Confusion about when it's my navigation, and when it's ATC

Capt.Doug writes:

The profile in the FMS is for efficiency and does not take other traffic
into account. You must wait until ATC explicitely clears you to another
altitude.

So it would probably be best to set the MCP to prevent any descent
until I'm cleared, then?

If you are about to pass the FMS's descent point, politely prompt
ATC for a lower altitude.

"Request descent," or something, I presume.

Going into LAS, you very well may get vectors off
the planned route so that ATC can adequately space the arrival traffic (in
the real world).

In simulation, too, even though traffic is sometimes too light to
justify it (the ATCs need practice as well). In fact, it seems that I
almost never follow the arrival procedure as published. Often just as
I'm beginning it, ATC gives me other instructions. I suppose it's a
bit of a relief as then all I have to do is follow their instructions,
rather than try to follow the arrival chart (but if the FMC is doing
it, it's easy).

No. That would be for lateral navigation only unless explicitely cleared for
different altitudes.

Is there a specific phrasing that means "you can do your own lateral
AND vertical navigation"? Or does ATC as a rule never let IFR flights
select their own altitudes?

Here is an example that one of my colleagues recently
received counseling about. He was cleared via the KORRY 3 arrival into KLGA.
He started to descend according to the profile. ATC asked why he was
descending and to call a number after landing (not good). He was cleared via
the KORRY 3, not cleared to descend via the KORRY 3. Slight difference, but
very important for traffic seperation.

Hmm. I just assumed that since the plates usually indicate altitudes,
"cleared via the KORRY 3" would necessarily mean following both the
course and altitude indications. What does ATC say if they want you
to follow everything on the plate, including the indicated altitudes?

Did your colleague get into significant trouble?

Yes, the Aeronautical Information Manual states that a pilot should advise
when leaving an altitude.

OK.

Yes.

OK, so should I say something like "leaving FL290 for 12000 at CLARR,"
assuming I'm already cleared to descend at my discretion?

Query ATC for the assigned altitude so that both of you are on the same
page. Climbs are the same as descents. 'resume own navigation' is for
lateral flight. Don't climb unless expicitely assigned a new altitude by
ATC.

So there is no equivalent of "resume own navigation" for altitude,
like "resume own altitude," or whatever?

If ATC regularly overrides the plates and (apparently) doesn't often
clear anyone to follow the altitude indications on the plates, why do
all the approach plates seem to mention altitudes? Just for radio
loss? (Except they often seem to have separate procedures for
communications loss.)

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"Mxsmanic" wrote in message
So it would probably be best to set the MCP to prevent any descent
until I'm cleared, then?

MCP = max continuous power? Sorry- not familiar with the term as used on an
FMS. The important thing is to not set the altitude hold for descent until
cleared by ATC.

In simulation, too, even though traffic is sometimes too light to
justify it (the ATCs need practice as well). In fact, it seems that I
almost never follow the arrival procedure as published. Often just as
I'm beginning it, ATC gives me other instructions. I suppose it's a
bit of a relief as then all I have to do is follow their instructions,
rather than try to follow the arrival chart (but if the FMC is doing
it, it's easy).

A good center controller will have all of the arrivals spaced like pearls
before everyone hits the arrival's gate. That way everyone can follow the
arrival as charted with ATC isssuing speed changes to maintain spacing.

Is there a specific phrasing that means "you can do your own lateral
AND vertical navigation"? Or does ATC as a rule never let IFR flights
select their own altitudes?

The most common is a clearance to cross a fix at an assigned altitude
(crossing restriction). Say for example you are cruising at FL290 and the
controller isues you a clearance to cross a fix at 12000'. It is your
perogative as to when to start your descent so long as you cross the fix at
the assigned altitude.

During the climb, ATC sees the final altitude we requested on our flight
plan. They try to get us up there, traffic permitting. After that we request
from ATC any altitude changes we want and they work us to that altitude,
traffic permitting.

What does ATC say if they want you
to follow everything on the plate, including the indicated altitudes?

"DESCEND via the Korry 3"

Did your colleague get into significant trouble?

No, because seperation wasn't lost.

OK, so should I say something like "leaving FL290 for 12000 at CLARR,"
assuming I'm already cleared to descend at my discretion?

Sounds professional.

So there is no equivalent of "resume own navigation" for altitude,
like "resume own altitude," or whatever?

In the IFR world, altitude is all important. There are crossing restrictions
and block altitudes, but most of the time we follow

If ATC regularly overrides the plates and (apparently) doesn't often
clear anyone to follow the altitude indications on the plates, why do
all the approach plates seem to mention altitudes? Just for radio
loss?

In the real world we usually follow the arrival procedures with the
altitudes as published. When flying the big jets, just remember that you
will need 3 miles for every 1000' you want to descend plus another 5 miles
to slow for the 250 knot speed restriction at 10000'.

D.

Capt.Doug,

OK, so should I say something like "leaving FL290 for 12000 at CLARR,"
assuming I'm already cleared to descend at my discretion?

Sounds professional.


Actually, no, it doesn't. The word "for" is to be avoided because it sound
the same as "four". It sounds like many airline pilots (just like "twelve
hundred" or "with you"), but professional it is not.

--
Thomas Borchert (EDDH)

Thomas Borchert writes:

Actually, no, it doesn't. The word "for" is to be avoided because it sound
the same as "four". It sounds like many airline pilots (just like "twelve
hundred" or "with you"), but professional it is not.

Which airline do you fly for, again?

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Mxsmanic,

Which airline do you fly for, again?


Are you determined to make a complete idiot of yourself now? But I'm
glad to see it is possible to penetrate that armor you've conveniently
constructed around your sorry self.

GA aircraft and airlines use the same radio frequencies. They are
required to use the same phrases in their radio work. So I don't need
to fly for an airline to make qualified statements about radio work. I
have been educated in radio work in just the same way as an airline
pilot. You haven't. So take the advice of another poster: STFU and take
notes!

FWIW, the part I mentioned is easily obtainable by reading the AIM or
the Pilot-Controller-Glossary, which you have been pointed to, but are
too lazy to read. Instead, you prefer to try making silly personal
attacks. You're a lying troll.

--
Thomas Borchert (EDDH)

Thomas Borchert wrote:

Mxsmanic,


Which airline do you fly for, again?



Are you determined to make a complete idiot of yourself now? But I'm
glad to see it is possible to penetrate that armor you've conveniently
constructed around your sorry self.

Well stated, Tom.

I fell for this jerk in the beginning.

"Thomas Borchert" wrote in message
Actually, no, it doesn't. The word "for" is to be avoided because it sound
the same as "four". It sounds like many airline pilots (just like "twelve
hundred" or "with you"), but professional it is not.

Let's split hairs- I am aware of the Flying Tigers' accident. However,
'four' followed by 'twelve' is hard to confuse. 'four one two thousand'
doesn't make sense either. Professionals are admonished to be concise and
efficient in their transmissions. In that sense, and because Maniac did say
that he was already issued the crossing restriction, "Leaving FL290" would
be better.

D.

Capt.Doug writes:

MCP = max continuous power?

Mode Control Panel--the gadgets on the glare shield that control the
autopilot. So I set the ALT HOLD parameter on that to prevent the FMS
from going below a certain altitude on its own.

The important thing is to not set the altitude hold for descent until
cleared by ATC.

Up to now, I've been setting the altitude above my cruise for the
climb, and then below the airfield for my descent, thus preventing it
from ever limiting the FMS. But it now appears that I should be using
it to make sure I don't overstep any ATC instructions. So if they say
climb and maintain 5000, I set 5000 until I get new instructions, thus
preventing the FMS from taking me all the way to cruise altitude
before I've been cleared for it.

I note, however, that I'm often cleared for a higher altitude before
reaching the previously cleared altitude, so sometimes I just keep a
hand near the altitude setting on the MCP, ready to adjust it if I
have to, while letting the FMC do its thing.

A good center controller will have all of the arrivals spaced like pearls
before everyone hits the arrival's gate.

The quality of controllers in simulation is quite variable, but the
good ones are just as good as real controllers (sometimes they _are_
real controllers, who, for some reason, like to simulate their work
when they aren't doing it for real--I guess some people really like
their jobs).

The most common is a clearance to cross a fix at an assigned altitude
(crossing restriction). Say for example you are cruising at FL290 and the
controller isues you a clearance to cross a fix at 12000'. It is your
perogative as to when to start your descent so long as you cross the fix at
the assigned altitude.

OK, I've had those. I'll remember to treat them as an implicit
clearance to descend or climb to the specified altitude at my
discretion.

During the climb, ATC sees the final altitude we requested on our flight
plan. They try to get us up there, traffic permitting. After that we request
from ATC any altitude changes we want and they work us to that altitude,
traffic permitting.

Do you often need a different altitude from the one you filed?
Perhaps for fuel considerations, or headwinds, or something?

"DESCEND via the Korry 3"

Ah ... see, I would have interpreted that as more restrictive, i.e.,
meaning that I should change altitudes but that my heading should not
change. I guess it's the other way around. And I suppose it doesn't
make much sense that you'd be cleared to descend via the STAR and yet
not be cleared to follow it laterally, now that I think more about it.

No, because seperation wasn't lost.

So what do they say in this telephone call?

Sounds professional.

Cool. Now if I can just say it with a Texas drawl.

In the IFR world, altitude is all important. There are crossing restrictions
and block altitudes, but most of the time we follow

I would have thought that altitude and track would both be about
equally important.

In the real world we usually follow the arrival procedures with the
altitudes as published. When flying the big jets, just remember that you
will need 3 miles for every 1000' you want to descend plus another 5 miles
to slow for the 250 knot speed restriction at 10000'.

I have discovered that it's much harder to move large jets towards the
ground than it is to move them towards the sky.

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"Mxsmanic" wrote in message Do you often need a different altitude from
the one you filed?
Perhaps for fuel considerations, or headwinds, or something?

Often times our actual weight will be slightly different from the flight
planned weight requiring 2000' up or down for fuel optimization. Turbulence
is another reason to change altitudes, sometimes 10000' or more. A 2000'
change in altitude usually doesn't make enough difference in headwinds to
justify the increased fuel burn of changing altitudes. Sometimes we are just
plain stuck at an inefficient altitude because of same direction traffic.

So what do they say in this telephone call?

Along the lines of 'Now you know- don't do it again".

I would have thought that altitude and track would both be about
equally important.

They are both important, however altitude leeway is +/-300' whereas airways
have .5 to 4 miles of leeway.

D.

Capt.Doug writes:

They are both important, however altitude leeway is +/-300' whereas airways
have .5 to 4 miles of leeway.

Three hundred feet seems generous for altitudes. I thought I read
somewhere that I was supposed to be within 100 feet, or was it 60
feet? Now I can't seem to find a specific tolerance in the FARs. Of
course this isn't normally a problem if I'm on autopilot, but when
flying by hand I still have trouble holding an altitude.

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