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View Full Version : Exemption 3585


TheFly
11-23-2013, 04:50 AM
Can anyone break down this exemption in simple terms? Thanks.


Emb170man
11-23-2013, 05:24 AM
Ill give it a go.

Let's say that your destination TAF doesn't look so hot. You need 1/2sm to go there and the TAF says tempo 1/4. 3585 allows you to still dispatch there, but requires a second alternate to be listed, and fuel for the furthest alternate. The caveat is that the weather below your minimums must be at least 50% of what you need, and must be part of a conditional statement in the TAF (part of a prob30, prob40 or tempo line). Same can be done if your first alt is below the derived alternate mins, same rules apply ( conditional and 50%). 2nd alternate has to meet all weather mins.

That's about as simple as I can make it, anyone else have a better means of making it clear as mud?

bhmdiversion
11-23-2013, 05:42 AM
Half Half Full is the term we use in OCC if for some reason were dispatching 3585. Emb170man had it pretty close.


BoilerUP
11-23-2013, 05:47 AM
Can anyone break down this exemption in simple terms? Thanks.

It means "You're effing going!"

rickair7777
11-23-2013, 06:25 AM
Conditional language = PROB or TEMP. We used to consider BCMG as a conditional term but no more apparently (not sure if that's just us, or the FAA).

You can go if:

1. DEST VIS Cond. Lang. >= 1/2 of that required for the approach. Also CIG >= 1/2 required only if CIG is a published requirement in the approach (not the norm).

AND

2. 1ST ALT VIS & CIG Cond. Lang. >= 1/2 of that required for the approach. Required CIG in this case, if not published, would be the MDA/DH.

AND

3. 2ND ALT VIS & CIG >= normal minimums (2ND ALT is always required for 3585 at least for us).

In all cases main body language must meet mins.

snippercr
11-23-2013, 08:54 AM
If you can then combine 3585 with 1nav/2nav at some example airports to determine exactly WHAT your minimums at that airport have to be, you are golden!

Cubdriver
11-23-2013, 09:54 AM
This rule is a pita and it is rarely used. Most pilots kind of hate it, but knowing the history helps a bit. It was an exemption granted originally to Peoples Express to normal FAA weather rules helping them compete with mainline companies who had more expensive weather departments and their own certified WX reports. The mainlines would get to fly when the same Peoples Express flights had to sit around waiting for NWS updates. It was a way to level the playing field a little bit, making conditional remarks being somewhat vague by nature, less restrictive and less confining for those who cannot afford independent WX reports. Richie Lengel's book also has a good explanation.

John Carr
11-23-2013, 07:28 PM
This rule is a pita and it is rarely used. Most pilots kind of hate it, but knowing the history helps a bit. It was an exemption granted originally to Peoples Express to normal FAA weather rules helping them compete with mainline companies who had more expensive weather departments and their own certified WX reports. The mainlines would get to fly when the same Peoples Express flights had to sit around waiting for NWS updates. It was a way to level the playing field a little bit, making conditional remarks being somewhat vague by nature, less restrictive and less confining for those who cannot afford independent WX reports. Richie Lengel's book also has a good explanation.

"Back in the day", there were other methods to use as well, probably used in conjunction with 3585. Things like planned re-dispatch enroute. Also, even though some may not have been able to pay for their own WX departments, they could pay for something like a RAMTAF, etc from a private vendor. My prior company used to do both.

Even with the experience I have with 3585, as soon as I see in on the release the FIRST thing I do is pull out the FOM and read the section. It simply chews up too much of my personal memory space to memorize it. Combine that if it's a 5 am show following an RR overnight, etc.

rickair7777
11-24-2013, 06:24 AM
Conditional language = PROB or TEMP. We used to consider BCMG as a conditional term but no more apparently (not sure if that's just us, or the FAA).



To answer my own question...

Aviation Weather Services AC 00-45G Change 1 no longer includes BCMG as one of the Forecast Change Indicator Groups for TAF's. Only FM, TEMPO and PROB are used. BCMG can still be used in area forecasts, just not TAFs.

DroopsN10
12-13-2013, 07:45 PM
Good stuff here I haven't heard of before. So to really dumb is down it's a backup for your first alt if it has a TEMPO or PROB in the taf? 2nd alt has to meet all wx reqs. Also do you have to have enough fuel to get to your 2nd alternate with reserves or just enough to get to that point. Thanks!

John Carr
12-15-2013, 11:07 AM
Also do you have to have enough fuel to get to your 2nd alternate with reserves or just enough to get to that point. Thanks!

Like I said before, I don't EVER go 3585 without having my FOM open in front of me, which I don't right now.

I'll have to look, but I believe that the language of enough fuel to reach the most distant alternate + reserves still applies. Not necessarily the second alternate. I know, that sounds kind of confusing and counter intuitive. But also as mentioned, this is stuff about being able to legally dispatch flights under more extreme circumstances.

Fly Boy Knight
12-15-2013, 03:27 PM
Since it's part of my recurrent studying, here it goes.

3585 Exemption Spark Notes:

Before 3585, flights would not be able to depart for an airport if the weather is forecast to be below landing mins. This is particularly annoying when the main forecast says it'll be fine but a little CONDITIONAL part of the forecast (TEMPO/PROB) says it MIGHT be below mins. Although not likely, this conditional forecast was still limiting because it is part of the TAF.

Example: Required Landing Visibility = 1/2 SM Vis
TAF FM forecast = 1 SM
TAF TEMPO line = 1/4 SM
Without 3585, you'd not be able to depart for this airport

As posted before, People's Express got tired of this crap and pushed exemption 3585.

Exemption 3585 allows you to depart for an airport even though conditional language in the forecast says it'll be below landing mins as long as...

1. The Main Body forecast (FM line... not conditional line) is above required minimums and,

2. The conditional part of the forecast that IS below landing minimums (TEMPO / PROB) is not less than ONE HALF of the required mins (See examples below) and,

3. You file a SECOND IFR Alternate.

Example 1 (from above):
Required Landing Visibility = 1/2 SM Vis
TAF FM forecast = 1 SM
TAF TEMPO line = 1/4 SM
- You can depart for this airport using 3585 as long as you have a 2nd alternate. In this case, HALF of the required 1/2 SM visibility would be 1/4 SM visibility and since the conditional line is not LESS than 1/4 SM, you are good to go.

Example 2: Required Landing Visibility = 1 SM Vis
TAF FM forecast = 1 SM
TAF TEMPO line = 1/4 SM
- You would NOT be able to depart even with 3585 because the tempo forecast is less than 1/2 of the required visibility (half of 1 SM is 1/2 SM and since the tempo is below 1/2, 3585 cannot help you)

If you do use 3585 to depart for an airport, you must have a SECOND alternate. Your second alternate must meet the same IFR Alternate Filing mins as usual ("400 : 1" or "200 : 1/2" Rules as applicable)

When determining a DESTINATION's required weather, all that is controlling is VISIBILITY. You don't have to look at ceiling when using 3585 for your destination.

That said, you can also use 3585 when filing a (FIRST) IFR Alternate. The same conditional language/second alternate requirements apply except, since BOTH ceiling and visibility are controlling when deriving alternate minimums, you must now evaluate both ceiling and visibility.

Example 1:
Derived alternate mins for your 1st Alt: 600ft Ceiling / 2 SM Vis
TAF FM Line: 700ft / 3 SM
TAF TEMPO Line: 400ft / 1 SM
- You may use this airport as an IFR alternate using 3585 as long as you file a second alternate.

Example 2:
Derived alternate mins for your 1st Alt: 600ft Ceiling / 2 SM Vis
TAF FM Line: 700ft / 3 SM
TAF TEMPO Line: 200ft / 1/2 SM
- You may NOT use this airport as an IFR Alternate even using 3585 because the TEMPO ceiling and vis are too low (less than half of 600ft and 2 SM)

You may NOT use 3585 when trying to find a 2nd Alternate. You must find a 2nd alternate without using 3585. All elements of the forecast must be above the required alternate filing minimums.

highalt41
02-09-2014, 08:36 AM
Fly boy pretty much nailed it just remember to use half vis and half ceiling at first alt, and always have a fom handy when and if you are dispatched 3585

Airmedpilot
11-01-2017, 09:47 AM
Exemption 3585 = Can dispatch to destination below minimums, only if not less than 1/2 lowest visibility in a CONDITIONAL statement in a TAF.

First Alternate, not less than half of the alternate minimum ceiling and visibility.

Second Alternate, METAR or TAF or any combination in main body, must be above alternate minimums for ceiling and visibility.



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