HVN VOR-A -- why such a high MDA?

The VOR-A at New Haven
(http://www.myairplane.com/databases/...s/00671VG2.PDF) has an
MDA of 720, which is about 300 feet higher than the towers in the area.
The VOR-2
(http://www.myairplane.com/databases/...s/00671VG2.PDF) gets
you down to 380, and has to deal with the same towers. Why does it get
to have an MDA 340 feet lower than the VOR-A?

In fact, the VOR-A is almost perfectly lined up with runway 32; I don't
see why it couldn't have been the VOR-32 with an MDA about 300 feet
lower. Any of you TERPs-heads out there understand what's going on here?

"Roy Smith" wrote in message
...

The VOR-A at New Haven
(http://www.myairplane.com/databases/...s/00671VG2.PDF) has an
MDA of 720, which is about 300 feet higher than the towers in the area.
The VOR-2
(http://www.myairplane.com/databases/...s/00671VG2.PDF) gets
you down to 380, and has to deal with the same towers. Why does it get
to have an MDA 340 feet lower than the VOR-A?

In fact, the VOR-A is almost perfectly lined up with runway 32; I don't
see why it couldn't have been the VOR-32 with an MDA about 300 feet
lower. Any of you TERPs-heads out there understand what's going on here?


Apples and oranges. You're comparing the straight-in MDA of the VOR RWY 2
to the MDA of the VOR-A. The VOR-A has only a circling MDA, which is 720
feet, the same as the circling MDA of the VOR RWY 2.

In article k.net,
"Steven P. McNicoll" wrote:

"Roy Smith" wrote in message
...

The VOR-A at New Haven
(http://www.myairplane.com/databases/...s/00671VG2.PDF) has an
MDA of 720, which is about 300 feet higher than the towers in the area.
The VOR-2
(http://www.myairplane.com/databases/...s/00671VG2.PDF) gets
you down to 380, and has to deal with the same towers. Why does it get
to have an MDA 340 feet lower than the VOR-A?

In fact, the VOR-A is almost perfectly lined up with runway 32; I don't
see why it couldn't have been the VOR-32 with an MDA about 300 feet
lower. Any of you TERPs-heads out there understand what's going on here?


Apples and oranges. You're comparing the straight-in MDA of the VOR RWY 2
to the MDA of the VOR-A. The VOR-A has only a circling MDA, which is 720
feet, the same as the circling MDA of the VOR RWY 2.

Yeah, but the point of my question was, "Why didn't they publish
straight-in minimums for the VOR-A and call it the VOR-32?"

"Roy Smith" wrote in message
...

Apples and oranges. You're comparing the straight-in MDA of the VOR RWY
2
to the MDA of the VOR-A. The VOR-A has only a circling MDA, which is 720
feet, the same as the circling MDA of the VOR RWY 2.


Yeah, but the point of my question was, "Why didn't they publish
straight-in minimums for the VOR-A and call it the VOR-32?"


I don't know, I'm no TERPS expert, but I'd wager it's because the MAP is
beyond the runway 32 threshold.

"Steven P. McNicoll" wrote in
link.net:


"Roy Smith" wrote in message
...

Apples and oranges. You're comparing the straight-in MDA of the VOR
RWY 2
to the MDA of the VOR-A. The VOR-A has only a circling MDA, which
is 720 feet, the same as the circling MDA of the VOR RWY 2.


Yeah, but the point of my question was, "Why didn't they publish
straight-in minimums for the VOR-A and call it the VOR-32?"


I don't know, I'm no TERPS expert, but I'd wager it's because the MAP
is beyond the runway 32 threshold.




But there are straight-in approaches with the MAP well past the runway
threshold. Look at VOR24@RID for example.

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On Sat, 30 Oct 2004 19:34:19 -0400, Roy Smith wrote:

The VOR-A at New Haven
(http://www.myairplane.com/databases/...s/00671VG2.PDF) has an
MDA of 720, which is about 300 feet higher than the towers in the area.
The VOR-2
(http://www.myairplane.com/databases/...s/00671VG2.PDF) gets
you down to 380, and has to deal with the same towers. Why does it get
to have an MDA 340 feet lower than the VOR-A?

In fact, the VOR-A is almost perfectly lined up with runway 32; I don't
see why it couldn't have been the VOR-32 with an MDA about 300 feet
lower. Any of you TERPs-heads out there understand what's going on here?

I'm not sure, but I wonder if it has something to do with the Missed
Approach path. The MA segment for the VOR-A seems to come a lot closer to
the 400+' towers than does the MA segment for the VOR-2.


--ron

In fact, the VOR-A is almost perfectly lined up with runway 32;

In addition to the runway alignment issue, there are two other
criteria used for issuing straight in minimums: descent gradients
cannot exceed 400 ft/nm and the course must intersect the runway
center line within a certain distance of the of the runway threshold,
3000-5200 ft in this instance.

The descent gradients seem OK here, so my guess would be the point of
course intersection was out of tolerance.

There are three requirements that must be met to establish straight-in
minimums:

1. Final approach course alignment with runway.

2. Descent gradient

3. Limits on where final approach course crosses or parallels the runway
centerline, extended.

Number 3 is impossible to assess without the source data.

Finally, flight inspection can nix the straight-in minimums if they don't
like the way the approach flies.

Roy Smith wrote:

The VOR-A at New Haven
(http://www.myairplane.com/databases/...s/00671VG2.PDF) has an
MDA of 720, which is about 300 feet higher than the towers in the area.
The VOR-2
(http://www.myairplane.com/databases/...s/00671VG2.PDF) gets
you down to 380, and has to deal with the same towers. Why does it get
to have an MDA 340 feet lower than the VOR-A?

In fact, the VOR-A is almost perfectly lined up with runway 32; I don't
see why it couldn't have been the VOR-32 with an MDA about 300 feet
lower. Any of you TERPs-heads out there understand what's going on here?

In article ,
Greg Esres wrote:

In fact, the VOR-A is almost perfectly lined up with runway 32;

In addition to the runway alignment issue, there are two other
criteria used for issuing straight in minimums: descent gradients
cannot exceed 400 ft/nm and the course must intersect the runway
center line within a certain distance of the of the runway threshold,
3000-5200 ft in this instance.

The descent gradients seem OK here, so my guess would be the point of
course intersection was out of tolerance.

The FAC is based on a VOR radial; by picking a radial up or down a
couple of degrees, they can make the FAC intersect the extended
centerline anywhere they want. The approach is over water and the VOR
is on the field, so neither terrain or signal quality should be an issue
for which radial they use.

"Andrew Sarangan" wrote in message
...

But there are straight-in approaches with the MAP well past the runway
threshold. Look at VOR24@RID for example.


Interesting. One wonders why this isn't a VOR-A approach.