7600 Descent

Captain

Captain

Final Approach
Joined
Mar 12, 2012
Messages
8,002
Location
NOYB
Display Name
Display name:
First Officer
On my 'other forum' there is a debate going on as to when to start the descent if IMC and lost comms. 'They' are saying to cross the IAF at the highest of the Cleared, Filed, Expected rule. So if you're filed at FL390 cross the IAF there and then start down.

I say that's crazy talk and can't imagine that is what ATC wants. What say this board?
 
Sometimes what you're supposed to do doesn't always make the most sense nor does it scale to all situations that well.
 
Captain said:
On my 'other forum' there is a debate going on as to when to start the descent if IMC and lost comms. 'They' are saying to cross the IAF at the highest of the Cleared, Filed, Expected rule. So if you're filed at FL390 cross the IAF there and then start down.

I say that's crazy talk and can't imagine that is what ATC wants. What say this board?
Click to expand...
That is absolutely the right thing to do. You are bound by the altitude per route segment rule until you run out of them at the IAF. Even then, in the event you were given holding there, you can't start down until your EFC. In the case of having been given holding at the IAF without an EFC, you can't start down until your updated ETA at the destination.

Be glad you didn't have to learn it before ATC changed the lost comm rule to eliminate the "Expect Approach Clearance Time" procedure those my age or older had to learn. You newbies got it EASY!

dtuuri
 
Last edited:
NAVAID reception at the IAF would be a little difficult at FL390.
 
Any STARs into said airport?

I'm pretty sure nowadays ATC just plows the road for you, and you can pretty much just fly it at your discretion. They want you out of the airspace as soon as practicable, and so flying at FL390 to the IAF, and circling, circling circling circling downward is going to cause them more headaches. I'd just shoot for a 1500' fpm descent to put you at any crossing altitudes for the STAR/Approach.
 
Last edited:
EdFred said:
Any STARs into said airport?

I'm pretty sure nowadays ATC just plows the road for you, and you can pretty much just fly it at your discretion. They want you out of the airspace as soon as practicable, and so flying at FL390 to the IAF, and circling, circling circling circling downward is going to cause them more headaches. I'd just shoot for a 1500' fpm descent to put you at any crossing altitudes for the STAR/Approach.
Click to expand...
And if there's somebody right below you who ATC can't talk to either?

dtuuri
 
dtuuri said:
And if there's somebody right below you who ATC can't talk to either?

dtuuri
Click to expand...


You have to come down eventually. There's always a chance there's someone else ATC can't talk to when you descend - whether you fly at 390 the whole way, or start down early. When I had a tower/TRACON tour, I asked this question, "do you guys want book procedure or what do you really want?" They basically said they clear everyone from your path, and not to worry about expected cleared filed altitudes or EFC. They can usually figure out what you are doing based on your radar return. And they'd rather have you out of the system sooner if you arrive at your EFC early.

The one time I had a 7600, I bailed from my plan ASAP. I knew I had terrain avoidance and descended immediately. It was either that, or fly the next 3 hours incommunicado. Of course at 390 you are VMC, and should be able to find VFR weather somewhere.
 
Last edited:
EFC only applies if he was given a hold. If his clearance limit was the airport (almost always is), there's no reason to hold.
 
roncachamp said:
You're the one that raised the issue; "And if there's somebody right below you who ATC can't talk to either?" That possibility exists wherever you start down.
Click to expand...
The longer everybody stays put, the more time ATC has to sort things out. If two planes reach the same IAF for the same airport at different altitudes, before communications are established, and then let down in a hold--there's no way they'll ever hit each other even if one catches the other because for years controllers have been telling me no two pilots can fly the same track in any holding pattern they've ever seen on radar.

dtuuri
 
EdFred said:
When I had a tower/TRACON tour, I asked this question, "do you guys want book procedure or what do you really want?"
Click to expand...
ATC's fingerprints are all over the current rule--they OWN it. A couple years ago I wrote them and asked them to explain it and they punted my question to the Chief Counsel instead of manning-up. From the controller's perspective, they want to clear the air because they have no idea what you might HAVE to do next. But if you don't actually NEED to do drastic stuff, be cool and follow the rule. Back when I was spending time in a fuel guzzling Lear 23 with the Low Fuel lights typically coming on during descent, staying up at FL410 as long as possible made a lot of sense. Then, you did have to linger until your planned ETA before descending, but ATC scrubbed that part in the 1980s. So, it's their ball game. Let them change it if they want, but put it in writing if they do.

dtuuri
 
Last edited:
dtuuri said:
The longer everybody stays put, the more time ATC has to sort things out.
Click to expand...

ATC has it sorted out well before you do.

If two planes reach the same IAF for the same airport at different altitudes, before communications are established, and then let down in a hold--there's no way they'll ever hit each other even if one catches the other because for years controllers have been telling me no two pilots can fly the same track in any holding pattern they've ever seen on radar.
Click to expand...

That applies to flying in general.
 
Steven- Sometimes you add value to the forums, and other times you're just banging your keyboard. This is one of those latter times.

Yes, pun intended sir.
 
Oh, this is a fun puzzle.

If you're cleared to an airport, is this the part of 91.185 that applies?

(2) If the clearance limit is not a fix from which an approach begins, leave the clearance limit at the expect further clearance time if one has been received, or if none has been received, upon arrival over the clearance limit, and proceed to a fix from which an approach begins and commence descent or descent and approach as close as possible to the estimated time of arrival as calculated from the filed or amended (with ATC) estimated time en route.​

So, if you were cleared direct to your destination airport at FL390, you fly over that airport at FL390, then you stay above that airport (in a hold?) at FL390 until the time en route that you filed has elapsed, and then you begin a descent to some IAF (using a hold if necessary?) and then you can do the approach and land.

That seems pretty weird.
 
NoHeat said:
Oh, this is a fun puzzle.

If you're cleared to an airport, is this the part of 91.185 that applies?

(2) If the clearance limit is not a fix from which an approach begins, leave the clearance limit at the expect further clearance time if one has been received, or if none has been received, upon arrival over the clearance limit, and proceed to a fix from which an approach begins and commence descent or descent and approach as close as possible to the estimated time of arrival as calculated from the filed or amended (with ATC) estimated time en route.​

So, if you were cleared direct to your destination airport at FL390, you fly over that airport at FL390, then you stay above that airport (in a hold?) at FL390 until the time en route that you filed has elapsed, and then you begin a descent to some IAF (using a hold if necessary?) and then you can do the approach and land.

That seems pretty weird.
Click to expand...

100% correct and this is what I would expect you to do.
 
Last edited:
MarkZ said:
100% correct and this is what ATC expects you to do.
Click to expand...

I've read numerous posts from controllers on this subject, and I'm not sure I've seen even one of them say that they expect that.
 
So;

Librarians agree the letter of the reg requires a pilot to over fly the IAF at FL390 and actual pilots and controllers agree that makes no sense and isn't expected.

Do I have that right or olis another few pages needed to get to the bottom of this?

:) :) :)
 
I edited my post. Not the first time I've been wrong about something...though I am now curious what the "correct" answer is.

Part 91 is correct (in my eyes and my colleagues I've spoken to here at ZAU). I still protect airspace for the NORDO from cruising altitude down to the ground, but I am expecting the aircraft to fly the clearance as given/amended until the clearance limit, then initiate a descent at the clearance limit or IAF, holding if necessary.
 
Last edited:
Now that you've edited your post, you make Captain's post #27 absurd. Oh, brother....
 
Typically the clearance limit is the airport. How does that factor into this or does it? Also, many times the route is to some fix/VOR that is NOT and IAF direct to the field. Does that change anything?
 
Captain said:
Typically the clearance limit is the airport. How does that factor into this or does it? Also, many times the route is to some fix/VOR that is NOT and IAF direct to the field. Does that change anything?
Click to expand...
"Typically" you're cleared to the "destination airport". If they limit your clearance they give you holding instructions and an EFC. Holding pattern templates aren't based on airports. The route is supposed to be spelled out accurately in the flight plan, so it's assumed you know a way to get directly from the the last fix to an IAF or at least have a feeder to it.

dtuuri
 
Yup, the quotes around key words of what I said make it better. Thanks.
 
dtuuri said:
"Typically" you're cleared to the "destination airport". If they limit your clearance they give you holding instructions and an EFC. Holding pattern templates aren't based on airports. The route is supposed to be spelled out accurately in the flight plan, so it's assumed you know a way to get directly from the the last fix to an IAF or at least have a feeder to it.
Click to expand...

An EFC is not issued when no delay is expected.
 
Yeah, my last reply only applied to the first sentence. The rest I simply don't agree with. You don't always get a hold when your clearance limit is changed (as Steven said), and often the route isn't mine...it assigned so the last fix being an IAF or having a feeder isn't 'assumed'.

Look, I don't know the answer here. I'm asking the question. Am I the only one who thinks flying over the IAF at FL390 seems silly?
 
Captain said:
Am I the only one who thinks flying over the IAF at FL390 seems silly?
Click to expand...

Mark your calendar: I agree with you 100%! :D

(I'm not saying my opinion matters, though.)
 
In thinking further about this scenario, the likelihood of a complete radio failure in an aircraft at FL390 is unlikely considering the backup systems and redundancy inherent to such aircraft flying at that altitude. Now, if you are at 8000' in a typical GA aircraft, that's a different story.
 
Captain said:
You don't always get a hold when your clearance limit is changed (as Steven said), and often the route isn't mine...it assigned so the last fix being an IAF or having a feeder isn't 'assumed'.
Click to expand...
Can you give an example of how that would be a problem if you were trying to follow 91.185?

dtuuri
 
Lucky said:
In thinking further about this scenario, the likelihood of a complete radio failure in an aircraft at FL390 is unlikely considering the backup systems and redundancy inherent to such aircraft flying at that altitude. Now, if you are at 8000' in a typical GA aircraft, that's a different story.
Click to expand...

+1 that was my thought reading this earlier. I have three different radios, AFIS, CPDLC (not sure how much good that would do in the US), two different SAT phone systems, email, and VOIP to try if needed.
 
Speed said:
+1 that was my thought reading this earlier. I have three different radios, AFIS, CPDLC (not sure how much good that would do in the US), two different SAT phone systems, email, and VOIP to try if needed.
Click to expand...

Exactly right. I have 3 VHF, 1 HF, email/SMS on the flight deck (data link) and SAT phone. Pretty typical really.
 
You must log in or register to reply here.
Back
Top