duece12345

I have searched high and low, and have found conflicting answers.

When On an arrival, and you are just cleared (not descending via), are you expected to comply with the speeds on the arrival if no other guidance is given? I am a dirty prop guy that rarely has to deal with this, but it is still good to know.

Thanks

captain152

If it says:
"expect to cross at 12,000
Maintain 250kts"

The altitude must be assigned, "descend via the arrival" or "cross ___ at 12,000"

The speed is mandatory.

Hope this helps

Canada is a whole different ball game

duece12345

So the speed is always mandatory regardless of "cleared xxx arrival" or "descend via xxx arrival". Ok got it thanks.

Now this expect altitude stuff. I was under the impression that even if you got a descend via Clearance, the "expect to cross BALLS at xxx" would not apply unless ATC specificity tells you to "cross BALLS at xxx". The expect is just for planning purposes. Am I out to lunch?

And who the hell came up with this stuff? Damn that man.

usmc-sgt

Speed is not always mandatory, only when it says AT 250 kts. The speed is not mandatory if it simply says EXPECT 250 knots.

Your clearance would sound like this to require the speed where it said EXPECT.
"Airline XYZ, descend via the APC 1 arrival, runway 10 transition. Cross FIXXX at 11 thousand, speed 250 knots."


As for when the altitudes say expect after you are cleared for the arrival, without looking at a chart I would not honor them. I would simply honor all of the "cross AT" notations. As a side note, usually if you are making all of the hard altitude restrictions you will typically be hitting the "expects" as well along the way.

duece12345

That clears it up, thanks sarge.

captain152

USMC said what I was trying to get across far better than I did.

Thanks man

Hope this clears it up for you.

ghogue

In regards to STAR's with "expect to cross" altitude notes, this is from the 7110.65T:

4-5-7. ALTITUDE INFORMATION

Issue altitude instructions as follows: ..................

h. Instructions to vertically navigate on a STAR/RNAV STAR/FMSP with published restrictions. ...............

2. A descend via clearance must not be used where procedures contain published “expect” altitude restrictions.

However, I can remember on at least one occasion I was given such a clearance.

Poppy

If you are cleared for an arrival, then you must maintain the track, and hard speeds. Expect speeds are just for planning purposes except for NRDO. Except for NRDO, or Cleared Via, you would not descend without a specific clearance.

Mostly for planning purposes. The FMCs will plan a descent to arrive at the threshold at TZE. This leaves us crossing arrival gates often thousand of feet higher than what ATC wants. Also, it is fairly hard to achieve much more than a 4 degree descent in many jets. So, we need to know sooner rather than later than we need to cross XXX at 10,000 rather than the 18,000 or even 24,500 that the FMC wants.

With a hard speed at some point on the arrival, ATC knows that it can bring aircraft into that fix with 10 miles in trail, and that will compress to the required 5 miles in trail as the leading aircraft slows before the following aircraft. BTW, the 10 and 5 miles are for example only; I have no idea what ATC actually uses.

NRDO: Remember MEA and AVEF. Without the "Expect to cross at 10,000" or whatever, in the unlikely event of NRDO, a turbojet would be required to enter a hold at the IAF and descend from cruise altitude to the Initial Altitude. This would really skew all of the fuel calculations, AND wreak havoc with the ATC system.

BTW, ATC has started doing "Operation Raincheck" again, and I was lucky enough to participate in one recently. After "working" a bunch of aircraft on their simulator, I gained a new respect for what they do!

Senior Skipper

That's what you're supposed to do. Don't know if I'd end up doing that.

ToastAir

Maybe the attached will clear up some issues and make others clear as mud.

https://docs.google.com/viewer?a=v&p...Hh3-hcaucAWt1A