Crossing a stepdown fix high

Is there any problem with controllers or examiners if I cross a stepdown fix
several hundred feet above the depicted altitude? I believe that, legally,
I can be at any altitude above the crossing minimum, but would this be a
bust of the PTS +/-100 tolerance, or cause a problem for ATC?

For example, take the SEA VOR 34L/R approach. Assume you are cleared for the
approach at 5000ft. Profile is 5000 at FACTS - 6nm - 3000 at MILLT - 6.7nm -
1600 at DONDO, which is the last fix before descent to the MDA. I can set up
a nice smooth descent at 300fpnm, arrive at 1600ft well before DONDO, and
avoid even thinking about a level-off by crossing MILLT something above
3200ft. Would that be a checkride ding?

-- David Brooks

When I was an examiner, I would have expected you to fly the approach
profile as published. Once upon a time I decided to forego the "descent and
maintain 2200 feet" on the way in to BFI's ILS 13R, thinking that I would
stay at 3000 and intercept the glideslope high....got chided by Seattle
Approach for doing so. Over the years I have learned that ATC expects you to
do the expected.

Bob Gardner

"David Brooks" wrote in message
...
Is there any problem with controllers or examiners if I cross a stepdown
fix
several hundred feet above the depicted altitude? I believe that,
legally,
I can be at any altitude above the crossing minimum, but would this be a
bust of the PTS +/-100 tolerance, or cause a problem for ATC?

For example, take the SEA VOR 34L/R approach. Assume you are cleared for
the
approach at 5000ft. Profile is 5000 at FACTS - 6nm - 3000 at MILLT -
6.7nm -
1600 at DONDO, which is the last fix before descent to the MDA. I can set
up
a nice smooth descent at 300fpnm, arrive at 1600ft well before DONDO, and
avoid even thinking about a level-off by crossing MILLT something above
3200ft. Would that be a checkride ding?

-- David Brooks

David Brooks wrote:
Is there any problem with controllers or examiners if I cross a stepdown fix
several hundred feet above the depicted altitude?

I doubt a controller would even notice (or care).

The examiner probably will, and might ding you on it if you didn't
explain why you were high. It sounds like you've got a perfectly good
plan, however, and I suspect most examiners would be impressed with
the level of pre-flight planning you put into this if you explained it
ahead of time. The last thing you want to do on a checkride is do
something unusual without explanation -- that leaves the examiner to
come up with his own explanation, and it might just be that you're
behind the airplane.

On the other hand, don't just cross fixes high for no good reason.
Depending on the approach, if you don't keep up (down?) with the
step-down fixes, you may find yourself having to divebomb at the end
to reach the MDA before you reach the MAP. I don't have a chart of
the approach you're talking about, but the way you describe it, it
sounds like you've already thought about that.



I believe that, legally,
I can be at any altitude above the crossing minimum, but would this be a
bust of the PTS +/-100 tolerance, or cause a problem for ATC?

For example, take the SEA VOR 34L/R approach. Assume you are cleared for the
approach at 5000ft. Profile is 5000 at FACTS - 6nm - 3000 at MILLT - 6.7nm -
1600 at DONDO, which is the last fix before descent to the MDA. I can set up
a nice smooth descent at 300fpnm, arrive at 1600ft well before DONDO, and
avoid even thinking about a level-off by crossing MILLT something above
3200ft. Would that be a checkride ding?

"David Brooks" writes:

Is there any problem with controllers or examiners if I cross a stepdown fix
several hundred feet above the depicted altitude? I believe that, legally,
I can be at any altitude above the crossing minimum, but would this be a
bust of the PTS +/-100 tolerance, or cause a problem for ATC?

There's an interesting article from a 1998 Transport Canada newsletter
called "CFIT - Why are aircraft flying at minimum IFR altitudes?":

http://www.tc.gc.ca/civilaviation/an...rna/new198.htm

One of the major recommendations is that the only time a pilot should
fly at (rather than above) a minimum IFR altitude is MDA when weather
conditions require; otherwise, leave a healthy safety margin. Of
course, you'll have a hard time convincing a flight test examiner of
this, but in real life, it makes sense to me -- my plane is a lot
slower and can descend at a lot steeper angle than a big airliner, so
I don't need a long, shallow approach slope anyway.

Besides, ATC doesn't always know what approach you're flying anyway.
Are you on the ILS 25, the LOC 25, the LOC/DME 25, the NDB 25, the
NDB/DME 25, or the GPS 25? In my (so-far limited) experience,
sometimes they mention a specific approach and sometimes they do not.


All the best,


David

"Bob Gardner" writes:

When I was an examiner, I would have expected you to fly the approach
profile as published. Once upon a time I decided to forego the "descent and
maintain 2200 feet" on the way in to BFI's ILS 13R, thinking that I would
stay at 3000 and intercept the glideslope high....got chided by Seattle
Approach for doing so.

But in that case, if I understand correctly, you had a specific
instruction from ATC to descend to 2200 -- that's different from
step-down altitudes in a published IAP.


All the best,


David

In a previous article, David Megginson said:
One of the major recommendations is that the only time a pilot should
fly at (rather than above) a minimum IFR altitude is MDA when weather
conditions require; otherwise, leave a healthy safety margin. Of
course, you'll have a hard time convincing a flight test examiner of
this, but in real life, it makes sense to me -- my plane is a lot
slower and can descend at a lot steeper angle than a big airliner, so
I don't need a long, shallow approach slope anyway.

I don't know if this would be considered "a healthy safety margin", but my
examiner said the same thing that my instructor did - that the PTS says
+100 feet/-0 feet, so you should always fly 50 feet high to give yourself
a bit of a buffer.


--
Paul Tomblin http://xcski.com/blogs/pt/
Pascal - A programming language named after a man who would turn over in his
grave if he knew about it.

I didn't say it was a smart move (:-).

Bob

"David Megginson" wrote in message
...
"Bob Gardner" writes:

When I was an examiner, I would have expected you to fly the approach
profile as published. Once upon a time I decided to forego the "descent
and
maintain 2200 feet" on the way in to BFI's ILS 13R, thinking that I
would
stay at 3000 and intercept the glideslope high....got chided by Seattle
Approach for doing so.

But in that case, if I understand correctly, you had a specific
instruction from ATC to descend to 2200 -- that's different from
step-down altitudes in a published IAP.


All the best,


David

"Roy Smith" wrote in message
...

The examiner probably will, and might ding you on it if you didn't
explain why you were high. It sounds like you've got a perfectly good
plan, however, and I suspect most examiners would be impressed with
the level of pre-flight planning you put into this if you explained it
ahead of time.

Let me guess. Rather than preflight planning, this question sprouted from
repeated attempts to pass the instrument check ride in Microsoft's Flight
Simulator!

Know this approach well. Must've flown in a hundred times trying to pass
that stupid "check ride".

If you're flying the approach IRL, my apologies for kidding around.

-Scott

On Thu, 16 Oct 2003 20:13:36 GMT, "Bob Gardner" wrote:

When I was an examiner, I would have expected you to fly the approach
profile as published. Once upon a time I decided to forego the "descent and
maintain 2200 feet" on the way in to BFI's ILS 13R, thinking that I would
stay at 3000 and intercept the glideslope high....got chided by Seattle
Approach for doing so. Over the years I have learned that ATC expects you to
do the expected.

Bob,

Here at the other end of the country, I routinely stay at my assigned
altitude until intercepting the GP. ATC doesn't care, nor does an FAA
examiner with whom I've ridden several times.

HOWEVER, my clearance is NOT descend and maintain 2200' ... Rather, I
might be at 3000', and my clearance might be something like "maintain at or
above 1800' until established; cleared for the ILS 14 approach".

If I received a clearance that said "descend and maintain 2200', cleared
for the approach" I would treat that as an altitude assignment, and descend
to 2200' expeditiously.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Bob Gardner wrote:

When I was an examiner, I would have expected you to fly the approach
profile as published. Once upon a time I decided to forego the "descent and
maintain 2200 feet" on the way in to BFI's ILS 13R, thinking that I would
stay at 3000 and intercept the glideslope high....got chided by Seattle
Approach for doing so. Over the years I have learned that ATC expects you to
do the expected.

The industry has worked hard to get away from dive-and-drive. A constant
descent profile is a lot safer, provided it doesn't bust a stepdown. If a
stepdown is mandatory it will so state on the Jepp chart, and have a line above,
as well below, the altitude on the NACO chart.