What's "actual"?

Palmpilot said:
The FAR and P/CG definitions for IMC are quoted above and earlier in the thread. The one for VMC is in the P/CG, but not in the FARs that I can find.

"VISUAL METEOROLOGICAL CONDITIONS−
Meteorological conditions expressed in terms of
visibility, distance from cloud, and ceiling equal to or
better than specified minima.
(See INSTRUMENT FLIGHT RULES.)
(See INSTRUMENT METEOROLOGICAL
CONDITIONS.)
(See VISUAL FLIGHT RULES.)"
​
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Just helping with the search here, no other comment...

The words “Visual meteorological conditions” exists in:

The definition of Special VFR in FAR 1.1
In the Mitsubishi MU-2 special FAR 91.1717 <- Interesting
FAR 135.293 <- Helicopter specific
FAR 170.3 <- That one is a semi-definition for only that sub-part
AIM 1-1-7, 5-2-8, 5-4-23, 5-4-27, and 10-2-2.

And your PCG reference that appears to be the only actual definition of the term, of course.

AIM 4-5-6, 5-3-4, and the definition of “Special VFR Flight [ICAO]”, all rather sloppily refer to it only as “VMC”.

——

“Instrument Meteorological Conditions” is mentioned all over the place, comparatively with the caveat that intentional or not, whoever wrote most of Part 121 reverted to saying only “Instrument Conditions” nearly everywhere in that Part. Whereas it’s the full phrase in everything else, including 135, 141, 170.3, etc.

And again like “VMC”, “IMC” is sloppily used throughout the AIM.

Just playing with my search thingy here for fun.
 
By the way, the tortured words used in definition for “IFR Conditions” was probably put in there when “Special VFR” was added... think about it... there’s two types of “VFR”... so some poor soul just changed it to avoid linguistically infringing on either type.

Anybody have a FAR/AIM around from before SVFR existed? I bet the “IFR Conditions” definition changed... or didn’t exist... I bet someone twisted their panties around the flagpole trying to get those definitions not to step on each other and it’s never been rewritten clearly.
 
dmspilot said:
No, that is not what I postulate.

IFR conditions is a term defined by FAR 1.1 and it does not mean "IFR + Conditions".

---

What I postulate is that

"weather conditions below the minimum for flight under visual flight rules"

equals

"meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling less than the minima specified for visual meteorological conditions".
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I should have used a smiley, you didn't get my sense of humor. No worries. Here's my real answer:

This is really a matter of semantics, and a failure to invent a term describing conditions which do not meet the weather criteria for either IFR conditions or your definition of IMC yet require you to stay on instruments to keep the dirty side down. I am of course talking about the JFK Jr over water scenario, or say you're in Alaska with a ceiling above, treeless snow covered landscape below, wiping out your orientation wrt the horizon. These are not technically IMC as defined, and definitely not "IFR conditions" because you may conduct the entire flight perfectly legally under VFR.

In such cases the VMC is technical; you are really in conditions requiring instruments, but if we can't call it IMC due to the visibility/cloud clearance definition, and we can't call it IFR conditions because of the same reason, we are in need of another term.

The reason we need another term is that we are talking about two completely different problems: Traffic separation, and keeping the airplane right side up. Under the conditions I describe, you can still see traffic from miles away, it's legal VFR and it's VMC. But you cannot conduct the flight by visually relying on a horizon, so you must be on instruments (either your eyes or autopilot) so it's actually IMC for problem number 2. It may also be IFR conditions if you do not have a safety pilot to watch for traffic or don't have autopilot. But it might not be if you do.

I have always practiced parsing them depending on what I'm really talking about. If I use "IFR conditions" in a statement I'm implying what set of rules you are (or not) flying under and I have the idea of traffic separation in mind. If I use "IMC" in a statement I am only talking about the weather and I'm usually thinking more about keeping the dirty side down. But that's just me.
 
Rushie said:
The reason we need another term is that we are talking about two completely different problems: Traffic separation, and keeping the airplane right side up. Under the conditions I describe, you can still see traffic from miles away, it's legal VFR and it's VMC. But you cannot conduct the flight by visually relying on a horizon, so you must be on instruments (either your eyes or autopilot) so it's actually IMC for problem number 2. It may also be IFR conditions if you do not have a safety pilot to watch for traffic or don't have autopilot. But it might not be if you do.
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Excellent post. Just one small nit, concerning the part I bolded: I don't think "IFR conditions" is a good description of this scenario whether you have a safety pilot or autopilot, or not. First, because it is still legal to be VFR in these conditions, while the term "IFR conditions" usually implies that you have to be IFR to be legal; and second, because even if you are IFR, you are not relieved of see and avoid responsibility because ATC is not (assuming this is in Class E airspace, maybe it isn't if you're in Alaska) responsible to separate IFR traffic from VFR traffic, and there still might be other traffic out there that is legally VFR. In other words, being IFR won't help you if you don't have some way to look out for other traffic.
 
EdFred said:
And in all of your yammering, I see you never once addressed IMC - which is not exactly the same as IFR conditions.
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One must follow a train of thought one step at a time and not skip directly to the destination.

First we must establish the definition of "IFR conditions". If you cannot accept the FAA definition without adding your own spin to it then there is no point in continuing this discussion.
 
azure said:
Excellent post. Just one small nit, concerning the part I bolded: I don't think "IFR conditions" is a good description of this scenario whether you have a safety pilot or autopilot, or not. First, because it is still legal to be VFR in these conditions, while the term "IFR conditions" usually implies that you have to be IFR to be legal; and second, because even if you are IFR, you are not relieved of see and avoid responsibility because ATC is not (assuming this is in Class E airspace, maybe it isn't if you're in Alaska) responsible to separate IFR traffic from VFR traffic, and there still might be other traffic out there that is legally VFR. In other words, being IFR won't help you if you don't have some way to look out for other traffic.
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Also excellent points; I concede your nit.
 
dmspilot said:
One must follow a train of thought one step at a time and not skip directly to the destination.

First we must establish the definition of "IFR conditions". If you cannot accept the FAA definition without adding your own spin to it then there is no point in continuing this discussion.
Click to expand...

14CFR1.1
IFR conditions means weather conditions below the minimum for flight under visual flight rules.

Which is IFR conditions?
1/2SM and OVC005
or
P6SM and SCT050?

The first one right, since that's below minimums and the second one is above minimums? Weather charts also display IFR Conditions as <3/<1000. They never display IFR Conditions where the vis and cloud bases are above that.

Good, we've established IFR Conditions.

I can't find IMC or Instrument Meteorological Conditions in 14CFR1.1 so we will go to the PCG

INSTRUMENT METEOROLOGICAL CONDITIONS
Meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling less than the minima specified for visual meteorological conditions.

This is not the same definition as IFR Conditions. IFR C doesn't say anything about distance from clouds. IMC does.

We can agree that the 1/2SM and OVC005 is also IMC because of visibility/cloud clearance.

However, if I decide to fly at 4900AGL, in the P6SM SCT050 scenario, guess what, distance from clouds makes me IMC. It's still not IFR conditions, because P6SM and SCT050 is not IFR Conditions, but depending where I fly I can be in IMC.

Example: I was flying through a Charlie and it was SCT025. (3300MSL round here) I wanted to fly at 3000MSL and requested SVFR. Approach said no can do, it's not IFR Conditions. But had I ventured too close, or been in the clouds, I would have been IMC even though the conditions were above minimums.

So like I said from the get go IMC != IFR Conditions. If they were exactly the same, they would be defined exactly the same.

You are now free to yammer.
 
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EdFred said:
14CFR1.1
IFR conditions means weather conditions below the minimum for flight under visual flight rules.

Which is IFR conditions?
1/2SM and OVC005
or
P6SM and SCT050?
Click to expand...

Minimum weather conditions for VFR flight are spelled out in 14 CFR 91.155, and in subparagraph (a), specify flight visibility and distance from clouds. Just because 91.155(c) and (d) prohibit VFR flight in a controlled airspace surface under a 1,000' ceiling or with ground visibility of less than 3sm, this does not eclipse the basic minimums required for VFR flight in 91.155(a).

The title of 14 CFR 91.155 is "Basic VFR weather minimums" -- so the minimum weather conditions for flight under VFR includes ALL of the weather minimums in 91.155, including distances from clouds and flight visibilities, NOT merely ONLY reported ceiling and ground visibility required by subparagraphs (c) and (d) as your assert.

EdFred said:
The first one right, since that's below minimums and the second one is above minimums?
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You are trying to assert that IFR conditions can only occur on the surface, when the definition is that IFR conditions exist whenever weather is less than the minimum for flight under VFR. Minimum weather for VFR is described in 14 CFR 91.155, "Basic VFR weather minimums," and most certainly includes distances from clouds and flight visibility which apply to every point in the atmosphere, not just on the ground.

EdFred said:
Weather charts also display IFR Conditions as <3/<1000.
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This is a convention and weather charts depict conditions only at the surface. Weather charts also depict "LIFR" and "MVFR" which are not legal terms.

EdFred said:
However, if I decide to fly at 4900AGL, in the P6SM SCT050 scenario, guess what, distance from clouds makes me IMC. It's still not IFR conditions, because P6SM and SCT050 is not IFR Conditions, but depending where I fly I can be in IMC.
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91.155(a) requires weather minimums for VFR to include being at least 500 feet below a cloud in Class E airspace. If you are only 100 feet under a cloud, you are in a place where the weather is below VFR minimums. What is it called in a place where weather is below VFR minimums? IFR conditions.

 
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I guess that's why they issue airmets for IFR conditions when it's scattered 5000. Oh wait they don't. Because they are not IFR conditions. VFR and IFR are rules by which we fly. Intentionally flying near something does not change the weather conditions and that is the problem you are having trouble understanding. A 5000 foot scattered layer will never ever ever be IFR conditions. You have to follow certain rules but that does not change the weather conditions.

I see you conveniently ignore the example I provided where the FAA themselves said it is not IFR conditions. Of course I see why because it totally destroys your argument. And don't bother responding because I'm done with this thread.
 
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EdFred said:
I guess that's why they issue airmets for IFR conditions when it's scattered 5000. Oh wait they don't. Because they are not IFR conditions. VFR and IFR are rules by which we fly. Intentionally flying near something does not change the weather conditions and that is the problem you are having trouble understanding. A 5000 foot scattered layer will never ever ever be IFR conditions. You have to follow certain rules but that does not change the weather conditions.
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If you fly VFR at 4,900 with a cloud layer at 5,000, you have violated 91.155, "Basic VFR weather minimums." In other words, you have flown in weather conditions below the minimum required for flight under visual flight rules. You are, by definition, operating in IFR conditions.
 
dmspilot said:
If you fly VFR at 4,900 with a cloud layer at 5,000, you have violated 91.155, "Basic VFR weather minimums." In other words, you have flown in weather conditions below the minimum required for flight under visual flight rules. You are, by definition, operating in IFR conditions.
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There are Part 135 certificate operators who have authorizations to fly in MUCH lower conditions and cloud clearance requirements than Part 91’s and other definitions of VFR, who are specifically told they are NOT operating IFR.

You also ignored Special VFR which I mentioned earlier as a more accessible example, since most of us here don’t have access to certain company’s operational documents showing their lower VFR limits.
 
^^^ in other words, FAA can change the meaning of the term VFR any time the feel like it. Your “VFR conditions” may not be someone else’s “VFR conditions”.
 
denverpilot said:
There are Part 135 certificate operators who have authorizations to fly in MUCH lower conditions and cloud clearance requirements than Part 91’s and other definitions of VFR, who are specifically told they are NOT operating IFR.

You also ignored Special VFR which I mentioned earlier as a more accessible example, since most of us here don’t have access to certain company’s operational documents showing their lower VFR limits.
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Exceptions to the rule don't refute the rule's existence. I left out Special VFR for the sake of simplicity, it doesn't contradict the point.
 
dmspilot said:
Exceptions to the rule don't refute the rule's existence. I left out Special VFR for the sake of simplicity, it doesn't contradict the point.
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It does once you realize VFR truly is undefined by itself and only defined by the operating limitations of a particular set of rules the pilot is flying under, and those rules can be overridden for any particular pilot with nothing more than an approval letter from the Administrator.

It has no definition. It’s a clump if words that refers to a specific set of limits. We teach newbie pilots it means what Part 91 says, but that’s just because they’ll be flying under Part 91.

We find out later that there’s all sorts of limitations in Part 91 that aren’t definitions like we thought they were, when we were taught that accidentally.

The definition is the one already quoted... which is purposefully vague enough it means whatever FAA wants it to mean, and can even change it for individual operations at the pleasure of the Administrator.

And has. Some operators have limits of 300 below and 2 miles and have been specifically told they’re not IFR operators, nor allowed to be.
 
We live in an imperfect world!
 
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