All About Airspace – Flight Lesson 16

Flight Lesson #16 – Flying in Class B airspace
Flight hours: 0.9
Hours to date: 19.6
December 27, 2011

No two classes are the same.  That’s the basic lesson I needed to keep in mind as I set out for a quick flight through some Class B airspace.  The plan?  Stay calm and keep focused as I navigate my way to the airport, communicate with air traffic controllers en route, and ultimately compete with a gaggle of 737s and A320s for landing space at the Kansas City International airport (KMCI).

A great evening for a flight

Before heading out for my flight on what was shaping up to be an awesome winter evening, I needed to figure out the difference between Class A, B, C, D, E, and G airspace.  Each airspace class has a different set of requirements and I know that if I want to get my license, I’ll need to know those requirements like the back of my hand.  In case you were wondering, here are those requirements.  Buuuuut, before that I’ll just say that I had a great time on this flight.  The winds were calm, the air was smooth, and the skies were beautiful.  I felt pretty comfortable on the radio with ATC, mainly because it was a relatively slow evening at KMCI so they were a bit more patient with me when I called in.  The landings felt pretty nice, although I’d like to walk back the landing at KMCI again.  Not that it was bad per se, but I was looking for a little more of a “greaser” landing on that one, especially since I know everyone inside the terminal was plastered to the windows to check out the kick-butt Cessna 172 coming in to land at the International Airport.  “Hey Bob, forget about that Airbus A380 on the ramp, we’ve got a Cessna on short final!”

If you like, you can follow the link to watch a video of the flight.  I apologize in advance, I’m not a videographer or a soundtrackographer (if that word didn’t exist before, it does nowJ ).  I added some music to the video since all of the communication w/ Austin and ATC were obscured by the sound of the engine, and 6-minutes of a Lycoming engine at 2,200 RPM can get old a little quickly.

OK, here’s the quick pseudo-tutorial on airspace, at least this is how I rationalize airspace when I’m chugging along on a flight.

Class A airspace– The “A” stands for “altitude” and I won’t have to worry about this one…yet.  I guess the “A” could also stand for “absent” since Class A airspace isn’t marked on sectional charts. Basically, everything between 18,000 feet and 60,000 feet MSL (above sea level, this distinction is important) is considered Class A airspace and I’m pretty sure I’d end up with a good bit of hypoxia if I tried to climb the unpressurized Cessna 172 up to 18,000 feet.  Even if I felt like getting a little hypoxic, I’d have to do it in another plane as the -172 has an effective service ceiling of roughly 14,000 feet.  Let’s say, however, that you’re Mark Zuckerberg-day 1-of-the-IPO-rich  and you’ve somehow picked up a demilitarized B2 bomber (yes, this is fantasy land) and you’re itching to go for a nice stealthy flight at 45,000 feet.  What would the requirements be to get up there?  The only thing you really need (other than an airplane that will climb above 18,000 feet) is an instrument rating because VFR flight is prohibited in Class A airspace.  If you’re all set with your instrument rating and you’re ready to fly IFR, then you’ll need to contact ATC in order to get clearance to enter Class A.  Since flight in this type of airspace will be instrument based, there are no restrictions in regards to visibility or clearance from clouds.  Other types of airspace permit VFR flight and will note required minimum visibilities since the last thing you’d want is to be in the midst of a nice and leisurely VFR flight near some huge cumulonimbus clouds only to have a 747 come barreling out, straight into your shiny new airplane.  I have a feeling I know which plane would win that battle.  To sum up Class A, it’s the airspace between 18,000 and 60,000 feet.  You need an instrument rating (no VFR flight allowed), and you need to contact ATC prior to entering the airspace.  B2 Spirit bomber not necessary to enter.

Off we go into the wild blue Class A airspace

Class B airspace – The “B” stands for “big” and “busy”.  Sectional charts show this airspace as concentric blue circles surrounding the nation’s busiest airports, meaning the skies of Class B are typically filled with large commercial airliners. (Here’s a list of all Class B airports in the US, I guess the link says it all:  In order to keep the millions of flying passengers safe, Class B airspace is tightly controlled and there are certain requirements that must be met by the pilots and airplanes that traverse it.  Before I get to the restrictions, I should probably start by describing what this airspace looks like on your charts.  Picture a nice, big, blue wedding cake that’s at least 3 layers tall.  Now take that cake and turn it upside down and you’ll have Class B airspace.  The smallest layer (what would have been the top layer of the cake before you flipped it upside down) surrounds the airport and extends from the surface to an altitude of up to 10,000 feet (generally).  The next layer extends beyond the smallest layer, but it extends from the general altitude of 10,000 feet down to a pre-specified altitude above ground level.  Looking at a sectional map, to the side of one of the blue rings you’d see something like 70/40 for example, which means the Class B airspace extends from 4,000-feet to 7,000-feet MSL.  If it said 70/sfc it would mean the Class B airspace extends from the surface to 7,000-feet MSL.

So now that you know what Class B airspace would look like on a map, what do you need to know before you blast through the outer ring?

First, the weather.  You need to make sure that you are:

-Clear of clouds

-Able to see at least 3 statute miles in each direction

You also have to have the following equipment installed on your airplane:

-A two-way radio that actually works so you can talk to ATC

-An operating transponder that is equipped with automatic altitude reporting (Mode C) so that ATC can not only see where you are, but also how high you’re flying

Finally, your personal requirements as a pilot are that you either:

-Hold at least a private pilot certificate; or

-Are a student pilot or recreational pilot in the midst of working on a private pilot certification and who meets all of the FAA requirements, specifically those found in CFR Section 61.95.

Probably the most important thing to keep in mind when getting ready to move into Class B airspace is that you have to get permission from ATC before you do.  In this case, “permission” doesn’t mean telling the controller, “Hey! I’m going to fly over your way now, okay thanks bye.”  It means that you have to call the controller, state your request, and then wait on them to say, “cleared to enter Class Bravo airspace”.  The situation may present itself where you call ATC with the request and they’re not able to get back with you right away due to a heavy workload, but you’re literally at the threshold of Class B.  If that’s the case, you have to alter your flight path to avoid entering the airspace until you hear those magic words, “cleared to enter…”  Just remember “ABC” – Always Be Cleared.

Class C airspace – Class C airspace surrounds airports that are busy, but not as busy as those in Class B airspace.  These airports have an operational control tower, they will have radar approach control services, and will see a fair number of IFR and commercial flights. This airspace is marked with sharp-bordered magenta circles (not fuzzy lines [see Class E]) and it generally extends from the surface to 4,000 feet above the airport. There are typically 2 rings with the first layer (the small layer of the wedding cake) extending 5 nautical miles from the airport laterally, and from the surface to 4,000 feet AGL.  The second ring typically extends 10 NM from the airport and then from 1,200 to 4,000 feet AGL.  To enter the airspace, you need to establish two-way communication with ATC although you don’t need to hear the explicit “cleared to enter” acknowledgement that you do with Class B.  You also need to have a working Mode C transponder installed so ATC can see what altitude you’re flying at.  As far as weather, here’s what you need to know if you’re flying VFR:

Visibility – You should have at least 3 SM of visibility in all directions

Clouds – You need to stay at least 1,000 feet above the clouds, 500 feet below the clouds, and at least 2,000 feet away horizontally.  The easy way to remember this is to think of a Cessna 152 where the “152” represents your distance above, below, and away from clouds, respectively.


Class D airspace– This is what I’m most accustomed to flying in since KOJC is located within Class D airspace.  In the spirit of using mnemonics to help remember these airspace classifications, the “D” could stand for “Dime-sized” since Class D airspace is usually the airspace of choice for small “dime-sized” city airports that have an operational control tower.  On your sectional chart, it’ll be marked as a blue-dashed circle and the airspace typically extends from the surface to an altitude of 2,500 feet above the airport.  You do have to make contact with the tower in Class D, but you don’t have to receive explicit clearance into the airspace and you don’t have to carry a Mode C transponder.  Your visibility and weather minimums will be the same as for Class C, so don’t forget your Cessna 152 (1,000 feet above clouds, 500 feet below, 2,000 feet horizontally, and 3 SM visibility).

Raptor launching from Rosecrans Memorial (KSTJ) – An airport in Class D airspace

Class E airspace – For some reason, this airspace classification always confused me a bit, until, that is I figured out how to think about it a little more rationally.  To do that, I’m going to skip to Class G airspace and then come back to Class E.

Class G airspace – This is the only type of uncontrolled airspace we have in the US. Think of “G” as “ground”.  Class G airspace typically covers everything from the surface to 700 feet AGL or 1,200 feet AGL in all areas not occupied by Class B, C, D, or E airspace (I didn’t mention Class A because that doesn’t start until you hit 18,000 feet above sea level).  I think the first thing I should explain here is controlled vs. uncontrolled airspace since that’s the biggest distinction here.  Controlled airspace simply means that ATC has jurisdiction over these chunks of air and they are there to provide separation services to airplanes flying IFR.  They are also there to provide flight following for aircraft flying VFR, although this is on a time permitted basis since their real priority is keeping those pilots flying on instruments clear of other traffic.  (Flight following is basically a service in which ATC will alert you if there is traffic in your vicinity, although it’s still your job as pilot-in-charge to keep an eye out for traffic).  Uncontrolled airspace, therefore, is that airspace where ATC doesn’t have jurisdiction and they aren’t able to provide separation services for aircraft flying IFR.

Okay, so back to class G so I can try to muddle my way through explaining where it exists, although if you keep in mind that Class G likes to hug the ground, it’s a lot easier to remember.

Let’s say that you’re flying across a nice flat expanse of ground and there are no airports in sight (and of course no restricted areas, obstructions, or anything else of that nature).  In this area, Class G (uncontrolled) airspace is going to run from the surface up to 1,200 feet above the ground.   As you’re flying, you look at your sectional chart and realize that you’re about to cross over one of those fuzzy magenta circles.  As soon as you cross the theoretical fuzzy magenta boundary, your Class G airspace drops from 1,200 feet to 700 feet above the ground.  As you fly a bit further, you may cross over a dotted magenta circle, which means that Class G officially ends and you’ve got Class E airspace down to the surface.  If you cross a dotted blue line, that’s Class D and it goes all the way to the surface, i.e., no more Class G.  When I mention the magenta lines, I should probably clarify that these are intended to indicate the floor of Class E airspace because Class G isn’t officially represented on sectional charts.  However, you can use the process of deduction to realize that Class G is below Class E.

This is fine and makes sense if you’re flying in an area that’s relatively flat, but what happens when you’re flying close to the mountains?  I’ll mention when I talk about Class E airspace, but Class E starts everywhere at 14,500-feet above sea level. If you’re flying near a mountain range, you can easily reach 14,500 feet above sea level even though you’re flying 1,200 feet above the ground.  So to sum up this last point, let’s say you start flying from Johnson County Executive Airport in Olathe, KS where the altitude is 1,100-feet above sea level, so your altimeter will read 1,100 when you’re sitting on the ground You take off and head to the west flying at 900-feet above the ground which means your altimeter will read 2,000-feet (1,100-feet MSL + 900-feet AGL).  As you head west, you maintain 900 feet above the ground, but your elevation above sea level will continue to increase.  If you fly far enough, your altimeter could end up reading 14,500-feet MSL even though you’re still only 900 feet above the ground.  At this magical point in time, Class G ends and the controlled airspace of Class E starts.  Whew.  That was a lot of words for something I should have been able to take care of in one sentence!

Even though Class G is uncontrolled airspace, there are still weather minimums that pilots have to adhere to.  You need at least 1 statute mile of visibility during the day and 3 miles at night if you’re flying lower than 10,000-feet above sea level.  If you’re in that mountainous terrain and are higher than 10,000-feet above sea level, you need at least 5-miles of visibility.  If you’re flying lower than 1,200-feet AGL, you simply need to be “clear of clouds”. If you’re above 10,000-feet MSL, you need to be 1,000-feet above, 1,000-feet below, and 1 mile laterally from clouds.  Again, since Class G is uncontrolled airspace, there are no ATC communication requirements to enter the airspace.

A C2 Greyhound taxiing out to release jumpers at 12,000-ft MSL, or Class E airspace.

Class E (again) – Now that I’m finished with my dissertation on Class G, it’s time to come back to the “everywhere else” class of Class E.  I guess I can sum this one up pretty quickly now by saying that if it’s not Class A, B, C, D, or G, then it’s class E airspace.  It’s marked on your sectional by fuzzy magenta circles or dashed magenta lines.  On the outside of the fuzzy magenta circle, Class E starts at 1,200-feet above the ground and extends upwards to 18,000-feet MSL unless, that is, you run into a Class B or Class C “cake layer” first, at which point it becomes that respective airspace until the upper limit is reached, then it becomes Class E again up to 18,000-feet MSL.  Once you’re inside the fuzzy magenta, Class E starts at 700-feet above the ground. When you cross over a dashed magenta circle it means Class E airspace starts at the surface. There aren’t any ATC communication requirements to enter the airspace when flying VFR and there are no airports within Class E airspace that are permanently towered (there is the possibility for a Class E airport to be tower controlled in certain situations like during airshows, sporting events, etc., but once the event ends so to does the tower control.  These rare instances will be communicated via a notice to airmen, or NOTAM).

Your weather minimums are basically the same as for Class G, the notable exception being daytime visibility below 10,000-feet MSL.  In Class G you need 1 mile of visibility and to be clear of clouds.  In Class E, you need 3 miles of visibility and your “standard” 1-5-2 cloud rules exist.  Other than that, Class E weather requirements are then same as for Class G.

So, that’s the basic breakdown on airspace in the US.  There are other things I didn’t mention like military operations areas (MOAs), Victor Highways (federal airways), restricted airspace, etc., for the simple reason that it would have added more length to this post than I wanted to have; definitely more than you would have wanted to read J.  But I will try to do one more thing and develop an analogy to help explain airspace.

Picture an empty fish tank that’s large enough to sit on top of the United States (that’s a lot of fish).  In the large cities, take a huge 3-plus layered blue wedding cake and turn it upside down right on top of that city’s airport.  This is Class B.

Now take a large 2-layer magenta cake (Groom’s cake?) and turn it upside down on top of the large city airports not deemed large enough to get a wedding cake.  This is Class C.

Now take a tall glass and set it over tower-controlled airports that aren’t already covered by a wedding cake or groom’s cake.  This is Class D.

For Class E, I can’t think off hand of a good way to create an analogy, but you can basically just draw circles around the non-towered airports as well as the airports that you’ve already done something to.  (Small, private airstrips don’t get any of the cake or line treatment).

Now that you’ve gotten all of your airports marked, dump in a layer of gravel.  This gravel will fill in everything that’s not occupied by Class B, C, D, or E.  The gravel is your Class G airspace.

Now fill the tank with water.  The water is going to fill all of the space not taken up by cakes, glasses, lines, and rocks.  This is Class E.

Finally, put a lid on the tank to represent Class A airspace from 18,000-feet MSL to 60,000-feet MSL.

So there it is, the not totally all-inclusive beginners guide to starting to understand the basics of the simpler aspects of airspace.

iPhone pic of my first sectional – What types of airspace do you see?


2 thoughts on “All About Airspace – Flight Lesson 16

  1. You should look at the Los Angeles TAC chart to see how strange and confusing these controlled airspaces can get. Then think of having to do your training out of one of the airports in that chart. You would think you’d end up with your IFR ticket when your done.

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