wrote in message news:Sjwgf.4659$pF.917@fed1read04...
KP wrote:

Man, I hate to side with McNicholl but...

wrote in message news:cjlgf.4216$pF.687@fed1read04...

Steven P. McNicoll wrote:

wrote in message
news:CX9gf.1261$pF.1153@fed1read04...


It's a problem during a coupled approach especially if the pilot is
planning to do an autoland.



It's not a problem if the weather is good.



Not so, Steve. It can cause control problems and certainly adversely
affect an autoland. That is why your handbook contains a caveat about
such approaches.

Approach couplers and autoland systems are weather independent.~


The only "caveat" in the .65 regarding coupled or autoland ILS approaches
is in 3-7-5b. This simply requires an advisory to aircraft of "ILS/MLS
CRITICAL AREA NOT PROTECTED" when the weather is at or above 800-2.

So, if the weather is good (or good enough) all the pilot executing a
coupled or autoland gets is a warning (ie, a reminder not to trust the
electrons too much). For all practical purposes the ILS critical areas
are not in play. Nobody gets held at the instrument hold lines. In
other words, it's not a problem if the weather is good.

You're a bit out of context.

I don't think I am.

Here is the context:
b. Air carriers commonly conduct "coupled" or "autoland" operations to
satisfy maintenance, training, or reliability program requirements.
Promptly issue an advisory if the critical area will not be protected when
an arriving aircraft advises that a "coupled," "CATIII," "autoland," or
similar type approach will be conducted and the weather is reported
ceiling of 800 feet or more, and the visibility is 2 miles or more.

If you're reading that to mean that unless the advisory is issued the
critical areas are protected you're not only out of context you don't know
controllers or how the ATC system works.

When the weather is good, the crew is required to advise the tower when
they intend to do an autoland or even a non-autoland coupled approach. If
the advisory you mentioned is NOT issued then the crew is trained to
expect that the tower is protecting the critical areas.

Controllers are not going to protect the critical areas (ie, tie up useable
taxiway space and slow down traffic) unless they have a specific foreseeable
requirement to do so (ie, weather below 800-2). They certainly aren't going
to do it on the off-chance some air carrier *might* advise it is doing a
coupled or autoland approach.

If the weather is above 800-2 (ie, good) and ATC is not protecting the
critical areas (which they will not be), then they are required to issue the
advisory when the aircraft tells them it will be making a "coupled" or
"autoland" approach. If they're not issuing the advisory under those
conditions it's because they forgot.

I can't help what crews may or may not be trained to do or expect. If
they're taught to assume that absent an advisory the ILS critical areas are
protected when the weather is above 800-2 they're being taught to make an
unrealistic and potentially dangerous assumption.

The language used to be stronger, in that ATC was required to protect the
critical areas when the crew made such an announcement in good weather.
Apparently, that was too burdensome.

There hasn't been any requirement to protect the critical areas for coupled
or autoland approaches or any other reason when the weather was above 800-2
for the last 27 years or more.

If there ever was (which I doubt) it was very short-lived. Apart from the
sheer physical impracticality of such a requirement, I seriously doubt even
the FAA would put in place a requirement that would delay or otherwise screw
other users of the system in order for some air carrier to fill one of their
internal proficiency/equipment check squares.

Nonetheless, most of the time when the crew announces its intent to do an
autoland/coupled approach in good weather, the tower does not issue that
alert, thus the crew can expect the ILS to perform without interference.

Assuming the tower is protecting the ILS critical areas when the weather is
above 800-2 simply because no advisory is issued is an unrealistic and
potentially dangerous assumption on the part of the aircrew. The smarter,
safer, and more likely assumption would be the tower forgot to issue the
advisory.

De-creeping the thread a bit: the thread is about an airport without a
tower or a closed tower. A savvy air carrier crew would give serious
pause to considering a good-weather autoland at such an airport.

As you're the one who brought the .65 (ie, controllers, their duty
requirements, and thus a situation where the tower is open) into the thread
it's only fair you should be the one to de-creep it.

And when the tower *is* open that aircrew would be equally savvy not to
assume the critical areas are protected simply because ATC forgot to issue
an advisory.