Alternate Required

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buzzard86

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Jim R
I'm well into my instrument training and was working with a different instructor today on some knowledge prep. I know the 1-2-3 rule for requiring an alternate, but got tripped up on a question today that has me re-thinking my interpretation of how the rule is applied.

The scenario presented was something like this:

ETA: 1500Z

TAFs:
FM111400 20009KT P6SM BKN045
FM111800 27012KT P6SM OCV015

My interpretation was that I did not need an alternate because the wx 1 hour before (1400Z) and after (1600Z) my ETA was greater than 2000'/3SM (ie, it was going to be BKN045 until 1800Z). However, he said that I did need an alternate because the later TAF was below 2-3 and there was no way to know when conditions would fall below 2000 leading up to that OVC015 @ 1800Z.

I understand the logic and don't want to overthink this, but I'm sure that this will come up in my oral and I want to make sure that I can answer it correctly and confidently. Technically what's the correct answer here?
 
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buzzard86 said:
I'm well into my instrument training and was working with a different instructor today on some knowledge prep. I know the 1-2-3 rule for requiring an alternate, but got tripped up on a question today that has me re-thinking my interpretation of how the rule is applied.

The scenario presented was something like this:

ETA: 1500Z

TAFs:
FM111400 20009KT P6SM BKN045
FM111800 27012KT P6SM OCV015

My interpretation was that I did not need an alternate because the wx 1 hour before (1400Z) and after (1600Z) my ETA was greater than 2000'/3SM (ie, it was going to be BKN045 until 1800Z). However, he said that I did need an alternate because the later TAF was below 2-3 and there was no way to know when conditions would fall below 2000 leading up to that OVC015 @ 1800Z.

I understand the logic and don't want to overthink this, but I'm sure that this will come up in my oral and I want to make sure that I can answer it correctly and confidently. Technically what's the correct answer here?
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1 hour before through 1 hour after. Which TAF applies? Not the 1800 TAF. You're right, your instructor is making stuff up. Not unusual for instructors.
 
With your instructors thinks, we alway need an alternate.
 
No alternate needed based on this scenario.
 
Alternate not legally required based on the TAF provided in your scenario.
 
Thanks guys, he kind of turned the question around on me. I guess his logic was that if that second TAF was also >2000 then it's a non-issue and no alternate, but since I couldn't say with certainty that the ceiling would not drop below 2000 within my timeframe then I needed the alternate. Conceptually it kind of made sense and I think in the real world it would probably be prudent to consider an alternate in this scenario, but I appreciate the confirmation that the way I'd learned and answered it was correct.
 
buzzard86 said:
Thanks guys, he kind of turned the question around on me. I guess his logic was that if that second TAF was also >2000 then it's a non-issue and no alternate, but since I couldn't say with certainty that the ceiling would not drop below 2000 within my timeframe then I needed the alternate. Conceptually it kind of made sense and I think in the real world it would probably be prudent to consider an alternate in this scenario, but I appreciate the confirmation that the way I'd learned and answered it was correct.
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It's always prudent to consider your alternatives, but from a legal perspective, the way a TAF works is you're expected to have the weather conditions for the time period for the duration of the forecast period.
 
This is interesting to me, too. I am also an IR student and was wondering about this the other day. Y'all validated what I thought - legally the valid TAF shows a ceiling of 4500 until 1800 - outside the one hour after time limit for requiring an alternate. (I would still look at alternates given this TAF, from a practical standpoint).

Maybe this is off topic, but I am still confused about how to employ the 1-2-3 rule for airports with no terminal forecast. The class D I fly out of doesn't have a TAF (Dulles is close by, though). And please don't poke at my CFII or my training to date... I am only two lessons in at this point and mostly absorbing as much as I can read - we haven't covered this yet.

So if anyone can give me a practical explanation of how to apply the 1-2-3 rule to airports with no TAF, I would really appreciate it!
 
Deelee said:
This is interesting to me, too. I am also an IR student and was wondering about this the other day. Y'all validated what I thought - legally the valid TAF shows a ceiling of 4500 until 1800 - outside the one hour after time limit for requiring an alternate. (I would still look at alternates given this TAF, from a practical standpoint).

Maybe this is off topic, but I am still confused about how to employ the 1-2-3 rule for airports with no terminal forecast. The class D I fly out of doesn't have a TAF (Dulles is close by, though). And please don't poke at my CFII or my training to date... I am only two lessons in at this point and mostly absorbing as much as I can read - we haven't covered this yet.

So if anyone can give me a practical explanation of how to apply the 1-2-3 rule to airports with no TAF, I would really appreciate it!
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Look for the nearest TAFs. And if it gets really difficult to determine, plan an alternate anyway. The entire purpose of this regulation is to make sure you have fuel if the weather gets in the way. Unless you are extremely weight limited, or the nearest suitable alternate is a long ways away, a little extra fuel isn't going to hurt.
 
You could potentially argue that, using interpolation, the forecast could be a 3000’ ceiling at 1600, & you don’t need an alternate, assuming the destination apt has an IAP.
 
Here's my question. Did he say an alternate was legally required because "there was no way to know when conditions would fall" or planning an alternate was good risk management in this scenario because "there was no way to know when conditions would fall"?

With the increased emphasis on risk factor recognition and management, I would not be surprised to see this type of confusion between "required" and "good idea" on the part of teacher or student.

I'd say a clarifying conversation with your CFI is in order.
 
He said you would need an alternate. The real question would be to him... What does "need" actually mean. Legally vs safest choice.
If he said legally, technically he's wrong. If he says it's the safest choice, then most here (as you can see) would agree I think.
 
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Deelee said:
This is interesting to me, too. I am also an IR student and was wondering about this the other day. Y'all validated what I thought - legally the valid TAF shows a ceiling of 4500 until 1800 - outside the one hour after time limit for requiring an alternate. (I would still look at alternates given this TAF, from a practical standpoint).

Maybe this is off topic, but I am still confused about how to employ the 1-2-3 rule for airports with no terminal forecast. The class D I fly out of doesn't have a TAF (Dulles is close by, though). And please don't poke at my CFII or my training to date... I am only two lessons in at this point and mostly absorbing as much as I can read - we haven't covered this yet.

So if anyone can give me a practical explanation of how to apply the 1-2-3 rule to airports with no TAF, I would really appreciate it!
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Take a step back. The regulation says nothing about TAFs or any specific weather product. It says:

Appropriate weather reports or weather forecasts, or a combination of them​

So the practical answer is "appropriate." A TAF is the obvious answer for an airport which has them. For one which doesn't, the FA used to be the primary tool but with that gone, the most "official" is the AWC GFA Tool) in combination with nearby TAFs.
 
midlifeflyer said:
With the increased emphasis on risk factor recognition and management, I would not be surprised to see this type of confusion between "required" and "good idea" on the part of teacher or student.
Click to expand...

Mark, I think you are probably spot on here.

A little more context - I've been plugging away at the IR, have the requirements met and was close to starting check ride prep. Unfortunately my CFII just left so I'm in limbo while I try to figure out a finish-up plan. I did an hour of ground yesterday with another instructor to refresh some of the knowledge content and keep my head in the game (I passed my written last yet). This came up in the context of that conversation.

Of note, he challenged me with this scenario because was said that he was presented with the same by a DPE with whom I may ultimately take my check ride. I suspect that the DPE's intent is to drive home risk management, but this sounds like it morphed from a "should" into a "must." The word legal wasn't used per se, but the conversation was clear that the answer was "yes" to needing an alternate.

This thread has been great. If this comes up during my oral -- which I suspect I will -- I'll be prepared to speak to both the legal answer not requiring an alternate but also the consideration and selection of an alternate as an element of conservative ADM.
 
buzzard86 said:
I'll be prepared to speak to both the legal answer not requiring an alternate but also the consideration and selection of an alternate as an element of conservative ADM.
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Whether this is the case for this specific scenario, this is where we are going. It really presents a challenge for both instructors and students. We can't rely on rote memorization of a "1-2-3" rule. It now has to be used in a scenario, with understanding, application and correlation. IMO it is a special challenge because we need to learn the rule, apply an ADM personal minimum, and understand the difference. My mental gymnastics come down to a 4-part analysis of most every rule.
  1. what is the rule?
  2. what problems it this rule trying to address?
  3. doe the generally just set a minimum standard?
  4. what will my standard be?
 
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buzzard86 said:
This thread has been great. If this comes up during my oral -- which I suspect I will -- I'll be prepared to speak to both the legal answer not requiring an alternate but also the consideration and selection of an alternate as an element of conservative ADM.
Click to expand...

I agree.
And these 'technicalities' are often what trip me up on questions, especially on written-proctored exams when you cannot ask for clarification...which I try to do when someone says "need" or "should", etc.

It can be annoying, but I always feel like I need to.. or at least should try ;)
 
And don't forget that when you are actually out there flying and go missed at your destination, there is no requirement that you MUST go to your alternate.

So have Options all the time, but make sure you file an Alternate when required.
 
Craigd31 said:
You could potentially argue that, using interpolation, the forecast could be a 3000’ ceiling at 1600, & you don’t need an alternate, assuming the destination apt has an IAP.
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You could, but you’d be wrong. The forecast isn’t calling for ceilings below 4500 feet until after 1800.

As @dmspilot said, this isn’t really about needing an alternate, it’s about reading and understanding TAFs.
 
MauleSkinner said:
You could, but you’d be wrong. The forecast isn’t calling for ceilings below 4500 feet until after 1800.

As @dmspilot said, this isn’t really about needing an alternate, it’s about reading and understanding TAFs.
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In either case, he would NOT need an alternate.
 
Oh, I thought you said "alternator required". I was going to say, "me, too!"
 
buzzard86 said:
I'm well into my instrument training and was working with a different instructor today on some knowledge prep. I know the 1-2-3 rule for requiring an alternate, but got tripped up on a question today that has me re-thinking my interpretation of how the rule is applied.

The scenario presented was something like this:

ETA: 1500Z

TAFs:
FM111400 20009KT P6SM BKN045
FM111800 27012KT P6SM OCV015

My interpretation was that I did not need an alternate because the wx 1 hour before (1400Z) and after (1600Z) my ETA was greater than 2000'/3SM (ie, it was going to be BKN045 until 1800Z). However, he said that I did need an alternate because the later TAF was below 2-3 and there was no way to know when conditions would fall below 2000 leading up to that OVC015 @ 1800Z.

I understand the logic and don't want to overthink this, but I'm sure that this will come up in my oral and I want to make sure that I can answer it correctly and confidently. Technically what's the correct answer here?
Click to expand...
I think you were right under US rules. If/when you decide to fly to Canada after getting your rating (and I hope you do some day), remember a couple of differences here:

1. If you file IFR, you always have to file an alternate, even if it's CAVU.
2. To file IFR, you have to be both instrument-rated and current, even if it's CAVU.

There are a few other differences (e.g. MSA is operational rather than advisory here here--when you're cleared for an approach, you're automatically cleared to descend to MSA unless ATC says otherwise), but they won't come up much in your normal flying. In the meantime, good luck with your training!

D
 
David Megginson said:
I think you were right under US rules. If/when you decide to fly to Canada after getting your rating (and I hope you do some day), remember a couple of differences here:

1. If you file IFR, you always have to file an alternate, even if it's CAVU.
2. To file IFR, you have to be both instrument-rated and current, even if it's CAVU.

There are a few other differences (e.g. MSA is operational rather than advisory here here--when you're cleared for an approach, you're automatically cleared to descend to MSA unless ATC says otherwise), but they won't come up much in your normal flying. In the meantime, good luck with your training!

D
Click to expand...
Technically, #2 is true in the U.S. as well.
 
MauleSkinner said:
True...but I’d rather not need an alternate because I understand the TAF than not need one because I don’t understand the TAF.
Click to expand...

Agree that the TAF is the "official" source, but he didn't have a TAF for 1 hr after his arrival. I was just indicating that the student could have (in theory) counter argued with the statement that, while it's impossible to predict how fast the ceiling would actually drop, given the TAF data, while I would assume conditions to be worse than the first TAF, I would not assume them to be <2000 at 1 hour after the ETA based on the data.

Interestingly, the AWC does interpolate ceiling/visibility data for stations that don't have METARS reporting capability. While the AWS indicates us regular folk should avoid interpolating data, they do indicated one can make some assumptions....

https://www.weather.gov/media/psr/L...Application of Aviation Weather Forecasts.pdf

Graphical products display a "snapshot" of expected conditions at a specific valid time. Avoid interpolating between periods. Operationally, should lower conditions exist at the previous valid time, consider those conditions to exist through the next time period. Should lower conditions prevail at the subsequent valid time, apply those conditions during the intermediate interval. Users should assume lower conditions exist between "snapshot" valid times.
 
Yes, you need an alternate instructor.
 
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