When to descend?

[TonyC]

You guys have too many balls in the air at once.

That just makes it more interesting.

You're established, in your scenario, when you're on the arc. That means when you're at 12 miles. The +/- stuff is a PTS standard that is not applicable to anything but a Practical Test. You're supposed to stay at the correct distance all the time.

So, I begin the left turn at 13.1, when the DME reads 12.0 I begin my descent. I roll out with too much drift correction, so I eek out to 12.1. Do I climb back up?

I'm not asking for a tolerance. I realize the goal is to maintain 12.0 exactly. But, if 12.0 exactly were required to descend, none of us humans could fly the approach.

Established with respect to any type of course guidance means when you are on the centerline of the course in question.

So, when you're cleared to fly a LOC or VOR or NDB appraoch, are you saying you don't begin descent on final until the needle is exactly centered? Something tells me you either consider yourself established using a more lenient criteria, or you're a heckuva lot better than us, or you do a lot of missed approaches.


Now, whatever criteria it is that you use to maintain that centerline, or determine "established", whether it be measured in degrees or needle widths, or dots, or whatever, they don't apply to an arc. Arcs don't have a "centerline" per se. The only measure I can imagine that would apply to an arc would be measured in Nautical Miles DME. The DME might be an absolute number (say, 1 NM?) or it might be a percentage of the arc (10% of 12 would be 1.2?) or it might be based on aircraft category, or... well, I don't know. I just can't find anything to say, one way or another, what constitutes "established" on an arc for the purposes of beginning a descent.

I've seen an FAA interpretation from the guy in Washington who knows all about what the regs mean (someone here must remember his name - I can't). If you can find him you can probably locate the same source for this info that I did.

Boy, I'd like to meet the guy that knows all about what the regs mean. Does he go by Avbug, by chance?








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[A Squared]

THe Arc has the same protection as an airway, which is to say, 1000' above any obstacle 4 nm from centerline, and 500' tapering to zero from 4nm to 8nm. If a fed or a check airman was looking over my shoulder, i'd probably wait until I had completed the turn onto the arc, merely because it's a grey area and who knows what opinion (right or wrong) that guy holds. ie: the most conservative approach is the path of least resistance when subject to official oversight. Left to my own devices, I have no qualms about starting a descent as I start my turn onto the arc (about 1.5-1.7 NM before the arc) after all I'm 6.5 miles past anything I could possibly hit at arc altitude (assuming correct altimeter setting) and it's another 9.5 nm until anything else I could hit.

 

[PropsR4Boats]

Tony C,

Ask me some specific questions; I will answer them with references. After I do that I will let you take me to Ruth’s and you better not stick me with the bill.

Vectors4fun what facility do you work.

Props

 

[A Squared]

..........In addition once an approach clearance is given altitude is the pilot’s discretion to the lowest permissible altitude, unless there is a specific crossing instruction or other ATC instruction..........

PropsR4Boats,

Can you direct me to exactly where in the AIM it says this?

 

[Yellow Snow]

Vectored and TIS are 100% correct. Established in the hold is when you are centered on the inbound leg. You guys are quoting the AIM like it is regulation and it isn't. The AIM is informational. It is helpful and will make life easier but it isn't regulation. The pattern entries, for example, are nice suggestions but you can enter a pattern any way you like as long as you stay in the protected airspace. If you are cleared for an approach you may, when established on a published segment, descend to the altitude allowed by that procedure.

 

[PA31Ho]

you are 'established in a hold' once established on the inbound leg... great!

Another question, in relation to the barb. Say you are flying straight to ASHLY LOM (IAF), you have to make a right turn initally for the PT, however once you are flying the 018 heading, you have to stay on the left side of that barb? Or can you make a right turn if you'd like?

I just want to clarify some of these questions because some people have different answers than the other when I ask around at the airport, just wanting to get other opinions as well.

Thanks

 

[MTpilot]

Follow the Barb

I didn't look at the approach but the barb denotes the direction of the procedure turn, that is the way you have to go.

 

[TonyC]

Tony C,

Ask me some specific questions; I will answer them with references. After I do that I will let you take me to Ruth’s and you better not stick me with the bill.

Props,

Ya gotta pay attention. I've already asked the question - - read the thread.


What constitutes "established" with regards to an approach segment defined by a DME arc?



I'm not looking for PTS standards. I'm not looking for "maintain certerline." I'm not looking for TERPs obstacle clearance design. I've been through all that, and though it is very informative, it doesn't answer the question, "what is established?".






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[PropsR4Boats]

I see, there was a lot of talk about other stuff. Some people where talking about holds, etc. Hang on and I'll find it for you.

Of course if you just stayed right on course you wouldn't have to worry, just kidding.

Seriously I see what I can find you. Oh by the way there is a Ruth Chris within walking distance of the crew hotel I’m in.

 

[TIS]

You guys are quoting the AIM like it is regulation and it isn't. The AIM is informational. It is helpful and will make life easier but it isn't regulation.

Actually, this is a popular idea but it isn't true - when you have to answer the tough questions from across the big conference table. The FAA treats the AIM as gospel if you become involved in something and they can show that you didn't follow their suggestions. In fact, they use it to help support the 91.13 careless or reckless charge they append to any filing against an airman.

In other words, "You didn't do things the way we said to and now look where you've ended up!"

The pattern entries, for example, are nice suggestions but you can enter a pattern any way you like as long as you stay in the protected airspace.

True to a point. If you're on a practical test of any kind this is NOT true. the PTS specifies that you must use the appropriate entry from the AIM.

If you are cleared for an approach you may, when established on a published segment, descend to the altitude allowed by that procedure.

Correct!

TIS