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About ALT and SPD Restrictions Over IAF

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About ALT and SPD Restrictions Over IAF

Old 18th Apr 2022, 02:36
  #1 (permalink)  
Thread Starter
Join Date: Feb 2021
Location: Taipei
Posts: 9
About ALT and SPD Restrictions Over IAF

Hello everyone!

I have a question for ATC controllers (but pilots please feel free to comment your ideas!)

The situation the other day was a flight into AMS on the NORKU2A STAR plate#10-2 (it was what we filed in the flight plan).

ATC cleared us to direct NORKU (FL280BFL200A on the chart) and explicitly told us to descend FL230 cross below FL280.

Then, before reaching NORKU, ATC cleared us to direct ARTIP (MAX250kts, FL100BFL070A or as instructed by ATC on the chart), descend FL110 and to maintain speed 300kts or greater (nothing about any ALT restrictions over ARTIP).

Two questions: ATC obviously wants us to fly fast as there was pretty much no traffic, but do the ALT and/or SPD restrictions at ARTIP still apply in this case?

When we were pretty close to ARTIP then ATC give us speed 250kts and descend FL070 but as we were close it would’ve taken probably full speedbrake to comply with restrictions (so I just reduce speed and crossed ARTIP around FL105).

Looking back I’m thinking I should have told ATC unable to comply ALT over ARTIP as my interpretation of the phrase “or as instructed by ATC” regarding the ALT should be if ATC tell us something different; in other words if ATC don’t tell us anything then the restrictions should apply.

Please if any ATC controllers or pilots here can shed some light into this situation, many thanks in advance!


Kevingee21 is offline  
Old 18th Apr 2022, 04:02
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Join Date: Sep 2017
Location: Middle East
Posts: 69
Direct routings result in the automatic/by default cancellation of any charted altitude restrictions. Very occasionally they will ask you to cross abeam a certain position at a certain altitude. As always, it's good airmanship to check your radar vectoring charts to ensure the clearance is safe with respect to terrain. Speeds I'm not sure about but am going to guess the same rule applies.
RudderTrimZero is offline  
Old 18th Apr 2022, 04:06
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Join Date: Jun 2005
Location: Brisbane
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The instruction "speed 250kts and descend FL070" you received doesn't stipulate that it applies at ARTIP therefore it is not a requirement to be at ARTIP at 250k and FL070. It's not an uncommon type of instruction and experience over many years has proven that for everyone who says "but the requirement is implied", there are an equal number who say not. If in doubt or you just want clarification then just ask, I do. Occasionally I get a comment from a checker when they are along for the ride and once again 50/50 chance the checker will go quiet when the reply I get from ATC is the opposite of what the checker was expecting so don't feel pressured to one way of thinking just because they are onboard.
BalusKaptan is offline  
Old 18th Apr 2022, 07:52
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Join Date: Sep 2017
Location: Middle East
Posts: 69
There is a document possibly by ICAO, Eurocontrol or the UK CAA that explicitly says what I outlined above. If someone can help identify the source that would be great. The 50% who believe the altitudes must be respected need to understand one thing. The point of an altitude restriction is to ensure clearance from terrain or traffic on other routes. If you are not on such a route, then clearly those exact limitations do not apply. And what exactly is the answer then? To guess or eyeball the level restriction each time? That would leave a lot of room for interpretation which isn't how we fly. I believe such pilots generally hail from from Asia or Latin America where I will admit, local rules could be different because the ATC isn't standard.
RudderTrimZero is offline  
Old 18th Apr 2022, 15:40
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Join Date: Nov 2007
Location: malta
Posts: 177
AMS experience taught me that ATC really wants you to be at fl100- and 250kts- at those points, unless specifically instructed.

So "descend fl070/speed 310kts" means be at or below fl100 (but above fl70) at Sugol/artip/rivier, at speed 310kts. " Descend FL070 with no speed", means 250kts at those points or fl100, whichever comes first.

Regarding abeam points they rarely bother, but do appreciate it if you are not too far away from the Heights.

And they really need you to be at 2000ft when they turn you in for a baseleg at the 18R, if the 18C is also in use.
Might shave some miles of your approach if you know that.
the_stranger is offline  
Old 19th Apr 2022, 03:00
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Join Date: Apr 2009
Location: Canada
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The issue here is whether ATC ever cleared you for the STAR in the first place. There are plenty of times we’ve been close to the first point on the STAR (i.e. our clearance limit for the route) and never received an explicit STAR clearance. Most of the time we query the controller and get an affirmative clearance or a direct or something. (On another note are we are just cleared to fly the STAR if its in the flight plan, without clearance?).

As for assuming if constraints apply, a lot of the time where I fly ATC will explicitly say direct to position XYZ and rejoin the STAR, so we take it to mean that constraints apply unless otherwise instructed or unless we confirm that they don’t. I don’t see how a constraint on a STAR can apply when ATC has given you a direct routing to a point that happens to be on the STAR without any positive clearance to fly the STAR. The fact that waypoint XYZ is on the STAR means nothing if we are going direct and haven’t been cleared on that specific STAR. Otherwise I would expect ATC to inform of us of the requirement to adhere to the constraint either by explicitly stating what speed/alt they want, or by reference to the STAR constraint.
Airmann is offline  
Old 19th Apr 2022, 08:23
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Join Date: May 2001
Location: England
Posts: 1,849

FAQ #5:

5. Is the SID cancelled when the aircraft is cleared direct to a fix along the SID?

No, issuing a CLEARED DIRECT clearance to a waypoint on the SID means the aircraft will leave the SID temporarily, and resume own navigation on the SID at the cleared waypoint. While the restrictions of the bypassed waypoints are cancelled, all other remaining restrictions on the SID are still applicable.

Please note that if the aircraft was cleared direct to a waypoint not on the SID, the aircraft is taken off the SID and is now in a situation similar to that of being vectored off the procedure by ATC.
Superpilot is offline  
Old 2nd May 2022, 12:04
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Thread Starter
Join Date: Feb 2021
Location: Taipei
Posts: 9
OK I think I see now thanks for all the replies!

The thing about non-US airports is they never give you “descend via STAR” clearance but we still comply with the restrictions

It’s those times that they direct us and give us a late clearance that gets confusing

I will try to comply with those restrictions as much as possible next time and query ATC also for the need

From what I understand now if they vectors you out of a STAR or SID when they direct you back to a waypoint on the STAR or SID they will need to rephrase

the restrictions as needed (which I guess they kinda did when they told me descend FL070 speed 250kts)

But they said nothing about doing that at ARTIP so I’m assuming they don’t care (at least I haven’t got an ATC violation from them ha)

Once again, thanks for the replies!
Kevingee21 is offline  

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