How to memorize cloud clearances and equipment requirements.

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ayryq@reddit

For cloud clearances, I find it easier to think of it in terms of "standard" and "exceptions." There's only a few exceptions to the 3/152 rule. Class B 3/CoC, Class G day 1/CoC, and Class E over 10,000 5/111. That's it unless you fly in Alaska or that one spot in Texas.

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belugey@reddit

Knowing the reason for the exceptions helps me too. 3/152 is based on giving you enough time to see an avoid a jet that pops out of a cloud pointed at you at 250kts.

Class B 3/CoC - ATC separates all aircraft (this is why you need a clearance to enter the bravo). Because there's no possibility of a jet being near you, you can get right up next to the clouds safely.

Class G day 1/CoC - Uncontrolled airspace so no IFR jets in the clouds.

Class E over 10,000 - Above 10k the speed limit goes away so you need more time to see and avoid a jet coming out of a cloud at you.

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dylanm312@reddit

Agreed with all except the class G reasoning. Is there a reason an IFR aircraft can’t land at an untowered class G airport?

Or do they always set up the class E “shelves” (magenta vignette and dashed magenta line) at untowered fields in order to contain all approaches down to the lowest minimums? Genuine question, I’m not sure.

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belugey@reddit

Yeah it's true which is why those shelves exist. You could be at 699' AGL and right up next to clouds with a jet coming at you on an approach. I would hope that scenario is pretty rare given that patterns should typically be flown at 1,000' AGL.

And technically planes can be flying through clouds in G not on an instrument flight plan though I would hope that happens so rarely that it could be considered an impossibility (at least in the US).

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randombrain@reddit

In the general case it is legal to fly IFR/IMC without a flight plan in Class G airspace. The problem is that the 91.177 minimum altitudes are going to be lower than the controlled-airspace floor basically everywhere in the country, aside from those vanishingly rare areas that still have Class G up to 14.5. So in reality it can't be done, at least not anymore.

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randombrain@reddit

Well the lowest minimums are going to be 200' on an ILS/LPV, and the Class E floor (if there isn't a surface area) is 700'. So you're correct, there very well could be an IFR aircraft operating in Class G airspace near a non-towered airport.

Anyone who's IFR should have a radio and therefore should be making calls on CTAF, so you would listen to the CTAF and not hang out on the final when they're inbound. And it probably isn't a great idea to be operating when the WX is bad anyway, even if it is legal.

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dylanm312@reddit

Oh for sure, the odds of encountering this issue in real life are slim to none. Just doing a thought experiment about what’s technically possible.

Let’s say John Doe wants to take his piper cub up for some patterns at a class G airport with the standard 1200’ AGL floor. Ceilings are 1100 AGL. Since the plane has no electrical system, he has no radios (forgot the handheld at home). But because radios are not required for untowered fields, he concludes this isn’t a problem. Because he plans to fly in the pattern at 1000 AGL, which is 1sm/CoC, he decides it’s safe to blast off and start doing some touch n gos.

Meanwhile, EJA123 is a C25C on the RNAV Z (LPV minimums) approaching the gate for this same airport. They get switched to CTAF and ATC protects the airspace around the airport from other IFR departures and arrivals. But they cannot see the cub since he has no transponder, let alone ADSB, and anyway they have no authority or responsibility to separate aircraft in class G. EJA123 is making traffic calls, but John can’t hear them.

John is at 700 AGL on a left base, doing about 55 KIAS, about to turn final, when the CRJ pops out of the clouds at 1100 AGL doing 120 KIAS. With no time to react, the CRJ runs him over.

Questions: - Is this scenario possible? - Is the airport required by TERPS to have class E airspace down to/below the lowest minimums (so down to the surface in this case)? - Does traffic volume (IFR vs VFR, itinerant vs local) factor in to deciding where the class E shelves should be placed?

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randombrain@reddit

Everything about your scenario is very possible. Unlikely, but possible.

There's no requirement for an instrument approach to exist only in controlled airspace, and Class E surface areas aren't designated based on traffic levels. In order for a surface area to exist, there must be both 1) on-airport WX reporting and 2) on-the-ground radio comms capability with ATC. (Everyone has cell phones now, but they didn't used to, and the rules still require it in a roundabout way: the Class E paragraph points to the Class D paragraph that points to the WX and comms requirements.)

The one thing about your scenario is that (with perhaps one or two exceptions proving the rule) at all airports having IAPs, even if there isn't a Class E surface area there will still be a Class E transition area down to 700' AGL. Not 1200'. But John Cub could still be operating 1SM/CoC below that.

Unless you know of a regulation that requires pattern work to always be conducted at the published pattern altitude.

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Thomas-Ligotti97@reddit

Screenshotting this to explain to my students

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diamonddealer@reddit

That one spot in Texas?

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ayryq@reddit

One of the rules you are supposed to learn is 1SM/152 in class G above 1200 AGL. Where I live in NY, there's literally no class G above 1200 AGL. But there's a bit of it in Alaska, and a smaller bit in the American southwest. Look around 93TE for an example.

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Goop290@reddit

Check off the coast the zipper line usually has G up to 5500 atleast on the west coast

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ayryq@reddit

Good point, we have those on the east coast too. Most are in Warning areas, but still...

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Flyinghud@reddit

In southwest Texas right on the US-Mexico border, theres a spot where class G goes up to 14,500

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Daa_pilot_diver@reddit

I believe they are referencing the class G airspace over by Big Bend that is G up to 14,500. Interestingly enough, the cloud clearances are the same above 10,000 for G and E.

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Virtrudian@reddit

This is my new favorite comment

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spacecadet2399@reddit

There's a triangle out there on the internet that helped me a lot...

If you're a visual learner, anyway. Just do a Google image search, it'll come up.

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Mega-Eclipse@reddit

Just Plane Silly's method. The guy makes silly videos, but this is one of his serious ones. And it legit helped memorize the requirements in about 5-10 minutes.

After drawing his picture 4-5 times, you can start to visual it in your head and can answer VFR mins in like 3-4 seconds.

Seriously, this is the one!!!

This one

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San_Cannabis@reddit

MOOFACTAR

Manifold pressure gauge Oil temp Oil pressure Fuel gauge Airspeed Indicator Compass Tachometer Altimeter Radios

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StrangeCow6712@reddit

Nice, a pile of parts

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DigitalNomadicYogi@reddit

Check out RocketShipGame.net

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swaggler@reddit

Spaced repetition.

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cazzipropri@reddit

Rod Machado's airspace pyramid. Find the youtube video, practice 20 times and you are done.

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gruesome_hary@reddit

Cessna 152 - 3sm, 1,000ft above, 500ft below, 2sm horizontally

F-111 5 miles, 1,000 above, below and 1sm horizontally

The f-111 flew high, so it’s above 10,000ft

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Franks2000inchTV@reddit

The best way is to come up with your own mnemonic, and create sensory images to help you remember.

I still remember the order of taxonomy by a dumb thing I came up with in grade 9: Silly George Found Other Cokey Pokey Kids.

Species Genus Family Order Class Phylum Kingdom.

The sense memory was easy because AI had a huge crush on my lab partner. 😂

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ExpensiveCategory854@reddit

I'm a visual learner and seemed to really like the Rod Machado airspace triangle: https://www.youtube.com/watch?v=3f0pUpBo8gg He also does a good job with a memory aid you can use for CDI deflection on VORs for the written. When I did mine, I wrote them down immediately on a piece of scrap paper when I was at my test station just in case. Ultimately I didn't need them but gave me peace of mind.

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keenly_disinterested@reddit

I like Rod Machado, but I think his triangle is a bit difficult to comprehend. I prefer this one:

https://youtu.be/uwyh2F81-GM?si=URU3XURx19txd-Uf

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Living_Guess_2845@reddit

I kept the On Centerline podcast on repeat everywhere I drove. I also put a copy of the acronyms in my knee board just in case I needed to reference.

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SquareGrade448@reddit

I tried to learn the VFR cloud clearances over and over again for months. The triangle thing was useless for me, as was the way the FAAsafety.gov resource lays it out.

Caliber Aviation's pdf finally unlocked it for me. Studying this just a few minutes made it finally stick -- I highly recommend trying it.

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ryancrazy1@reddit

Repetition helped me. In the weeks leading up to my IFR Checkride, every time I thought about it, i looked it up and read them out loud.

2 hours later and I think of it again, I recite outloud, after I say it, I double check I was correct.
I feel like it’s very helpful to verbalize when learning.

Eventually, you’ll have gone over it enough that you are just familiar with it.

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imfenbored@reddit

Rod Machado's triangle. Draw it over and over again until you can do it from memory. Then just picture it in your head when you need to remember. Eventually you'll just know them.

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YountainOfFouth@reddit

This is much easier and simpler

https://youtu.be/B_4Z8XBtMkE?si=lYTDPacvK-dQFcYi

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YountainOfFouth@reddit

As a visual learner this video really helped me learn the airspace requirements.

Avoid Robs triangle and simplify your life with this.

https://youtu.be/B_4Z8XBtMkE?si=lYTDPacvK-dQFcYi

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poser765@reddit

Just fucking brute force rote memorization. Make flash cards or whatever. Know it for the checkride then brain dump it. Reference as needed for real flying.

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ShelbyDriver@reddit

Eh, don't brain dump so fast. You need it for instruments.

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poser765@reddit

Yeah definitely… poor wording in my choice. When I said check ride I meant out of training and no longer facing ANY checkride.

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AtomicShadow117@reddit

What I did was I looked at all of cloud clearances and equipment requirements really hard

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Prof_Slappopotamus@reddit

This cracks me up, because I'm picturing your profile guy just staring super hard at a desk with the AIM open.

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Akepur@reddit

In lieu of memorizing the equipment. I always just said the regs in all my checkrides Inop equipment flow.

MEL? Yes. Follow the MEL. MEL? No. 91.205, KOEL, TCDS, ADs, not required? Follow 91.213.

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redditburner_5000@reddit

Memorize visibilities as a phone number and then attach justification to the cloud requirements. It's so much easier than just trying to memorize a bunch of numbers.

Basic rules:

3sm is almost always +1000, -500, «2000», except class B

5sm is always +/-1000, «1mi»

There are only two 1mi vis, and they are G daytime. Above 1200, you'll have to have some buffer but below you just have to stay out of clouds.

The phone number: 333-535-1313

Start at A and work down to G

A - IFR only, irrelevant to VFR

B - 3sm and clear of clouds since they can't have you going 2,000 out of your way in their airspace and it's heavily monitored. There won't be anyone popping out of clouds willy nilly in B. You just need to stay out of clouds.

C - 3sm and +1000, -500, «2000» (the "standard")

D - 3sm and +1000, -500, «2000»

E (above 10k) - 5sm and +/-1000, «1mi» because nobody is really watching and you'll have faster planes above 10,000 so you need more room to see and avoid, hence the larger vis and cloud reqs.

E (below 10k) - 3sm and +1000, -500, «2000»

G has five variants, but they make sense.

G (above 10k) - 5sm and +/-1000, «1mi» because nobody is watching and you'll have faster planes above 10,000 so you need more room to see and avoid, hence the larger vis and cloud reqs.

G (above 1200agl day) - 1sm and +1000, -500, «2000» because you're in basic GA territory and they're slow, but faster than a trike. The idea is that you're not doing 200kts down low, so you don't need the larger buffers of E and G above 10k.

G (above 1200agl night) - 3sm and +1000, -500, «2000»

G (below 1200agl day) - 1sm and clear of clouds because nobody really GAF and we're down in ultralight territory here. Really low bar. Just be able to see a little and don't actually go into a cloud.

G (below 1200agl night) - 3sm and +1000, -500, «2000»

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fromtheleftseat@reddit

A good start is memorizing in which airspace the requirements are the same. I found it helpful to reframe it such as 3-152 is good in C,D and E below 10, and most G (except for below 1200AGL and above 10K).

Also learning why it changes outside of those parameters helps. If you know, the “why” the “what”sticks better.

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Different-Wish-843@reddit (OP)

just did this and it helped

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Sad-Umpire6000@reddit

Start by knowing why there are different requirements. In Class G, you are generally below the flow of IFR traffic, and fairly close to the ground. No fast movers. Class E, D and C have IFR traffic, and once you get above 10,000 feet, there are planes that are hauling butt. Keeping farther from clouds gives more reaction time. Class B can have lower visibility and you can be closer to clouds, because everyone is being separate by ATC.

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jcurve347@reddit

There's a just plane silly youtube video from a few years back where he describes the 3-1-3 method for remembering how/when things change for Class G and Class E airspaces and how those link in with B, C, and D cloud clearance requirements as well.

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KehreAzerith@reddit

All I did was read it over and try to write it down over and over until you memorize it. There is a triangle method too if you need organization

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scottyh214@reddit

The standard is 3 miles, thousand above, five hundred below and two thousand horizontal from clouds. Know that by heart. From there, form an understanding of WHY things change in various airspace’s then you’ll know what they are.

It changes above 10,000 feet. WHY? I’ll tell you exactly why. When I fly the Citation X, I’m limited to 250 knots below 10. The moment I hit 10,000, I lay the airplane down and accelerate. If I pop out of a cloud doing 300+ knots, I need that mile to avoid you. I also generally descend faster up high, sometimes 2500-3000 FPM or more, so we need more space below the cloud too. Hence, your cloud clearances and visibility requirements increase. 5 miles of visibility a mile lateral and a thousand above and below sounds reasonable.

Class B is different. Why? Because you need a specific clearance to be in that airspace and you are bound to comply with ATC instructions (yes you can - and must - tell them you need to deviate from clouds) so they know exactly where you are, exactly what you’re doing and they can separate IFR traffic from you or you from them. The 3 miles of visibility is still good but now, as long as you’re not IN the cloud, you don’t need to be able to be seen and avoided by that IFR jet. Just stay clear of clouds.

This works across the board with everything, not just VFR mins. Don’t try to memorize things. Rote memorization really doesn’t help anything. If you understand WHY something is, you’ll intuitively know the what.

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