Conditional Clearance

[N301MB]

Just wondering what a pilots preference would be when given a conditional climb/descent clearance -


climb/descend to FLxxx, to be level

- in xx minutes
- in xx miles
- xx miles before a point
- crossing a point

and what if any would be reason for preference

[westhawk]

I prefer receiving clearances to cross a fix or distance before/after a fix since VNAV mode is pretty handy at providing guidance for getting there accurately. Even in aircraft without this capability I find my meager mental math skills sufficient for this purpose. Geographically referenced descent clearances are usually given when either terrain or airspace usage constraints are the driving factor determining the altitude constraint.

While I might not particularly prefer time dependent climb/descent clearances I fully understand that ATC may find them more convenient when the purpose of the time constraint is to ensure proper traffic separation. I LIKE missing the other traffic! I surmise that ATC issue clearances in this way due to the way that they calculate closure rates and crossing times between traffic.

In the end my overriding preference is to fit into the system and complete my flight safely so I'll do whatever it takes to make that happen!

[gorter]

I also personally prefer cross point xx at FLxxx, but I'm used to doing anything needed. France wants level in x minutes, Germany gives a minimum ROD, UK gives a point. You ask and I shall do my best to comply. Just don't ask me to reduce the speed once I've started to go down and still expect me to be able to make the level. One or 'tother.

But most ATC understand that issue.

[Denti]

I don't like "in xx miles", but the rest is fine. Doesn't really matter at all which i use, all are easy to do.