Established on the approach - Checkride question

"Ron Natalie" writes:

It's a little different here, because MSA is operational -- we have
an altitude we can descend to as soon as we're within 25 nm.

The MSA is for emergency use only. You shouldn't be relying on it
for normal operations.

As I mentioned in the bit you quoted, it's different up north -- in
Canada, MSA *is* operational. If you are cleared for an approach and
not given an explict altitude restriction, you are automatically
allowed to descend to the lowest of the following (see RAC 9.3 in the
Canadian AIP):

(a) MEA

(b) published transition or feeder altitude

(c) MSA

(d) 100 nm safe altitude

(e) if nothing else applies, 1000 ft above the highest obstacle within
5 nm (1500 ft or 2000 ft in mountainous areas)

Typically, when you're being vectored and then are cleared for an
approach before you're inside the protected area, MSA will be the
winner (assuming that you're within 25 nm of the IAF) -- descending to
MSA was a standard part of almost every practice approach during my
IFR training, especially the full-procedure ones.


All the best,


David

So as a practical matter, assuming you are able to figure out the
misleading nature of the clearance, what would you do?

This is a difficult question when the ATC guy doesn't understand the
approach. Like the case I mentioned at my own airport, ATC vectored
us at 2,500, but expected us to descend to 2,000 once on the
localizer, even though the chart didn't permit the descent.

My requests for "lower" were met with a bit of disdain when the
controller told me to fly the approach chart, which he *thought* said
2,000.

Some of your suggested dialog makes me a little uncomfortable, because
it seems to lend itself to some miscommunication between ATC and the
pilot about who is providing terrain clearance. (This was the essence
of the TWA514 accident.)

I suppose the easiest answer is to ask ATC to inform you when you're
within 10 nm of the NDB.

get is usually something like "on interception, descend to ..."
rather than "when established on the approach, descend to ...".
That's less ambiguous.

Yes, it is. Still, sometimes we get "until established on the
localizer", but it has the same meaning as "established on the
approach". ATC just doesn't understand the difference.

I see why it's a sensible practice to construe it that way, but is
it officially defined that way somewhere?

TERPS par. 234:

....When no fix marks the beginning of the intermediate or final
approach segment associated with the procedure turn, these segments
are deemed to commence on the inbound procedure turn course at the
maximum distance specified in the procedure.

Greg Esres wrote:

get is usually something like "on interception, descend to ..."
rather than "when established on the approach, descend to ...".
That's less ambiguous.

Yes, it is. Still, sometimes we get "until established on the
localizer", but it has the same meaning as "established on the
approach". ATC just doesn't understand the difference.

The ATC Handbook requires the use of the phrase "...maintain X,000 until
crossing ACME fix..." when a vector is given to a non-published
extension of the intermediate segment. The phrase "until established"
is appropriate only when the vector is to within a published segment of
the approach. This was brought to ATPAC a couple of years ago, and
supposedly controllers were reminded of the difference in an Air Traffic
Bulletin.

"endre" wrote in message
om...

I did my instrument checkride the other day and passed...

Question for this group.

I was being radar vectored for the SHN NDB approach. I was cleared in
the following way: Cessna 61786 14 miles from NDB descend and maintain
2000 until established.


That was all of it? There's no approach clearance there.



The problem: I was outside the 10 mile ring on the plate, established
on the inbound course, no way to tell when I would be inside 10 mile.
However, I would need to descend to 1400 before the NDB to have a
chance to descend to MDA of 900.

What would you all do?


If what's above is a verbatim quote of the instruction received, I'd request
an approach clearance.

I'm not sure what your concern is. The ten mile ring means nothing with
regard to where you can begin your descent.

"Greg Esres" wrote in message
...

Argh! No! The PILOT must know when he's established and within the
protected area. All you've intercepted is a navaid, not a segment of
the approach, until you've reached the start of that segment.


Actually, assuming a proper clearance is issued, it is OK. The controller
must assign an altitude to maintain until the aircraft is established on a
segment of a published route or instrument approach procedure. Once you're
established on a published segment you can descend to the appropriate
altitude for that segment.



What ATC intends is irrelevant. If they want you at the published
altitude before you reached the point where that altitude applies,
then they're got to clear you down to it, using their MVAs.


There's a question here about the clearance; either ATC issued an improper
clearance or it was quoted incorrectly. But ATC did issue an altitude to
maintain until established, 2000 feet.



Failure to understand this concept has killed some people in the past,
including at least 1 airliner, TWA 514.

See the AOPA article:

http://www.aopa.org/asf/asfarticles/sp9806.html


Bad example. TWA514 was not vectored for the approach, they simply
descended below the published altitude for their route.

"Greg Esres" wrote in message
...

We had a local approach where we often got vectored to a point on the
extended centerline of the final approach course, but outside the
point where the approach started. The published altitude was 2,000
feet, but we were vectored at 2,500. ATC *wanted* us to descend
immediately on intercepting the localizer, but the approach simply did
not authorize that.

If ATC wanted us at 2,000, then it was their responsibility to assign
that altitude, because only then are they providing obstacle
protection. If a pilot allows himself to be intimidated down to an
unpublished altitude, then there is no obstacle protection being
provided by anyone, and the pilot is in violation of Part 97.


What approach is that?

Dead reckoning? If the course intercept time and length are too difficult
to interpolate safely and fly the airplane, I'd request a position update in
5 minutes (7.5-10 miles closer), or the PT.

The no way to tell where you are part of your question should be (in my
limited experience) a BIG RED FLAG, both for the approach and how you
conduct the flight in general. Ultimately, keeping your butt out of the
rocks is solely up to you.

"endre" wrote in message
om...
I did my instrument checkride the other day and passed...

Question for this group.

I was being radar vectored for the SHN NDB approach. I was cleared in
the following way: Cessna 61786 14 miles from NDB descend and maintain
2000 until established.

The problem: I was outside the 10 mile ring on the plate, established
on the inbound course, no way to tell when I would be inside 10 mile.
However, I would need to descend to 1400 before the NDB to have a
chance to descend to MDA of 900.

What would you all do?

Endre

"Steven P. McNicoll" wrote in message
nk.net...

"Greg Esres" wrote in message
...

We had a local approach where we often got vectored to a point on the
extended centerline of the final approach course, but outside the
point where the approach started. The published altitude was 2,000
feet, but we were vectored at 2,500. ATC *wanted* us to descend
immediately on intercepting the localizer, but the approach simply did
not authorize that.

If ATC wanted us at 2,000, then it was their responsibility to assign
that altitude, because only then are they providing obstacle
protection. If a pilot allows himself to be intimidated down to an
unpublished altitude, then there is no obstacle protection being
provided by anyone, and the pilot is in violation of Part 97.


What approach is that?


My question too...

Chip, ZTL