ILS critical area when the tower is closed?

On 11/20/2005 2:54 PM, Bob Gardner wrote:

AIM Figure 2-3-16?

Sorry I wasn't clear, Bob. I wasn't asking where the hold short
or ILS markings were or how they were depicted at the airport.


If there are taxiway markings for an ILS critical area,
and the departing pilot knows that the weather is even close to 800-2, s/he
doesn't have to depend on a controller for instructions. The controlling
authority (in the absence of a controller) knows what the situation with
regards to inbounds is and can advise the departing pilot if there is
someone on the way in. "Hold short of runway 16, traffic on two mile final."

Just who is going to say "Hold short" when the tower is closed?

Perhaps the only time you have to worry about the ILS critical area
is when the weather is below 800/2, in which case only IFR departures
will be of concern, and they won't get their clearance unless the
airspace is clear.

Assuming the weather is above VFR minimums, VFR arrivals and departures
could interfere with the ILS system, and there appears to be no protocol
to prevent that, since any airplane using the system isn't depending on it
to get to minimums anyway?

Well, I guess I have my answer.


Bob Gardner

"Mark Hansen" wrote in message
...
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, PP-ASEL, Instrument Airplane
Sacramento, CA

Good point about the 'hold short' transmission. Brain fart.

Seems to me that at one point you wondered how a pilot was expected to know
that there was an ILS critical area without being told by the tower...that
is why I referred to the taxiway markings.

Bob

"Mark Hansen" wrote in message
...
On 11/20/2005 2:54 PM, Bob Gardner wrote:

AIM Figure 2-3-16?

Sorry I wasn't clear, Bob. I wasn't asking where the hold short
or ILS markings were or how they were depicted at the airport.


If there are taxiway markings for an ILS critical
area,
and the departing pilot knows that the weather is even close to 800-2,
s/he doesn't have to depend on a controller for instructions. The
controlling authority (in the absence of a controller) knows what the
situation with regards to inbounds is and can advise the departing pilot
if there is someone on the way in. "Hold short of runway 16, traffic on
two mile final."

Just who is going to say "Hold short" when the tower is closed?

Perhaps the only time you have to worry about the ILS critical area
is when the weather is below 800/2, in which case only IFR departures
will be of concern, and they won't get their clearance unless the
airspace is clear.

Assuming the weather is above VFR minimums, VFR arrivals and departures
could interfere with the ILS system, and there appears to be no protocol
to prevent that, since any airplane using the system isn't depending on it
to get to minimums anyway?

Well, I guess I have my answer.


Bob Gardner

"Mark Hansen" wrote in message
...
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, PP-ASEL, Instrument Airplane
Sacramento, CA

On 11/20/2005 5:51 PM, Bob Gardner wrote:

Good point about the 'hold short' transmission. Brain fart.

Seems to me that at one point you wondered how a pilot was expected to know
that there was an ILS critical area without being told by the tower...that
is why I referred to the taxiway markings.

No, I was asking how the pilot would know to hold clear of the ILS
critical area, not where it was located on the airport.

But anyway, I think I have my answer. Thanks for your help.


Bob

"Mark Hansen" wrote in message
...
On 11/20/2005 2:54 PM, Bob Gardner wrote:

AIM Figure 2-3-16?

Sorry I wasn't clear, Bob. I wasn't asking where the hold short
or ILS markings were or how they were depicted at the airport.


If there are taxiway markings for an ILS critical
area,
and the departing pilot knows that the weather is even close to 800-2,
s/he doesn't have to depend on a controller for instructions. The
controlling authority (in the absence of a controller) knows what the
situation with regards to inbounds is and can advise the departing pilot
if there is someone on the way in. "Hold short of runway 16, traffic on
two mile final."

Just who is going to say "Hold short" when the tower is closed?

Perhaps the only time you have to worry about the ILS critical area
is when the weather is below 800/2, in which case only IFR departures
will be of concern, and they won't get their clearance unless the
airspace is clear.

Assuming the weather is above VFR minimums, VFR arrivals and departures
could interfere with the ILS system, and there appears to be no protocol
to prevent that, since any airplane using the system isn't depending on it
to get to minimums anyway?

Well, I guess I have my answer.


Bob Gardner

"Mark Hansen" wrote in message
...
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, PP-ASEL, Instrument Airplane
Sacramento, CA




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

the weather is below 800/2, in which case only IFR departures
will be of concern

People may be taxiing around the airport with no intention of taking
off, for example, to fuel up, to do maintanance, or to more the aircraft.

I suppose such an aircraft could call departure first, to ensure that
such operation will not interfere with anybody on approach.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.

"Jose" wrote in message
. ..

People may be taxiing around the airport with no intention of taking off,
for example, to fuel up, to do maintanance, or to more the aircraft.


With all that activity it's a wonder the tower is closed.

People may be taxiing around the airport with no intention of taking off,
for example, to fuel up, to do maintanance, or to more the aircraft.
With all that activity it's a wonder the tower is closed.

One aircraft is sufficient.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.

"Jose" wrote in message
. ..

One aircraft is sufficient.


It's typically not enough to keep the fuel vendor open.

In article ,
Jose wrote:

People may be taxiing around the airport with no intention of taking off,
for example, to fuel up, to do maintanance, or to more the aircraft.
With all that activity it's a wonder the tower is closed.

One aircraft is sufficient.

Jose

Doesn't even have to be an aircraft. A car or truck would disrupt the
signal too. Some uncontrolled airports have some pretty strange stuff
going on.

On 11/20/2005 6:38 PM, Jose wrote:

the weather is below 800/2, in which case only IFR departures
will be of concern

People may be taxiing around the airport with no intention of taking
off, for example, to fuel up, to do maintanance, or to more the aircraft.

I suppose such an aircraft could call departure first, to ensure that
such operation will not interfere with anybody on approach.

Jose

With weather below 800/2, the only people in the vicinity of the
ILS critical area would be IFR departures, right? I can't think
of any reason to be taxiing to the departure end of a runway unless
you're taking off (or just landed). In either case, the flight would
be IFR due to the weather.

I was really thinking more of the case during VFR conditions where
the ILS system is being used more for practice. I think the bottom
line is, if you're using an ILS during VFR conditions, you should
expect some interference in the signal whether or not the tower is
in operation - since even if it is in operation, it doesn't have to
keep the ILS critical area clear unless weather is below 800/2.

Thanks,


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

With weather below 800/2, the only people in the vicinity of the
ILS critical area would be IFR departures, right?

I don't know. Therefore I wouldn't count on it. I suspect it depends
on the specific geography of the airport.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.