Question about level Clearances

[nitefiter]

Guys
Whats the story regarding the following ATC clearance which i was given on two separate occasions yesterday?
"Descend now FL190 and when ready descend FL120".
This caused some confusion,because we could have taken gentle descent to FL120 then which would have given us better speed in the descent and got us out of a 75kt headwind,but the initial clearance only cleared us to FL190.
In the end we just descended to FL190 and levelled off and before we could descend we had been cleared again to FL120.

[Spank me baby!!!]

Hmmm, sounds like poor technique. In Australia we aren't allowed to assign more than one level for that very reason, to prevent confusion.

Had you requested FL190? Were you inbound and approaching your descent point? If so, it sounds like you were given your request, and the controller was also giving you a further "when ready, descend FL120", thinking that when you reach your profile descent point, that you'll leave FL190 and descend FL120. If the clearance to "descend FL120" was re-stated, either the controller realised their error, or a trainee was on and the instructor corrected the trainee.

But then, I'm only guessing. Need more info.

:hmm:

[Jerricho]

Hmmm.........does sound kinda confusing? Where were you ?

[eyeinthesky]

It's fairly common amongst my colleagues and I in the UK.

I suggest the scenario was something like this:

You were at a level above FL200. The controller had traffic at FL200 which he knew would conflict with you if you were left to descend when ready all the way down to FL120. So by pushing you down to FL190 he solved the conflict against the FL200. However, he probably realised that this would put you below your usual descent profile so, with no further conflicting traffic between FL190 and FL120, he left it up to you when to descend to make FL120 by any restriction point or on your descent profile.

Sound reasonable?

I often do it on GW/SS arrivals from COA which come in descending to FL270. They need to be FL180 at LOGAN, but there is often crossing traffic at FL240, so I will descend the SS/GW 'now' to FL 250 and then FL230 to get underneath. The descent from FL230 to FL180 Level LOGAN will then be 'when ready' (provided there is no further conflicting traffic).

[nitefiter]

jerricho
north of london northbound towards TNT @
FL340 cleared descend FL200 level 65 nm before POL.
Eyeinthesky
yes does sound plausable but could have been given two separate clearances which would have ruled out any chance of a balls up.
Cheers.

[Don't Tell Him Pike]

MACC SE get the traffic at FL200 25 miles before TNT (65ish before POL). They have to get you out of 195 before TNT to avoid entering Sector 29. MACC SE then have to meet a standing agreement of FL 120 level before you cross the MCT 080 radial (5 before Denby or 20 before POL).

So what you got was decsend now to 190 to duck under S29, with further descent to 120 to meet the standing agreement. Of course if you're ready to drop to 120 as soon as you leave 200, that's fine, because it's as cleared. I tend to say "Descend now FL190, and further descent at your discretion FL120 level 10 miles before Denby".
I think that's less ambiguous as it allows you to set your own descent profile for a continuous drop, or to level at 190 if you prefer. Of course it's not correct phraseology as per MATS Pt1 or CAP413.

(Why level 10 before Denby? I like to have a bit of breathing space!)

[nitefiter]

DTHP
Thanks, that explains it,but i think ill always confirm the FL120 level once at FL190.The 10 before Denby bit suits the arrival for 32 EGNM cos with the descent and an anticipated direct centre fix we can get the height off no problem.