IFR approach altitudes

[Daddy O]

So I have a question. If I am instructed to fly an approach that calls for a specific altitude as I cross a waypoint, but approach/departure/center has me at another altitude. Should I be making an effort to get the altitude specified by the approach? Or just stay at the last altitude assigned by whoever is controlling me?

[steve.huff]

From the AIM. ATC can modify published sids or stars. including routes and altitudes.
for Instrument approach procedures. the pilot may not descend or deviate from the last ATC assigned altitude until"cleared for the approach"
at which time the pilot is expected to fly the published procedure/altitudes. Cleared to the IAF, without being Cleared for the procedure does not count.

[Daddy O]

So the controller will actually say "cleared for the approach" or "clear to fly full approach" and then I will follow the chart?

[Alex Stjepanovic]

In the most simple terms: Unless you are on a published segment, you will be given an altitude to maintain until established on one. You may or may not otherwise be given a specific altitude.


As far as of crossing a way point at a different altitude than that on a chart - Yes you fly what you are assigned(Unless again it seems too high/low/off, in which case you should of course question the clearance). Also don't forget that some approaches have IAFs/Feeders sticking a long way out, in which case if the radials/bearings/localizers/etc are known to be receivable below the MEA's specified for the former, you may initially also be given an instruction to track them inbound/outbound at what might appear like a completely funky altitude, but be given a proper clearance and an altitude later.

I'm not all that familiar with AIM's paragraphs, so I can't find the specifics(Maybe Steve can), but if you are in the mood to read it, here's the ATC side of things: http://www.faa.gov/air_traffic/publicat ... 408.html.1

Does this answer it?

[steve.huff]

AIM Chapter 5 covers Air Traffic procedures. http://www.faa.gov/air_traffic/publicat ... ap5toc.htm
specifically 5-4 Arrival Procedures. these are interesting reads for government publications. Please correct me if I am mistaken, but there
are two understandings. 1) ATC may amend a published procedure/IAP/Star/Sid as needed for vertical or altitude separation.In effect ATC vectors or altitudes supersede published routes or altitudes. Second, On a IFR clearance until a pilot is cleared for a procedure they can not execute the published procedure. But, of course there is always exercising PIC Authority. But then you will probably have to make a phone call when your on the ground.

[Alex Stjepanovic]

1) Yes they can, and whenever you are taken off(Or even on in some cases) one with specific altitudes listed, you will be told what to do/maintain, altitude-wise.

2) Not going there as I'm neither a real world pilot or ATC