact with metallic bodies.

Thanks, but that wasn't my question. In fact, you snipped my question
out of the 'quote' which you included in your response.

--
Mark Hansen, PP-ASEL, Instrument Airplane
Sacramento, CA

"Mark Hansen" wrote in message
...

Sure. But the tower is the controlling authority which is instructing
planes to hold clear of the ILS critical area.

If the tower is not in operation, who gives the order?


Nobody.



If the pilot on the ground is supposed to know when to hold clear,
how does he know? He may not even know a plane is using the
ILS. And besides, the tower only needs to keep it clear when the
weather is below 800/2, so does this go for the non-towered airport
as well?


Well, if it's only a problem when an aircraft is on the ILS and it's below
800/2, and given that ATC isn't going to release an IFR departure if an
aircraft is on the ILS, then it doesn't appear to be a problem.



Where is this defined?


I don't believe it's defined anywhere.

On 11/20/2005 1:25 PM, Steven P. McNicoll wrote:

"Mark Hansen" wrote in message
...

Sure. But the tower is the controlling authority which is instructing
planes to hold clear of the ILS critical area.

If the tower is not in operation, who gives the order?


Nobody.



If the pilot on the ground is supposed to know when to hold clear,
how does he know? He may not even know a plane is using the
ILS. And besides, the tower only needs to keep it clear when the
weather is below 800/2, so does this go for the non-towered airport
as well?


Well, if it's only a problem when an aircraft is on the ILS and it's below
800/2, and given that ATC isn't going to release an IFR departure if an
aircraft is on the ILS, then it doesn't appear to be a problem.

I'm not sure that's the only time it's a problem. It just the minimum
that the tower is required to keep the area clear. I would expect that
ILS can be interfered with regardless of the current weather.




Where is this defined?


I don't believe it's defined anywhere.

Thanks,

--
Mark Hansen, PP-ASEL, Instrument Airplane
Sacramento, CA

Mark Hansen wrote:

Well, if it's only a problem when an aircraft is on the ILS and it's below
800/2, and given that ATC isn't going to release an IFR departure if an
aircraft is on the ILS, then it doesn't appear to be a problem.

I'm not sure that's the only time it's a problem. It just the minimum
that the tower is required to keep the area clear. I would expect that
ILS can be interfered with regardless of the current weather.

I think the idea is that even a distorted GS will be accurate enough to get
you to within 800/2 of the runway.