Question for Americans

In the Canada forum, there's a "Question for Canadians". There's a couple major differences between US and Canadian rules that confuse both of us when crossing the border into the other's territory. There's one Canadian airport in my neck of the woods that's controlled by US ATC. So that leaves me wondering on the differences.

In Canada, "cleared for approach...." means altitude is now pilot's discretion, assuming charted restrictions are met. I've been in cruise, way up high, ask for descent, and get an approach clearance instead. That means, descend and do whatever I want with altitude to transition to the approach. My understanding is it's different in the US.

Now for my question. In the US, when am I allowed to descend below the last cleared altitude and begin the approach?

When established on a published segment of the instrument approach.

Yes. If you are "cleared for the approach" it will usually be accompanied with a statement like "fly heading 270, maintain 3000 till established, cleared for the ILS 24 approach. So you hold the last assigned altitude (3000 feet), then when on the coarse or localizer, you can either stay at 3000 to grab the Glideslope, (if it's an ILS), or you can descend to the charted altitudes as appropriate. Some approaches have "at or above" altitudes, some have mandatory altitudes. But to answer your question, once cleared for the approach, you can descend to meet the chatted altitudes, and descend for the MDA or MDH or the DA. You have to follow the coarse even if you get the airport visually, unless you get cleared for a visual approach.

I reread your question. I believe you are describing a cruise descent clearance, which is not common at all. If you are way up high, and doing a GPS or RNAV approach, and they clear you for the approach, I think you need to maintain your last assigned altitude until you are on a published segment, then you can descend.

There is a similar clearance that can be issued in the US. It’s a cruise clearance. We would often get them flying in less crowded airspace out west. “Delta 1465 cleared to cruise Bozeman”. That cleared you from cruise altitude all the way through the approach with no further communication needed. I suspect you have the clearance in Canada because of the low volume of traffic. I actually got a cruise clearance into ATL once but it was 3AM.

Taltruda said:

I reread your question. I believe you are describing a cruise descent clearance, which is not common at all. If you are way up high, and doing a GPS or RNAV approach, and they clear you for the approach, I think you need to maintain your last assigned altitude until you are on a published segment, then you can descend.

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To clarify, "way up high", haha. Usually the approach clearance will come at 7000 to 10000', 10-20 miles back from the IAF, and approaching the previous descent clearance limit. In my area, that's way too high to successfully descend on the approach, after the initial fix. I'd need to descend at an angle comparable to a brick. It's rare, but I've been given the approach clearance up in the high teens as well.

Quite often, I hear Canadian ATC giving approach clearance to a US airplane with the phrase "cleared approach ___, further descent your discretion". That last part is redundant in Canada, since the approach clearance implies descent is pilot's discretion. However the controller makes that statement to avoid the confusion over the rule difference.

Taltruda said:

If you are "cleared for the approach" it will usually be accompanied with a statement like "fly heading 270, maintain 3000 till established, cleared for the ILS 24 approach

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Using an RNAV example, would ATC ensure that the last cleared altitude is within a reasonable window crossing the initial fix that would permit a normal descent and landing? Eg, "descend 4000, cleared RNAV...."

David Z said:

Using an RNAV example, would ATC ensure that the last cleared altitude is within a reasonable window crossing the initial fix that would permit a normal descent and landing? Eg, "descend 4000, cleared RNAV...."

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This has been my experience. ATC will give one or a series of new altitude clearances to get you down to a reasonable altitude (usually at the charted entry altitude or 1000 higher) for you to begin the approach. Sometimes, when traffic is light, we get "descend to 3000 at pilots discretion." This means we can start the decent when we want and at any decent rate. Without the PD, we are expected to start the decent immediately and at least 500 FPM. The approach clearance will come later and often with a minimum decent level. I have never received a cruise clearance, but don't fly IFR daily, like the airline guys.

Larry

High Altitude Approach

A long, long time ago I use to fly military aircraft and there was something called a “High Altitude Approach” that we often flew.

The high altitude approach basically allows aircraft, when cleared for the approach, to transition from the high altitude structure to a position inbound aligned with the FAF with altitudes defined on the approach for the inbound turn and various altitude requirements to the FAF, then all the way to DA. It also defined the maximum distance you could be from the VOR/Tacan (IAF) for the inbound turn.

Haven’t flown one of these in years since my RV doesn’t operate in the Flight Level structure (Class A airspace). “Cleared for Approach” meant you were cleared to your decision altitude but tower still had to give “Cleared to Land” instructions.

I do miss those days!

Tankerpilot75 said:

A long, long time ago I use to fly military aircraft and there was something called a “High Altitude Approach” that we often flew.

The high altitude approach basically allows aircraft, when cleared for the approach, to transition from the high altitude structure to a position inbound aligned with the FAF with altitudes defined on the approach for the inbound turn and various altitude requirements to the FAF, then all the way to DA. It also defined the maximum distance you could be from the VOR/Tacan (IAF) for the inbound turn.

Haven’t flown one of these in years since my RV doesn’t operate in the Flight Level structure (Class A airspace). “Cleared for Approach” meant you were cleared to your decision altitude but tower still had to give “Cleared to Land” instructions.

I do miss those days!

Click to expand...

We need the ATP to answer this but I think the STAR (standard arrival) will accomplish this 100nm (or more) out. Flying 100nm from ORD I have stumbled into the corridors and linked the high traffic there to STAR's. I believe the STAR provides lateral but waypoint crossing altitude(s) is often specified by ATC in the clearance. I dont fly them but my 10Friend regularly gets them flying (IFR) into the Atlanta area.

Digital Procedure lookup by Airport.

Correct, a STAR may contain lateral, as well as vertical guidance, and also speed restrictions. The speeds always apply unless you get relief from the controller, however, the altitudes only apply if given a “Descend Via” clearance. If they just say “Descend to and maintain 3000 feet”, you would comply with the speeds, but you don’t have to meet the altitudes on the arrival.