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

Jim Carter wrote:
He'd reboot - its Windows and Flightsim after all.

I just read about a guy who's Garmin mx20 died.

The screen went blank and then blue.

On the bottom of the screen:

"Microsoft Service Pack 2"

ak.

Just out of curiosity, what simulator are you using?

Gus
EGYC

"Mxsmanic" wrote in message
news
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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Morgans writes:

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

The consequences are slightly different; IFR flight, however, is the
same, with the same rules and procedures, with a few very minor
exceptions imposed by technical constraints (not applicable in the
context of this discussion).

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Pixel Dent writes:

Well, once again I don't know much about airliners, but in smaller
planes at least you don't generally increase airspeed to descend you
reduce power.

The FMC does this through the autothrottle. At least the one I use
lets you choose between a descent path (altitudes respected, ignoring
speed constraints if necessary) and a speed path (speeds respected,
even if altitudes must be ignored), with the former being the default.
At least that's what I understand of it thus far.

Anyway, the FMC normally controls lateral and vertical navigation and
the throttle, and optimizes all in order to attain its preprogrammed
path, altitude, and speed.

At least in the area of the country I fly ATC often has
speed restrictions on the airliners so they couldn't increase speed
during a descent if they wanted to. It's good practice to hold your
airspeed steady while reducing power to make your descent.

The FMC tries to do this, although altitude and course are normally
the priorities. It does a good job in most cases.

In the world of simulation, we rarely have heavy traffic, so I only
occasionally get speed restrictions. They are not too hard to
respect, usually--just setting a different speed in the FMC is often
sufficient.

Practice, practice, practice. Everyone has a hard time understanding at
first but the more you listen the more it makes sense.

Probably, but it seems so easy to misunderstand that I should think it
would be very mistake prone. I read back almost every instruction I
get to ATC just to make sure that I've understood it.

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Mxsmanic,

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

The consequences are slightly different; IFR flight, however, is the
same, with the same rules and procedures, with a few very minor
exceptions imposed by technical constraints


How would you know? Many here can make a direct comparison - and have. You can't.

--
Thomas Borchert (EDDH)

A Guy Called Tyketto writes:

I just told you. LOOP4, KEPEC1, ILS 25L at KLAS. Those are also
charts.

I have those.

You should look at those, because if you choose the wrong
chart, and your equipment can't support the chart you're filing, you'll
be given another SID/STAR to use.

On the 737, I have essentially everything. I usually check for
specific instructions or restrictions on the type of aircraft.

If you lost your FMC, what would you do?

I would use the MCP alone. If that fails, I fly the aircraft by hand,
which I can do, although it's rather tedious over long distances.

I do have a problem with transitions between automated systems and
flying by hand. Sometimes it's hard for me to keep track of what the
systems are doing and what I am doing. As a last recort I
occasionally disengage the automation entirely and fly by hand
(particularly for approaches and landings), but that is not the
objective, that's just to get on the ground safely.

You just can't let your instruments do everything for you
the moment you rotate.

You can if they work as designed. And real life comes very close to
that, although I understand most pilots fly the first part of the
departure by hand, and often landings as well.

I'd fathom to see what would happen if you were a /A and didn't have an
FMC.

I don't know what /A is, but if I don't have a FMC, I fly with
autopilot alone. If I don't have that, I fly by hand. However, I
would not want to fly an aircraft without at least an autopilot, if I
were planning anything other than practice in the pattern.

I doubt it. There's two places where the Center controller
could give you the crossing restriction; one at MISEN, the other at
CLARR. If he gave you the one at MISEN (which I know he did), it would
make the CLARR crossing restriction a lot easier to make.

I don't recall MISEN, but I recall the CLARR restriction. He said
cross CLARR at 12000 or whatever, and I was at FL290, and so I assumed
that my descent to CLARR was implied in this--otherwise how could I
follow the instructions. So when the FMC started down, I didn't say
anything, as I recall.

They had visual approaches in use.

Yes. Visual approaches seem to be popular when weather permits. I
still tune the ILS and follow it, if possible.

Also, it has been said befo 99.9% of all landings are hand
flown, not autolanding, unless on a Cat III ILS approach. ILS 25L
is not CATIII.

The aircraft will still autoland on it.

It could be because visual approaches may be in use over using
an instrument approach.

No doubt, although ATCs in simulation seem to enjoy making more work
for themselves, rather than less (in contrast to the real world).

It provides more flexibility with ATC, plus puts separation
responsibility back on the pilot.

That is probably the main motivation in real life. Simulation ATCs
just like to have more practice, understandably.

If you were following traffic, and you were coming in too fast
and had to go around, that may not be ATC's fault. There would
be some things you could have done to slow your speed down.

When he first called the traffic, it was at 11:00. By the time I saw
it, it was around 8:00 and moving fast opposite to my track. When I
called the traffic in sight, he told me to follow it, which required a
steep 180 to get behind him. As I was still in LNAV and was fooling
with the FMC and MCP trying to figure out why it had refused the
descent path for my approach, I got confused and had trouble turning
to follow the traffic. I was all over the place on the approach and
way too close to the other traffic (which had not yet touched down,
and I was only at 1500 feet or so and nearly abeam the threshold), and
finally I decided to go around--which was an adventure in itself since
I had not previously tried to go around with an FMC and fancy
autopilot in the mix. I disconnected everything and flew by hand to a
few thousand feet, and ATC vectored me around, which was troublesome
because the VOR he wanted was on my MFD but not tuned, so I had to try
to find it on the MFD and steer towards it. I finally stabilized and
there was another aircraft on the way in and I was told to find it and
follow it as before. This time I was much further out, however, and I
was able to line up better. Once I was nearly on the centerline I set
up the MCP for the ILS again, and then I set for autoland just to get
some rest. The landing proceeded uneventfully on 25R, I think.

I don't know if the ATC screwed up; he was a regular controller, not a
student. I certainly made a mess of it, though. It's good that I had
the seat belt sign on. I need to practice more with dealing with the
unexpected while using an FMC and/or autopilot.

This is all much easier when I fly the Baron, as the autopilot isn't
terribly fancy and there's no FMC, so I'm already on top of things
when ATC calls. But I've screwed up in that as well, in one case
trying to land on the wrong runway until I heard Approach telling
other people about a plane that didn't seem to know where it was
going, hint hint.

I haven't had any crashes, though, except in extremely strong winds
(near Denver, once at KVGT in incredibly gusty winds, etc.). I
haven't had a fatal crash in a long time. The last one was when I hit
a hill on the way out of Henderson Executive at night. I still don't
know which hill it was, as I had examined the chart carefully and was
sure that my departure was clear of terrain. But it was dark.

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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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Gus Cabre writes:

Just out of curiosity, what simulator are you using?

Microsoft Flight Simulator 2004.

However, I use the PMDG 737-800 add-on aircraft, which is equipped
like the real thing (practically a different world as compared to the
default 737 in the simulator). I also use the Dreamfleet Baron 58
add-on, which, again, is also in a category of its own. Both are
renowned for their uncompromising realism with respect to the real
aircraft.

I also have a separate joystick and throttle, and rudder pedals.
Anything fancier is hard to justify at this time.

I fly a mixture of VFR and IFR on the Baron, and mostly IFR on the
737. I also use VATSIM, the leading virtual flight network, so that I
can interact with other human pilots and controllers by radio, rather
than just interact with the computer-generated stuff provided by MSFS
when it is in offline mode.

All in all, the realism is striking, and much better than some
detractors like to believe.

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Mxsmanic wrote in
:

All in all, the realism is striking, and much better than some
detractors like to believe.

How do you know?

Mxsmanic,

Also, it has been said befo 99.9% of all landings are hand
flown, not autolanding, unless on a Cat III ILS approach. ILS 25L
is not CATIII.

The aircraft will still autoland on it.


But t odo that would be totally unrealistic. You can't have it both
ways: Either you strive for attempting maximum realism, or you fudge.

--
Thomas Borchert (EDDH)