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SID and Speed restrictions

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SID and Speed restrictions

Old 22nd Nov 2021, 22:23
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SID and Speed restrictions

I have a question regarding Speed restrictions when following and SID.

When flying out of various UK / London airports the SID will sometimes have Speed restriction of 220 kts and stop altitude 4000 - 6000 with and without step climbs.
As an example if you have an SID with 220 kts speed restriction to various waypoints on the SID, and your initial stop altitude could be as example 5000 ft on the SID, however before reaching this altitude and waypoint, you are cleared to FL100 or FL150, and you get the instruction to Climb Flight Level 150, nothing else in the ATC clearance.

Do you
1. Still adhere with the Speed restriction on the SID? (Despite being cleared to a higher level then the initial Climb level on the SID)
2. Do you still need to respect any climb restrictions (Altitude restrictions) on the SID prior to climbing the cleared level of FL150?
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Old 24th Nov 2021, 07:16
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You instruction will be “climb now FL 150”. That is an instruction to climb to FL 150 i
and all step climb restrictions can be ignored.

the speed restriction of 250kts below FL 100 will still apply unless the instruction “ no ATC speed restriction” is issued.
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Old 24th Nov 2021, 23:12
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Disclaimer: I don't know what the custom is in the UK.
As far as I remember, any speed/altitude restriction on a SID must be explicitly cancelled by ATC ("no altitude/speed restriction [at/after/to FIX]"). I think it's in ICAO doc 4444 but I wouldn't put my finger on it.
(Also, why would you think that a clearance to a higher level would cancel a speed restriction? I'm actually interested from my ATCO-only point of view)

As for the "climb now", although I've heard it mentioned on the web from time to time, I don't believe is standard at all and honestly I think there are a few different ideas of what it means, depending on the ATCO/Pilot you ask.
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Old 24th Nov 2021, 23:32
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From the manual I read the following:
"If there are no remaining published level or speed restrictions on the SID, the phrase CLIMB TO (Level) should be used"

I am sure I have heard the phrase CLIMB TO (Level) while still being in Speed restricted area, ex 220 kts.
In the same GEN part of the route manual, the CLIMB NOW FL - seems only to refer to the vertical restrictions on the SID, and that those restrictions can be ignored if you get the instruction CLIMB NOW, but does not mention anything about speed restrictions.

But you also have the CLIMB UNRESTRICTED which should cover this too.

Then to make things confusing, in the GEN (Clearances on a SID) part there is the following:
So if you get the CLIMB TO (level) without any of the CANCEL LEVEL/SPEED restrictions, that would then mean you follow any Step Climbs, Level restrictions on the SID to the CLIMB TO (level), as you have not been told the climb is unrestricted?
Equally you follow the Speed restrictions on the SID?

The slightly confusing part is going back to the start of the post implying you only get CLIMB TO Level when there are no Speed/Level restrictions left on the SID, and I am sure I have heard that happen with both Speed restrictions and Step Climb restrictions remaining on the SID.

Thanks for your responses.
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Old 2nd Dec 2021, 21:25
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The core phraseologies are:
 CLIMB VIA SID TO (level)
These require the aircraft to:
1. Climb/descend to the cleared level in accordance with published level restrictions;
2. Follow the lateral profile of the procedure; and
3. Comply with published speed restrictions or ATC-issued speed control instructions as applicable.

Phraseologies for removal of speed or level restrictions:
These phraseologies mean that:
1. The lateral profile of the procedure continue to apply and
2. Speed or level restrictions which have not been referred to will continue to apply.
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Old 7th Dec 2021, 01:47
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C_M is correct. Here's the ICAO explanatory leaflet: https://www.icao.int/airnavigation/s...%20Leaflet.pdf.

Amazing thing about using standard phraseology, rather than local inventions and conventions...
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