Alternate minimums same as forecast weather

Does anyone consider it somewhat dangerous that at your alternate
airport, the weather can be forecast to be as low as your alternate
minimums? Seems the potential for problems.

For example, using Carlsad California CRQ as the planned alternate,
where the VOR-A is the approach you plan to fly if necessary (assume
the ils is out). For a cat C aircraft, the alternate minimums are
1000 and 3. The approach minimums are 972 feet height above airfield,
and 3 miles without dme.

So is this all ok?

Stan

wrote:
Does anyone consider it somewhat dangerous that at your alternate
airport, the weather can be forecast to be as low as your alternate
minimums? Seems the potential for problems.

There are lots of stupidities in the alternate rules. For example,
there's no requirement that your alternate "make sense".

Around here, BDR and HVN are about 10 miles apart, both right on the
edge of the water. What's happening at one weather-wise is pretty
much guaranteed to be happening at the other. Yet, it's perfectly
legal for me to file IFR to one and use the other as my alternate.
Legal, but pointless.

When I'm picking an alternate, my goal is to find someplace that I'm
damned sure I can get into if my destination goes down. That implies
a much more conservative approach than just meeting the letter of the
law.

On Wed, 06 Apr 2005 15:33:21 GMT, wrote:

Does anyone consider it somewhat dangerous that at your alternate
airport, the weather can be forecast to be as low as your alternate
minimums? Seems the potential for problems.

For example, using Carlsad California CRQ as the planned alternate,
where the VOR-A is the approach you plan to fly if necessary (assume
the ils is out). For a cat C aircraft, the alternate minimums are
1000 and 3. The approach minimums are 972 feet height above airfield,
and 3 miles without dme.

So is this all ok?

Stan




How about this approach:

(a) Plan your flight to get to your destination, and then to some
other airport where you are very comfortable that you can get in,
without regard to whether it's a "legal" alternate or not. Calculate
the fuel requirement plus one hour (or maybe 2, whatever makes you
comfortable)

(b) Plan another flight using a legal alternate. Calculate the fuel
requirement plus 45 minutes.

If you cannot carry enough fuel to meet the greater of (a) or (b),
don't go.

In Canada, the alternate weather minimums are the same 600/2 and 800/2
as the US, but also 300 ft and 1 mile above the mda/dh and vis.
Whichever is greater. Your point about 2 places with the same weather
phenomena is well taken.
Stan

On 6 Apr 2005 11:49:53 -0400, (Roy Smith) wrote:


There are lots of stupidities in the alternate rules. For example,
there's no requirement that your alternate "make sense".

You are not required to go to your filed alternate if you cannot get into
your destination; ATC has no idea of what you filed as an alternate. What is
the problem??

Bob Gardner

wrote in message
...
Does anyone consider it somewhat dangerous that at your alternate
airport, the weather can be forecast to be as low as your alternate
minimums? Seems the potential for problems.

For example, using Carlsad California CRQ as the planned alternate,
where the VOR-A is the approach you plan to fly if necessary (assume
the ils is out). For a cat C aircraft, the alternate minimums are
1000 and 3. The approach minimums are 972 feet height above airfield,
and 3 miles without dme.

So is this all ok?

Stan

wrote in news:kru751l8bu0ve04b4j7gnfdqh2rk39hjlh@
4ax.com:

Does anyone consider it somewhat dangerous that at your alternate
airport, the weather can be forecast to be as low as your alternate
minimums? Seems the potential for problems.

But that's the definition of alternate minimums - the weather must be
forecast to be at least as good as the alternate minimums.

For example, using Carlsad California CRQ as the planned alternate,
where the VOR-A is the approach you plan to fly if necessary (assume
the ils is out). For a cat C aircraft, the alternate minimums are
1000 and 3. The approach minimums are 972 feet height above airfield,
and 3 miles without dme.

Why assume the ILS is out? If it's out, the alternate minimums should be
higher. If the permitted approach minimums are 972/3, then that's why
the alternate minimums are 1000/3, obviously.

So is this all ok?

Why wouldn't it be? Maybe I'm misunderstanding your question, but I
don't see a problem with any of this, just from your post, no other
information available.

--
Regards,

Stan

"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." B. Franklin

Around here, BDR and HVN are about 10 miles apart, both right on the
edge of the water. What's happening at one weather-wise is pretty
much guaranteed to be happening at the other. Yet, it's perfectly
legal for me to file IFR to one and use the other as my alternate.
Legal, but pointless.

When I'm picking an alternate, my goal is to find someplace that I'm
damned sure I can get into if my destination goes down. That implies
a much more conservative approach than just meeting the letter of the
law.

Sometimes I encounter the opposite problem - there's no real danger of being
left without a safe place to go, but it's hard to find a legal alternate
within range. This can happen in the summer when there's a slight chance of
thunderstorms over a large area. All the forecasts include something like
"TEMPO ceiling 500, visibility 1 in heavy rain showers," making them
unavailable as alternates, but since the storms are only scattered, there's
very little chance that all the airports will be unusable at the same time.

Stan, here in Canada, the forecast weather at your alternate must be
at least 300 feet and 1 mile above the approach minimums (or 600/2 or
800/2, whichever is higher). Supposedly to help ensure you can make
it in at your alternate. A kind of buffer.
I was just surprised to see that in the US, there are no such
additives.
And so, the alternate weather limits in the US can be the same as the
approach limits, in a very **FEW** cases.
CRQ was an example I found.
As an explanation to why it is only in a "few" cases, I notice in the
US that alternate weather limits must be at or above circling approach
limits too. And so, **normally** you find straight in approach limits
are less that alternate weather limits.
Canada does not have that circling minimums requirement as part of
alternate weather requirements.

On 07 Apr 2005 04:26:10 GMT, Stan Gosnell wrote:

wrote in news:kru751l8bu0ve04b4j7gnfdqh2rk39hjlh@
4ax.com:

Does anyone consider it somewhat dangerous that at your alternate
airport, the weather can be forecast to be as low as your alternate
minimums? Seems the potential for problems.

But that's the definition of alternate minimums - the weather must be
forecast to be at least as good as the alternate minimums.

For example, using Carlsad California CRQ as the planned alternate,
where the VOR-A is the approach you plan to fly if necessary (assume
the ils is out). For a cat C aircraft, the alternate minimums are
1000 and 3. The approach minimums are 972 feet height above airfield,
and 3 miles without dme.

Why assume the ILS is out? If it's out, the alternate minimums should be
higher. If the permitted approach minimums are 972/3, then that's why
the alternate minimums are 1000/3, obviously.

So is this all ok?

Why wouldn't it be? Maybe I'm misunderstanding your question, but I
don't see a problem with any of this, just from your post, no other
information available.

I think it's better to require the forecast weather to protect the
highest minimums published (for the procedure) than to add an arbitrary
300' buffer. It's better for the pilot to determine what kind of buffer
he would like to add, if any, than to have the government decide what
your buffer should be. Some pilots would be comfortable with no buffer,
while others may want a much higher buffer than 300 ft.
Right now the alternate minimums in the USA are determined by using a
standard value based on the type of approach being flown, or a ceiling
and visibility exceeding the highest circling minima for that
procedure/category, whichever is higher.
You can always add 300 ft to that value if you prefer, but why force it
on all other pilots?
The only time it would be dangerous is if both the primary and alternate
airports had drastic weather changes that made the field below minimums.
That could happen whether you had the USA alternate minimums, or
Canadian minimums (extra 300').
Another alternative is to pick an airport for an alternate that allows
straight in procedures for the equipment you have, that would give you
extra ceiling/vis to play with.

JPH


wrote:
Stan, here in Canada, the forecast weather at your alternate must be
at least 300 feet and 1 mile above the approach minimums (or 600/2 or
800/2, whichever is higher). Supposedly to help ensure you can make
it in at your alternate. A kind of buffer.
I was just surprised to see that in the US, there are no such
additives.
And so, the alternate weather limits in the US can be the same as the
approach limits, in a very **FEW** cases.
CRQ was an example I found.
As an explanation to why it is only in a "few" cases, I notice in the
US that alternate weather limits must be at or above circling approach
limits too. And so, **normally** you find straight in approach limits
are less that alternate weather limits.
Canada does not have that circling minimums requirement as part of
alternate weather requirements.

On 07 Apr 2005 04:26:10 GMT, Stan Gosnell wrote:


wrote in news:kru751l8bu0ve04b4j7gnfdqh2rk39hjlh@
4ax.com:


Does anyone consider it somewhat dangerous that at your alternate
airport, the weather can be forecast to be as low as your alternate
minimums? Seems the potential for problems.

But that's the definition of alternate minimums - the weather must be
forecast to be at least as good as the alternate minimums.


For example, using Carlsad California CRQ as the planned alternate,
where the VOR-A is the approach you plan to fly if necessary (assume
the ils is out). For a cat C aircraft, the alternate minimums are
1000 and 3. The approach minimums are 972 feet height above airfield,
and 3 miles without dme.

Why assume the ILS is out? If it's out, the alternate minimums should be
higher. If the permitted approach minimums are 972/3, then that's why
the alternate minimums are 1000/3, obviously.


So is this all ok?

Why wouldn't it be? Maybe I'm misunderstanding your question, but I
don't see a problem with any of this, just from your post, no other
information available.

wrote in
:

Stan, here in Canada, the forecast weather at your alternate must be
at least 300 feet and 1 mile above the approach minimums (or 600/2 or
800/2, whichever is higher). Supposedly to help ensure you can make
it in at your alternate. A kind of buffer.
I was just surprised to see that in the US, there are no such
additives.
And so, the alternate weather limits in the US can be the same as the
approach limits, in a very **FEW** cases.
CRQ was an example I found.
As an explanation to why it is only in a "few" cases, I notice in the
US that alternate weather limits must be at or above circling approach
limits too. And so, **normally** you find straight in approach limits
are less that alternate weather limits.
Canada does not have that circling minimums requirement as part of
alternate weather requirements.

In general, airports use standard alternate minimums, and the required
alternate minimums are listed on the back of the airport diagram. I must
confess that I really haven't read or worried about Part 91 alternate
minimums in a very long time, because I don't use them. My alternate
minimums are in my ops manual and ops specs. We add 200' to the
published approach minimum altitude for the approach we intend to use,
and use either 1 mile vis or published, whichever is higher, and only are
required to have 30 minutes reserve at the alternate. So for most
airports with an ILS, the alternate minimums are 400/1. As you can see,
there isn't a huge margin for error here. Fortunately, a diversion to
the alternate is rare, since we can cut the published visibility in half,
and since it's legal to descend to 100' above the TDZE with the approach
lights in sight, a miss off the ILS is seldom required, especially at
night, and I have never done one except on checkrides.

Flying a spam can for pleasure rather than profit is a very different
thing, though.

--
Regards,

Stan

"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." B. Franklin