If I'm at 9000 and the controllers stays "cleared to 5,000" is that an instruction to descend right away? Or does it leave me discretion as to timing?

Is "descend and maintain 5,000" only heard in the US?

I usually double check when they word it like that. Usually, "Decend 5,000" = now...or "descend/cleared 5,000 your discretion"...I've been "Cleared 5,000" and assumed it was my discretion only to get "xx start your descent now" a few minutes later....

If they say "Descend to 5000", you start now. If they say "When ready, descent to 5000" you start when you want.

There is no more descend and maintain 5000 or Pilot discretion. It changed a little while ago to the above phraseology.

They didn't say either of those. They said "Cleared to 5,000" - or possibly "Cleared 5,000", I don't recall which.

By the way, do you have a reference for the phraseology change you mention?

I would have to dig through the archive to see when it changed. IIRC it was about a year or so ago. I stems from confusion about crossing restrictions. In the US a clearance to "descend to 5000 pilots discretion" meant any published crossing restrictions along the way were not required. This was not the case in Canada, but some pilots elected to apply this interpretation. As a result the term "when ready" was adopted to prevent confusion. Clearance to an altitude that includes "when ready" allows you to start your descent when ready.


From the TC AIM:

When used in conjunction with an altitude clearance, means that ATC has offered the pilot the option of commencing the altitude change whenever the pilot wishes. When the change is initiated, the pilot should advise ATC. Pilots may temporarily level off at any intermediate altitude; however, once an altitude has been vacated, the pilot may not return to that altitude because ATC may have reassigned it to another aircraft. Pilots are expected to advise ATC of any temporary level-off at any intermediate altitude. Compliance with any assigned or published altitude crossing restriction is mandatory unless specifically cancelled by ATC.

Descend to xxx, descend to and maintain xxx, cleared to xxx, maintain xxx. They are are the same thing. Unless specified when ready you are required to commence the change when accepted (read back) and perform the change consistent with the normal operating characteristics of the aircraft.

I don't use "cleared" WRT altitude assignment. I also don't use "maintain" unless I am issuing a clearance. I will use "when ready descend", climb xxx, descend xxx. Very little room for confusion this way.

kevenv wrote:I don't use "cleared" WRT altitude assignment. I also don't use "maintain" unless I am issuing a clearance. I will use "when ready descend", climb xxx, descend xxx. Very little room for confusion this way.

In the terminal we do the same. Climb and maintain xxx or Descend and maintain xxx. I know some of the enroute controllers use the cleared option.

And I should have mentioned, Maintain xxx is no longer valid. It must include the instruction to climb or descend.

Last I checked we all had the same phraseology rules?
Eventually the US will catch up with the rest of the world, while some controllers still say Pilots Discretion, and there's little room for confusion it's not valid phraseology anymore. I didn't really agree with the phraseology change, but it's ICAO standards, it's making the aviation world a safer place, although it takes time...

Same concept as "Line up and Wait" instead of the now defunct "position and hold"

Personally, from a pilots point of view, if I were given "Cleared 5000" i'd be descending to 5000, while it's not perfectly clear phraseology you definately wouldn't be wrong to start descending, if you wait there may be consequences to such depending on the traffic picture at the time.

Anyway, like anyone will say, if in doubt ask, if you don't want to ask, then just descend.