Speed limits on optimized decent profile arrivals

[wheelsup]

Question:

If cleared to "Descend Via" an arrival, and you previously instructed to fly 300 KIAS or greater, and there is a 280 KIAS speed limit on a fix, what speed should you fly?

I choose 300 but the correct answer was 280 apparently. Does anyone have the reference for this? I was under the impression we fly what speed we are assigned unless told "normal speed". Example "descend via the Troops 2 normal speed" vs "Descend via the Troops 2 maintain 300 knots". I have been given "maintain speed xxx" numerous times and upon querying ATC always wants us at that speed and not published speeds on the arrivals. Obviously I always ask but this question/answer is counter intuitive.

Or is it that they must clear you to maintain the speed they wish while clearing for the ODP, if you were given a previous assignment that goes out the window unless they give it to you again when clearing you to descend on the arrival?

 

[Bernoulli Fan]

The best part about your question is that few controllers know either, but half of them will aggressively adopt one side of the issue, and half the other side. Their arguments will be sporadically shouted across the control room in between curt responses to pilots checking in on frequency, although the issue at hand will soon be forgotten as the argument devolves into whether In-N-Out Burger is the greatest hamburger joint, the relative merits of pit bulls as pet canines, and what does it TAKE to get a break around here anyway?

 

[ross9238]

I thought once they clear you with descend via the arrival, the previous instructions are not valid anymore.

Edit:
I just checked under the FAA docs and the N7110.584 document talks about the climb via and descend via procedures. It does not say anything about speed restrictions assigned vs speeds on the arrival.

I just figured at that point they would want me to follow the speeds published on the arrival.

 

[RobertB]

If another speed is not stated with the descend via clearance, you are expected to comply with the speed on the plate.

Example: If you are assigned 310 knots and I say descend via the xxx arrival, you are expected to comply with the listed speed.

If I want you to still maintain 310 knots ( which is different than what is published) then I must restate it with the descend via clearance. "Descend via the xxx arrival except maintain 310 knots" or something like that.

 

[wheelsup]

If another speed is not stated with the descend via clearance, you are expected to comply with the speed on the plate.

Example: If you are assigned 310 knots and I say descend via the xxx arrival, you are expected to comply with the listed speed.

If I want you to still maintain 310 knots ( which is different than what is published) then I must restate it with the descend via clearance. "Descend via the xxx arrival except maintain 310 knots" or something like that.

OK thanks!

 

[genot]

what does it TAKE to get a break around here anyway?

On the weekends just saying I think I had a deal works well. When they kick you out, tell them you must file at ATSAP immediately. Surf the web for a while and then go back and say, I completely forgot I had altitude. You've got close to an hour before they can get someone in to check. I'm mostly joking.

 

[spades9048]

I don't deal with any OPD's that have speed restrictions. However, there are other areas at my center that do and I have had to attend briefings on it. At ZME, we have been told that if you have been assigned a speed and we want you to continue to maintain that speed then we would need to say, "Descend via the XXX arrival, landing XXX...except maintain 300 knots" otherwise we should expect pilots to comply with all restrictions on the arrival.