Metar says wx below mins. Forecast above mins. 45 min flt

[bafanguy]

Re: Metar says wx below mins. Forecast above mins. 45 min fl

Tried to find the exact exemption but this was all I could find:




<nobr>January 28, 2009</nobr>
<nobr>U.S. Department of Transportation</nobr>
<nobr>Docket Management System</nobr>
<nobr>400 7</nobr>
<nobr>th</nobr>
<nobr>Street SW, Plaza 401</nobr>
<nobr>Washington, DC 20591-0001</nobr>
<nobr>Re: Exemption No. 3585, as amended; Docket No. FAA-2001-9379</nobr>
<nobr>Ladies/Gentlemen:</nobr>
<nobr>In accordance with Title 14 of the Code of Federal Regulations (14CFR) § 11.61, the Air Transport</nobr>
<nobr>Association of America, Inc. (ATA), on behalf of its member airlines</nobr>
<nobr>1</nobr>
<nobr>petitions the Administrator</nobr>
<nobr>for an extension of Exemption No. 3585P (Docket No. FAA-2001-9379). This exemption is</nobr>
<nobr>scheduled to expire on June 30, 2009.</nobr>
<nobr>Exemption 3585 provides relief, under certain conditions and limitations, from 14 CFR §§ 121.613,</nobr>
<nobr>121.619(a), and 121.625 to the extent necessary to: (1) dispatch an airplane, under IFR, to a</nobr>
<nobr>destination airport; and (2) list an alternate airport for that destination airport when the Aerodrome</nobr>
<nobr>Forecast (TAF) for either one or both of those airports indicates by the use of conditional language</nobr>
<nobr>such as “BECMG,” “PROB,” or “TEMPO,” in the TAF that the weather could be below authorized</nobr>
<nobr>weather minimums at the time of arrival. Dispatch under these circumstances is permitted if the</nobr>
<nobr>information contained in the main body of the TAF used by the certificate holder’s dispatch center</nobr>
<nobr>shows, for each flight to be dispatched, that the weather at the destination airport and alternate</nobr>
<nobr>airport listed in the dispatch release will be at or above authorized weather minimums at the time of</nobr>
<nobr>arrival.</nobr>
<nobr>This exemption has been used to the benefit of the traveling public for more than twenty-one</nobr>
<nobr>years, with no known compromise of safety. With regard to public interest and equivalent levels </nobr>
<nobr>of safety, the circumstances that warranted the initial grant of exemption continue to exist</nobr>

 

[jtrain609]

Re: Metar says wx below mins. Forecast above mins. 45 min fl

If the forcast (TAF) for our arrival time is better than the needed approach minimums then we can dispatch. (Even with a crappy metar. Generally an alternate is needed of course.)

We run into this scenario every once in a while during the winter with Sun Valley, Idaho. Sometimes it works and sometimes it doesn't. (Then it is off to the alternate and often the passengers get bussed to Sun Valley.) Naturally I have learned to not completely trust the TAF and always make sure I have a good solid "OUT."

BTW even if we can dispatch in the above scenario, it does not always happen. We might hold off if we don't trust the weather or if newer TAFs are due to be issued.

As a new captain I remember getting dispatched from LAX to OXR (Oxnard) with the same issue. Metar was at like 1/4 mile and forcast for arrival was at 1/2 vis. So no matter how you sliced it, it was going to be tight. Discussed it with dispatch, they wanted us to go and could legally dispatch. PAX were well briefed on the situation and we ended up holding for nearly an hour on a fix on the ILS. Despite the legal to dispatch TAF, It never went above 1/4 and we went back to LAX.


I actually needed to use 3585 this winter. I think that was the second time I have ever truly needed it. I may have saved the release somewhere. I'll have to dig it up.

That fog will sit in the valley that Oxnard and Camarillo are in for, well, a long time. I'd do training flights out that way with trainee's in the Chieftain at Amflight and it was interesting at times. The worst part was how inaccurate the CMA VOR is. So we'd be sitting there in the same area, doing a hold that's only a few miles away from that ILS and I'd be wondering to myself, "I wonder how close we are to them there mountains...I really should have turned on my hand held GPS tonight..."

 

[seagull]

Re: Metar says wx below mins. Forecast above mins. 45 min fl

The regulation specifically states "weather reports or forecasts, or any combination thereof...". Not sure where the idea that "within the valid period of the METAR" came from, don't see that. Perhaps that was your particular POI's interp? The reg means what it says. You can dispatch if you believe the combination indicates above min weather (3585 aside, and, for the record, there is NOTHING wrong with that exemption, and the proof is in the record, no accidents or emergencies as a result of that exemption that I know of! The exemption just makes you carry more gas).

Sometimes the weather is great and things change and you end up with actual weather below mins. That happens. The combination of current wx and forecast is what you use. If the current wx is below mins, and the forecast is obviously missing the mark, then plan accordingly, but the regulation is written to allow for dispatch in most circumstances. It's up to you to put enough gas on so you can keep the flight safe once you dispatch under such circumstances.

 

[smig]

Re: Metar says wx below mins. Forecast above mins. 45 min fl

The regulation specifically states "weather reports or forecasts, or any combination thereof...". Not sure where the idea that "within the valid period of the METAR" came from, don't see that.

A metar is a weather report. If you are on a very short flight, and the metar is indicating weather below mins, then you don't meet the requirement that the combination of reports must meet the minimums at your ETA.

 

[casey]

Re: Metar says wx below mins. Forecast above mins. 45 min fl

A metar is a weather report. If you are on a very short flight, and the metar is indicating weather below mins, then you don't meet the requirement that the combination of reports must meet the minimums at your ETA.

that's when you get your dx to call the tower and get an RVR which trumps the metar. Or as I said earlier, forget all this nonsense and dispatch cat II as long as the airport has a cat II approach and at least 1200 RVR.

 

[Bandit_Driver]

Re: Metar says wx below mins. Forecast above mins. 45 min fl

[FONT=Arial,Bold][FONT=Arial,Bold]THE PEOPLES EXPRESS EXEMPTION 3585<O</O
<O</O

Section 1 Exemption No. 3585 (as amended)<O</O
Dispatch to a destination when weather forecast indicates in the remark section conditionally below authorized weather minimums at the time of arrival. <O</O
<O</O


A. Purpose<O</O
This exemption allows our Company to dispatch airplanes under IFR or over the top, to a destination airport; and list an alternate airport when the weather forecast (TAF) for either the destination or first alternate, or both, indicates by the use of conditional words such as “BECMG”, “PROB40”, or “TEMPO”, in the remarks section of such reports, that the weather could be below authorized weather minimums at the time of arrival, provided the information contained in the main body of the weather reports (METAR) or forecasts (TAF) used by the Dispatch Center show for each flight to be dispatched, that the weather at the destination airport and the alternate airport for that destination airport, listed in the dispatch release, will be at or above authorized weather minimums at the time of arrival.

Note: Exemption 3585 does NOT apply for supplemental operations (charter).
<O</O

B. Conditions and Limitations<O</O
1. Insert Airline Name shall apply for and obtain approval from the FAA certificate-holding office having jurisdiction over its operations before commencing operations in accordance with this exemption.<O</O
<O</O

2. Insert Airline Name must list one additional alternate airport in the dispatch release whenever the METAR, TAF, or any combination thereof for the destination airport or first alternate airport indicate, by the use of conditional words in the remarks section of such METAR or in one or more time increments of the TAF, that the forecast weather conditions for the destination and the first alternate airport could be less than the authorized weather minimums for those airports. However, the METAR or TAF must indicate in another time increment that the weather conditions for the destination, first alternate and second alternate airports are forecast to be not less than the applicable authorized weather minimum values as follows:<O</O
<O</O

a. With respect to the destination airport, the forecast weather conditions, must be not less than one-half of the lowest weather minimum visibility value established for the instrument approach procedure expected to be used for an instrument approach at the destination;<O</O
<O
b. With respect to the first alternate airport, the forecast weather conditions must be not less than one-half of the alternate weather minimum ceiling and visibility values specified in the certificate holder’s Operations Specifications for that airport; and<O</O
<O</O

c. With respect to the second alternate airport listed in the dispatch release pursuant to this exemption, the METAR, the appropriate time increment of the TAF, or any combination thereof for that airport must indicate in the main body and remarks section of the METAR or TAF that the forecast weather conditions will be at or above the alternate airport weather minimum ceiling and visibility values specified in the certificate holder’s Operations Specifications for that airport.<O</O
<O</O

3. No person may dispatch or take off an aircraft, when operating under this exemption, unless it has enough fuel:<O</O
<O</O

a. To fly to the airport to which it is dispatched;<O</O
<O</O

b. Thereafter, to fly to and land at the most distant alternate airport for the airport to which dispatched, taking into account the anticipated air traffic control routing; and<O</O
<O</O

c. Thereafter, to fly for 45 minutes at normal cruising fuel consumption.<O</O
<O</O

4. Each pilot-in-command, while en route, must ensure by way of air-to-ground communication with the Dispatch Center and other appropriate facilities, that the pilot is receiving the most current METAR and TAF for the destination airport and the alternate airports. This current weather information must be used when making a decision to proceed to an alternate airport for landing.<O</O
<O</O

5. Each BECMG change indicator in the TAF that is “deteriorating” must be considered valid at the first minute of the becoming period. Each BECMG change indicator in the TAF that is “improving” will not be valid until the last minute of the becoming period of the TAF.<O</O
[/FONT][/FONT]

 

[seagull]

Re: Metar says wx below mins. Forecast above mins. 45 min fl

A metar is a weather report. If you are on a very short flight, and the metar is indicating weather below mins, then you don't meet the requirement that the combination of reports must meet the minimums at your ETA.

That is an interp that has no basis in case law or in FAA legal interps for the AGC. It is not a bad way to interp the reg, but it would be incorrect to promote that as an official FAA position. I would agree it is defensible, but then, so are several other methodologies. None of which matters unless you bend metal.

 

[Lee D]

Re: Metar says wx below mins. Forecast above mins. 45 min fl

That is an interp that has no basis in case law or in FAA legal interps for the AGC. It is not a bad way to interp the reg, but it would be incorrect to promote that as an official FAA position. I would agree it is defensible, but then, so are several other methodologies. None of which matters unless you bend metal.

I've been on vacation for a few days or I would have responded sooner. . . .(W/o my computer, which BTW is a great way to keep the wife happy. )

Anyway seagull's posts in this thread are more or less the understanding we use. And we do dispatch sometimes with crappy METARs. Yes there is some legal interpratation to it. Essentially in the available legal opinions, current weather (the METAR,) at the destination is not mentioned even though the regs use the phrase "reports, forecasts or any combination." So the forcast is considered controlling with regard to dispatch.

So we are legal to dispatch in the personal scenario I listed above. (Which is essentially the same as your initial scenario Smig.) Worst case you dispatch, and the weather does not live up to the forecast used. You might hold, see if it gets better and then go to the alternate if it does not. In such a scenario there will always be an alternate and the Metar is going to be used as a consideration too. This is not to say that in every case where the METAR is below mins and the forecast at arrival is barely above, we go. Sometimes we may not if the PIC and dispatcher, with all the available info, feel the odds of a successful arrival are slim. (VS a divert.)