IFR alternate

[Liquid Charlie]

At the end of the day what is in the forecast is just an advisory - you have to make the choice on what you feel comfortable with. My first rule of thumb -- don't ever believe a forecast -- if you are picking pepper out of fly shit just to make an alternate work -- that ain't no alternate --

We all use "paper" alternates from time to time but day that going to an alternate is a real possibility -- make the choice a good one

[swordfish]

My first rule of thumb -- don't ever believe a forecast -- if you are picking pepper out of fly shit just to make an alternate work -- that ain't no alternate --
We all use "paper" alternates from time to time but day that going to an alternate is a real possibility -- make the choice a good one

+1

Exactly my sentiments, which is why I caution people against depending on "PROBs".

[swordfish]

The disabled aircraft scenario is not that unlikely. It happens quite frequently that a runway will become unusable for any reason. There are some risks we accept. Is accepting lower alternate minima an acceptable risk when we can mitigate it otherwise

That depends on your availability of alternates. Try preaching that to any of the pilots in the Baffin, where an alternate for Frobisher Bay is "not unusually" 180 nm away, and other "possible" alternates work on paper, rather than reality.

I have been flying professionally in Canada since 1974, and have about 20,000 hours. In that time, I've gone to an alternate only a handful of times; and of those times, it was never selected on single or dual ILS availability; it was never selected because a PROB period in the TAF (or FT as it used to be called) permitted its consideration; and of the times I went to alternates, I have never been faced with a runway closure, or held up because of a disabled aircraft.

The statistical probability therefore remains LOW, and it is a risk I will continue to accept rather than mitigate.

As Liquid Charlie implies, if there's a real possibility of having to go to an alternate, don't take off.

[x-wind]

From tc.gc.ca

What is a Reduced Visibility Operations Plan (RVOP)?

It is a plan that calls for specific procedures established by the aerodrome operator and/or ATC when aerodrome visibility is below RVR 2600 (½ SM) down to and including RVR 1200 (¼ SM).

What is a Low Visibility Operations Plan (LVOP)?

LVOP (Low Visibility Operations Plan) means a plan that calls for specific procedures established by the aerodrome operator and/or ATC when aerodrome visibility is below RVR 1200 (¼ SM).

------------------------

The landing minima has nothing to do with RVOP or LVOP.

Concerning a PROB period it is the landing minima that is to be referenced, this is not an interpretation as it says "landing minimum" and landing minima has a definition.

[Big Pistons Forever]

LC and Swordfish

A huge + 1 . This obsession with regulatory minutia so prevalent in the flight schools is what happens when you get instructors who have never flown a real IFR flight in their lives. Yes you have to know the rules to pass the exam and keep the paperwork legal but all the real world PDM doesn't involve knowing the alternate rules it involves applying the alternate rules. Central to that IMO is understading what is the dominate weather pattern and what is it doing. For example I once did a trip in a Navajo from Vancouver to Victoria one October. Takeoff was about 45 min before sunset and it was foggy. YYJ was 200 and 3/4 and the YVR TAF was 400 and 1. I filed VYR as the alternate and told the boss I was taking enough gas to get to Calgary in case everything crashed when the sun set. We just made it in to YYJ and as soon as the sun set YVR went Cat 2 and so did pretty much everywhere else including all the Okanogan valley airports......

This is why I rant on and on about finding a MEIFR Instructor with real line flying IFR experience who can provide some real world context the rules.

[x-wind]

I had a similar experience that I referred to earlier although I was going YVR and YYJ was to be my alternate. Except I didn't go. I like the local weather manuals found here:

http://www.navcanada.ca/ContentDefiniti ... -BC31E.PDF

If you're insinuating that I've an obsession with regulatory minutia, I don't take offence. Its good to know the rules to the level of complication that they are for a multitude of reasons. For the record I'm not a practising instructor and do a lot of IFR flying in the left seat.

[swordfish]

X-Wind:

I am aware of what the definitions are...of course.

The IMPLICATIONS of the definitions are what you are faced with. For example, if the visibility is actually below the minima for the approach, you are then obliged to refer to the Approach Ban portion of the regs - or for easy reference, CAP Gen.

If the vis is below the Approach Ban specs (or the approach minima), then you are obliged to refer to the RVOP/LVOP to see if you can even maneuver on the airport!

The visibility IS limiting these days. It doesn't actually say so anywhere, but the above documents set limits as to what you can and cannot do. They don't talk about ceilings at all...they are only concerned with vis.

Ok...you squeak in to Armpit Ontario (which has your standard ILS and RVOP in effect) in 3/8 mile, RVR 1500, feeling pretty good with yourself after seeing the little points of approach lighting beaming up at you with their 'welcome home' invitation, taxi to the terminal, and you're 'asked' to call the tower. You get CADORSd for landing below ½ mile, you get violated by TC for continuing the approach past the FAF, and you get violated by the airport authority for taxiing off the runway.

Now...tell me again that visibility wasn't a limiting factor...? ...hello....?

[Big Pistons Forever]

X wind. Sorry if my post came accross as throwing rocks at you. My intent was a more general comment on the tendancies of many MEIFR flight schools to spend a great deal of training time on regulatory minutia but hardly any on to the application of common sense. Dealing with a Comm failure is another example of how flight schools make a meal out of a fundamentally praticale exercise in using common sense.

[x-wind]

I was merely correcting your incorrect example. I didn't tell you anything, it was a quote that was in the context of the terms and numbers you used previous to this rant.

Cheers,

Edited:
No worries to BPF or Swordfish.

[swordfish]

I think I'm getting off-topic ...no intent to hijack the thread, but it's easy to get diverted with related stuff...

I am now returning to my cubicle.

[RichAir]

While looking for an other topic, I felt on this one.
Let me help you not to speculate on alternate guys. I was thinking the same as you do:
You can't use an airport as an alternate if the BASE TAF is BELOW alternate minimas, when a TEMPO period exists within the ETA to this airport, where that TEMPO has HIGHER than alternate minimums weather. (eg. 200-1 TEMPO BKN020-6). It made sense in my head. One day I argued with a collegue that my interpretation of the CARs was the right one on this. We didn't agree at the end.
So I wrote Transport Canada to clarify that and change how it is written as it can be interpreted wrong by some.
Here's basically the answer of TC:
TC told me I was wrong, that you can use an alternate legally which is like the example above. TC also says that despite it could be legal, it could lead to an operational safety issue of the flight. Here's the example they use:

17:00Z: TAF 30012KT 1SM OVC001 TEMPO 2915/2920 3SM BKN010

This being said now, TC didn't tell me they were going to do any modification to this, despite a grey zone that could lead some wreckless pilots to file that kind of alternate mentionned above.

The same applies to PROB, but with the landing minima thing.
So, if your wannabe alternate is unusable because it's 500-2 for a one precision approach only, you just have to add a PROB30 300-1/2 and it's now legal.

I KNOW IT DOESN'T MAKE SENSE AT ALL BUT IT'S THE WAY IT IS. SOME CALL IT NATURAL SELECTION.

[swordfish]

You CANNOT use the airport as an alternate unless the TAF for your ETA permits it. If there is a TEMPO period in there, if it's lower than what is required (for example, 600/2) you cannot use it if your ETA will be in that TEMPO period. (If it's higher, you don't need to consider it).

If you're going to look at the PROB forecast, it may be lower than the alternate limit, but not lower than the landing limits. However, the rest of the TAF must support the use of the airport as an alternate!

i.e. you can't have a forecast lower than what's required to use it as an alternate (e.g. 700/2) during the period, and then go ahead and use it as an alternate because the PROB has landing limits (or better).

[RichAir]

Swordfish, it comes directly from Transport Canada in Ottawa. If you want to tell them they are wrong in the interpretation of what they wrote themselves, you may try to convince them. Good luck

[swordfish]

Yeah...you'd better give me their number, and I'll give 'em a call & straighten them out. You can't use that TAF in your example as an alternate, with the following assumptions:

The TEMPO period is no more than 50% of the whole period.
The TEMPO is within the forecast period (the period of the forecast is not actually specified).
Your ETA is anywhere in the forecast period.

And you most certainly cannot use it if a PROB period gives you landing minima or higher, for your ETA, while the rest of the TAF (the "base" part, as everyone seems to refer to it as) is below the required alternate minima, which it certainly IS in your example.

[sakism]

No pilot-in-command of an aircraft shall include an alternate aerodrome in an IFR flight plan or IFR flight itinerary unless available weather information indicates that the ceiling and ground visibility at the alternate aerodrome will, at the expected time of arrival, be at or above the alternate aerodrome weather minima criteria specified in the CAP. (CARs 602.122 and 602.123)

Aerodrome forecasts (TAF) that contain the terms BECMG, TEMPO or PROB may be used to determine the weather suitability of an aerodrome as an alternate, provided that:

(a) where conditions are forecast to improve, the forecast BECMG condition shall be considered to be applicable as of the end of the BECMG time period, and these conditions shall not be below the published alternate minima requirements for that aerodrome;

(b) where conditions are forecast to deteriorate, the forecast BECMG condition shall be considered to be applicable as of the start of the BECMG time period, and these conditions shall not be below the published alternate minima requirements for that aerodrome;

(c) the forecast TEMPO condition shall not be below the published alternate minima requirements for that aerodrome; and

(d) the forecast PROB condition shall not be below the appropriate landing minima for that aerodrome.

RichAir - if the fellow in Ottawa told you as he did - he was wrong. The above is the wording straight out of the CAPGEN and there is no room for interpretation. It's black and white.

The four bold areas of the quote say, in order:
1. The TAF has to be at or above alternate minima,
2. The TEMPO has to be at or above alternate minima,
3. AND (not OR),
4. The PROB has to be at or above landing minima.

[RichAir]

Sure there's room for interpretation as the CARs and CAP GEN doesn't tell you explicitly that the base part of the TAF, if lower than alt min, with a TEMPO period greater than mins, can't be used as an alternate. Nothing is written about the base part of the TAF, either in french or english. I agree with you, that it doesn't make sense at all, and if you follow the CARs, using a crappy base part with a good TEMPO doesn't give you the insurance that at the ETA, the ceiling and visibility will be at or above the weather minimums for alternate. That's what I answered them but nothing came back but a message he was on vacation. I was tired of this and I though changing TC was to much efforts and we should wait an accident happens as usual. Sword, check your PMs

[BTD]

Sakism is right. The person at TC was wrong. Reread his post.

There is no such thing as the "base" TAF in navcanada's world. There is only a TAF. Then any change periods. If you get rid of the "base" TAF thought. The first bolded part of Sakism's post answers your below quote.

Sure there's room for interpretation as the CARs and CAP GEN doesn't tell you explicitly that the base part of the TAF, if lower than alt min, with a TEMPO period greater than mins, can't be used as an alternate

BTD