Most of the controllers I know just throw in "if unable, maintain X and advise", and then no longer worry about protecting for the hold.
And yes the pilot must hold at that point until above 9000 and continue.
Of course, when the instruction is issued by DCPC or not, you should inform ATC if you have any doubt about not making the altitude.
Especially during procedural separation which is based largely on time estimates, it helps the controller plan ahead since he's controlling on nothing but paper strips.
That being said such instructions can be issued quite often in a radar envrionment, which helps alleviate some controller workload.
I'm not surprised it's not specifically covered in CARS, or any other document. I don't think it need be.cpl_atc wrote: Now, show me where this is stated in the AIM, CARs, or Instrument Procedures Manual. I can find no record of this ATC expectation on the pilot side of things.
I informed TC of as much, and they promised an AIP amendment as a result. That was two years ago, and unless I've missed the change, I'll consider the matter unresolved...
Bottom line is, you as a pilot are given a clearance, (hold, heading, altitude, whatever). If you accept that clearance to must comply. If you can't comply you don't accept the clearance, and its up to the controller to come up with something else.
If you cannot meet an altitude requirement as specified, don't accept the clearance. If after accepting the clearance, time passes and you realise you can't comply, you certainly can't charge ahead in contravention of an accepted clearance. I'm pretty sure you'll find something like that in CARS.