SDF?

Im new to IFR and was wondering what an SDF approach is.

Thanks!

Tlewis95 wrote:
Im new to IFR and was wondering what an SDF approach is.

Thanks!

The AIM is your friend. If you are a pilot, you should have one.
It's in chapter 1-1-10. A SDF (Simplified Directional
Facility) essentially a localizer type facility but it has a wider
(6 or 12 degree) course width. It also might not be aligned with
the runway. I can't recall ever actually seeing one in real life,
but I'm sure people will pipe up with their favorites.

This is different from an LDA, which is a localizer that just isn't
aligned with a runway. We've got an LDA here into National Airport.
It even has a glide slope, it just doesn't take you anywhere near
the airport.

In article ,
says...

Im new to IFR and was wondering what an SDF approach is.


Look it up in any book, and you'll find probably a full paragraph, indicating
the amount of printing ink the publishers wish to squander on this approach -
the SDF (Simplified Directional Facility, IIRC) is like a LOC approach, except
instead of being aligned with a friendly runway it's aligned with a big old
tree or communications antenna several degrees off the extended centerline.
Lateral precision is reduced, compared with a LOC, and MDA is correspondingly
higher.

There are very few of them left - SME (Somerset KY) was one of them, until a
KingAir took out a communications tower a few years back.

I think you can pretty much bank on them being phased out entirely pretty
soon, though I wouldn't want to put a time scale on that.

G Faris

"Ron Natalie" wrote in message =
m...
Tlewis95 wrote:
Im new to IFR and was wondering what an SDF approach is.
=20
Thanks!
=20
The AIM is your friend. If you are a pilot, you should have one.
=20

And even if you don't have one, you still can read it on the web.
http://www.faa.gov/ATPubs/AIM/index.htm
---JRC---

G Farris wrote:


Look it up in any book, and you'll find probably a full paragraph, indicating
the amount of printing ink the publishers wish to squander on this approach -
the SDF (Simplified Directional Facility, IIRC) is like a LOC approach, except
instead of being aligned with a friendly runway it's aligned with a big old
tree or communications antenna several degrees off the extended centerline.
Lateral precision is reduced, compared with a LOC, and MDA is correspondingly
higher.

The above is the definition of an LDA.

In article ,
says...

G Farris wrote:


Look it up in any book, and you'll find probably a full paragraph,
indicating
the amount of printing ink the publishers wish to squander on this approach
-
the SDF (Simplified Directional Facility, IIRC) is like a LOC approach,
except
instead of being aligned with a friendly runway it's aligned with a big old
tree or communications antenna several degrees off the extended centerline.
Lateral precision is reduced, compared with a LOC, and MDA is
correspondingly
higher.


The above is the definition of an LDA.

Well, no. The LDA has the same characteristics as a localizer, but is not
aligned with the runway. The SDF has reduced lateral precision, and may not be
aligned with the runway.

G Faris

For all practical purposes, you can treat the LDA and SDF as a poorly
designed Localizer approach. LDA is not aligned with the runway, and
SDF may or may be aligned and has a larger course width. Here are some
examples: LDA/DME-18 @ TVL, LDA-C @ VNY, SDF10 @ DWU



(Tlewis95) wrote in message ...
Im new to IFR and was wondering what an SDF approach is.

Thanks!

I have shot many SDF approaches. The difference is it's either 6 or 12
degrees and you don't know which. As long as the needle is in the center it
doesn't matter. Usually you are aligned with the runway, but it may not
align you with the runway, as are some ILS approaches. There is NOTHING
wrong with these approaches.

"Andrew Sarangan" wrote in message
om...
For all practical purposes, you can treat the LDA and SDF as a poorly
designed Localizer approach. LDA is not aligned with the runway, and
SDF may or may be aligned and has a larger course width. Here are some
examples: LDA/DME-18 @ TVL, LDA-C @ VNY, SDF10 @ DWU



(Tlewis95) wrote in message
...
Im new to IFR and was wondering what an SDF approach is.

Thanks!

DH wrote:
I have shot many SDF approaches. The difference is it's either 6 or 12
degrees and you don't know which.

Of course you don't know what the angular course width of a real localizer
is either, but it's going to be narrower than 6 degrees.

"Ron Natalie" wrote in message
m...
DH wrote:
I have shot many SDF approaches. The difference is it's either 6 or 12
degrees and you don't know which.

Of course you don't know what the angular course width of a real localizer
is either, but it's going to be narrower than 6 degrees.

To be picky; it will be 6 degrees or less, down to a minimum of 3 degrees.

And if you really want to know what the course width is, you can look it up
(along with every other bit of data) at the FAA flight inspection (AVN) web
site:

http://avnwww.jccbi.gov/datasheet/