Originally Posted by
Hoosten
Whinging about not getting a 'left or leaving' call. Why? It's alarmed..
No, it isn't. If you've been given a 'when ready' descent, there will not be any active alert when you leave your level. All that will happen is a '>' symbol will become a '˅' symbol and
three digits on your track label will begin decreasing. There is no beep, alarm, notification or any active system means of alert.
the new system does notify us so we don't require a 'leaving' call as we will be notified electronically'
Partially true, or at least partially understood and slightly out of context. If an aircraft is within surveillance coverage and somewhere between its current level and its cleared level (and traveling the right direction) there will be no alarm. If an aircraft steps outside of these bounds it will generate a CLAM alert (Cleared Level Adherence Monitor). A track has a 200ft tolerance applied from the cleared level and the CLAM alert will only be generated outside of this tolerance. F350 can wander between FL348 and 352 without alert. An aircraft in a block FL350B370 can wander between FL348 and 372 without alert. An aircraft at FL350, assigned FL250 'when ready' will not generate an alert until it hits FL247 descending. We don't need alarms to tell us an aircraft is complying with its clearance, it's not particularly good HMI to have 'Everything's OK Alarms'.
There is also the Predicted Flight Level (PFL) alert for aircraft equipped with Mode S transponders. This will compare the Cleared Flight Level for an aircraft track to its down-linked selected flight level and generate and alert if a discrepancy exists. This is when you'll hear "Confirm assigned level" from ATC, there is no display presented to ATC of what level is selected, only that there is a difference.
Moving on...
ATC will have several aircraft under their jurisdiction at any point in time, in moderately busy times, I typically had 25-30 aircraft on my combined frequencies, at busy times 35+ (more than I had time to count). The most I had one night with everyone on the rails was 75 aircraft in my airspace. This doesn't include aircraft approaching my volume of airspace, those of which are getting the lions share of my attention because if the flight wasn't been planned through my airspace before it reached me, I was already five steps behind. Add to this the 'behind the radio' work of coordinating with other sectors, FIRs, managers etc.
If you were given 'when ready' descent by me then and didn't advise leaving, there's a pretty high chance that it would go unnoticed in the short term. I would not be instructing aircraft to 'report leaving' the cruise level because it's expected that you do it and a waste of radio time on my behalf if I did.
There are reasons why full descent may not be issued with 'when ready' from the cruise level, generally they include conflicting traffic, airspace or procedures. The controller my not be responsible for the underlying airspace at the time that descent was issued and can't clear you through another controllers airspace. It can also be for task trigger actions such as a frequency transfer gets issued at top of descent when the aircraft reports leaving.
That said, if the first that I knew that an aircraft was descending on their clearance was the pilot piping up saying they were approaching their cleared level I'd just give more descent and move on, I don't see the point of point of being bitchy of frequency, there's more important things to do. Some ATCs, just like some pilots, have their grumpy days, their pet hates, their long tiring shifts, and days when they got out of the wrong side of bed.
For the original post, maybe the controller was approaching the end of a long shift, genuinely didn't notice you leaving, believed he had missed your call and got a smart-arse (and incorrect) response in return for the explanation offered. Maybe he's just a tool. Most likely, as with all things, it's somewhere in between.
I appreciate pilots asking these questions, we can't learn from each other if we don't ask. I encourage my colleagues and trainees to do jump seat flights when ever they get a chance, it's a great way of seeing your world for a few hours.I also encourage all the pilots I meet while doing so to visits towers and centres to get that same experience.
If anyone one has spare time in Melbourne or Brisbane or at any tower location, give us a call, come visit and have a chat. I believe the more that we all know about each others jobs, the better it gets for everyone. The rising tide and all that...
Ask more questions.
What have you got next?