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

I fly from KLAX to KLAS, using the FMC to handle most of the flight.
With the routing I put in, the FMC decides on some default altitudes
and includes required altitudes for the arrival and departure
procedures I select. Part of what it does is to create a descent
schedule from the nominal cruise altitude to the arrival procedure.

So I leave KLAX and my last explicit instruction from ATC is "climb
and maintain FL290," which is my programmed and filed cruise altitude.
Now, my question is this: If the FMC has a programmed descent in its
route, do I let the FMC start the descent where it sees fit, or do I
force the aircraft to maintain FL290 until ATC explicitly clears me
for my own navigation or for a lower altitude? And if ATC's last
instruction had simply been "resume own navigation" or "proceed as
filed," would that mean that I'd be free to begin the descent whenever
the FMC (or I) decides it's best?

In situations where I can begin the descent at my discretion (assuming
that own navigation implies this), should I tell ATC that I'm leaving
my cruise altitude? If the FMC has a continuously changing estimate
of lower altitudes in the descent profile, what should I give as my
target altitude? The next fix that has a specific altitude? (Such as
a fix in the arrival procedure)

Climbing I think I understand. If I'm told to resume own navigation,
or cleared as filed in the first place, I climb per my flight plan/FMC
profile. If ATC says maintain X, I stay at X until ATC tells me to
resume own navigation or instructs me to change altitudes. But the
descent part still has me a bit confused.

--
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Mxsmanic wrote:
I fly from KLAX to KLAS, using the FMC to handle most of the flight.
With the routing I put in, the FMC decides on some default altitudes
and includes required altitudes for the arrival and departure
procedures I select. Part of what it does is to create a descent
schedule from the nominal cruise altitude to the arrival procedure.

So I leave KLAX and my last explicit instruction from ATC is "climb
and maintain FL290," which is my programmed and filed cruise altitude.
Now, my question is this: If the FMC has a programmed descent in its
route, do I let the FMC start the descent where it sees fit, or do I
force the aircraft to maintain FL290 until ATC explicitly clears me
for my own navigation or for a lower altitude? And if ATC's last
instruction had simply been "resume own navigation" or "proceed as
filed," would that mean that I'd be free to begin the descent whenever
the FMC (or I) decides it's best?

In situations where I can begin the descent at my discretion (assuming
that own navigation implies this), should I tell ATC that I'm leaving
my cruise altitude? If the FMC has a continuously changing estimate
of lower altitudes in the descent profile, what should I give as my
target altitude? The next fix that has a specific altitude? (Such as
a fix in the arrival procedure)

Climbing I think I understand. If I'm told to resume own navigation,
or cleared as filed in the first place, I climb per my flight plan/FMC
profile. If ATC says maintain X, I stay at X until ATC tells me to
resume own navigation or instructs me to change altitudes. But the
descent part still has me a bit confused.

Are you flying IFR? if so then ATC will tell you what altitude to be at.
Resume own navigation refers to routing not altitude. VFR is a
different set of rules.

i wonder if his simulator's ATC tells him to hang himself he will? (one
can only hope)
John Theune wrote:
Mxsmanic wrote:
I fly from KLAX to KLAS, using the FMC to handle most of the flight.
With the routing I put in, the FMC decides on some default altitudes
and includes required altitudes for the arrival and departure
procedures I select. Part of what it does is to create a descent
schedule from the nominal cruise altitude to the arrival procedure.

So I leave KLAX and my last explicit instruction from ATC is "climb
and maintain FL290," which is my programmed and filed cruise altitude.
Now, my question is this: If the FMC has a programmed descent in its
route, do I let the FMC start the descent where it sees fit, or do I
force the aircraft to maintain FL290 until ATC explicitly clears me
for my own navigation or for a lower altitude? And if ATC's last
instruction had simply been "resume own navigation" or "proceed as
filed," would that mean that I'd be free to begin the descent whenever
the FMC (or I) decides it's best?

In situations where I can begin the descent at my discretion (assuming
that own navigation implies this), should I tell ATC that I'm leaving
my cruise altitude? If the FMC has a continuously changing estimate
of lower altitudes in the descent profile, what should I give as my
target altitude? The next fix that has a specific altitude? (Such as
a fix in the arrival procedure)

Climbing I think I understand. If I'm told to resume own navigation,
or cleared as filed in the first place, I climb per my flight plan/FMC
profile. If ATC says maintain X, I stay at X until ATC tells me to
resume own navigation or instructs me to change altitudes. But the
descent part still has me a bit confused.

Are you flying IFR? if so then ATC will tell you what altitude to be at.
Resume own navigation refers to routing not altitude. VFR is a
different set of rules.

John Theune writes:

Are you flying IFR?

Yes. I've filed a SID, a route, and a STAR, and programmed this into
the FMC as well. The FMC apparently decides when to start the descent
from cruise (if you don't override it), presumably based on the
altitude restrictions it has to respect for the arrival procedure.

if so then ATC will tell you what altitude to be at.
Resume own navigation refers to routing not altitude.

Ah ... is there another phrase that also means altitude is at my
discretion, or is altitude always under the control of ATC? The fact
that the FMC provides for its own descent schedule implies that there
must be situations in IFR where I'm allowed to climb or descend at my
discretion (?).

--
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Mxsmanic,

The fact
that the FMC provides for its own descent schedule implies that there
must be situations in IFR where I'm allowed to climb or descend at my
discretion


No. That fact implies that the simulation does not simulate real life
well in this respect. You wanted an example, you got one all by
yourself.

--
Thomas Borchert (EDDH)

Thomas Borchert writes:

That fact implies that the simulation does not simulate real life
well in this respect.

What part of the FMC or ATC simulation is incorrect?

--
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In a previous article, Mxsmanic said:
if so then ATC will tell you what altitude to be at.
Resume own navigation refers to routing not altitude.

Ah ... is there another phrase that also means altitude is at my
discretion, or is altitude always under the control of ATC? The fact
that the FMC provides for its own descent schedule implies that there
must be situations in IFR where I'm allowed to climb or descend at my
discretion (?).

If your FMC wants to descend, ask ATC for a descent. If you're going to
be descending with multiple segments of different descent rates, ask ATC
for "descent at pilots discretion".

Real world IFR flying is about coordinating your actions with those of all
the other planes out there, not flying along fat, dumb and happy doing
whatever you feel like. That's the whole point of ATC - to make sure you
don't hit what you can't see. ATC's second priority is to make sure the
system runs smoothly, so your actions don't interfere with somebody else
and somebody else's actions don't interfere with you.

--
Paul Tomblin http://blog.xcski.com/
"I love the smell of burning components in the morning.
Smells like victory." (The ******* Operator From Hell)

Paul Tomblin writes:

If your FMC wants to descend, ask ATC for a descent. If you're going to
be descending with multiple segments of different descent rates, ask ATC
for "descent at pilots discretion".

OK, thanks. Is that the procedure followed by pilots in the real
world as well?

Real world IFR flying is about coordinating your actions with those of all
the other planes out there, not flying along fat, dumb and happy doing
whatever you feel like.

Yes. That's why I'm trying to find out what the rules are.

That's the whole point of ATC - to make sure you
don't hit what you can't see. ATC's second priority is to make sure the
system runs smoothly, so your actions don't interfere with somebody else
and somebody else's actions don't interfere with you.

Yes. I try to be cooperative with ATC.

--
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In a previous article, Mxsmanic said:
Paul Tomblin writes:

If your FMC wants to descend, ask ATC for a descent. If you're going to
be descending with multiple segments of different descent rates, ask ATC
for "descent at pilots discretion".

OK, thanks. Is that the procedure followed by pilots in the real
world as well?

I live and fly in the real world, so I can only talk about the real world.
My "real world" is part 91 IFR below the oxygen altitudes, however, so
some of what I say isn't applicablle to part 121 in class A airspace.

Another "trick" is to ask for a cruise clearance, which also allows you to
manage your own descent profile. However in my chunk of the real world,
I've never seen it used or needed it.

I fly with a Garmin 296 handheld GPS. In my experience, nearly always
just around the same time it says I need to start my descent if I want to
descend at 500fpm to my destination, ATC clears me down to a lower
altitude without being asked.

--
Paul Tomblin http://blog.xcski.com/
A male pilot is a confused soul who talks about women when he's flying,
and about flying when he's with a woman.

"John Theune" wrote

Are you flying IFR? if so then ATC will tell you what altitude to be at.
Resume own navigation refers to routing not altitude. VFR is a different
set of rules.

He is flying a simulator "game," so he isn't really flying anything, and has
no consequences to whatever he does.

Get it?
--
Jim in NC