As a balloon pilot, the best thing to do right now as you read this is, name the classes of airspace above you, from lowest to highest.” This is one of the most common questions examiners ask of applicants as part of the oral portion of the practical balloon test. Here are some follow-up questions for you:
Name the visibility, or cloud clearance requirements, of each of the airspaces you just named. The answer to the first question will always end with “E, A,” and that answer could be the total answer.
Here is a review of the classes of airspace, with their requirements for hot air balloon operators:
Class A airspace
Class A airspace starts at 18,000 feet and most hot air balloon pilots will never fly there. VFR flight is not allowed in Class A airspace, and therein lies the answer to the visibility and cloud clearance requirements: there aren't any. IFR-only flight also means that you would need an instrument rating to operate in this space. There is no instrument rating for hot air balloon pilots, so you will only be able to use this space by getting special permission. To get that permission, you will need to have a 2-way aircraft radio to communicate, and an altitude-reporting transponder to allow Air Traffic Control to track your position. As a practical matter, it's rare that hot air balloon pilots fly above 17,999 feet.
Class B Airspace
Only the very busiest airports require Class B airspace designation. This is often described as an upside-down wedding cake space. This shape provides Air Traffic Control the ability to create a steady flow of traffic, funneling aircraft from diverse directions and with diverse destinations into and out of safe spacing that optimizes the airport’s handling capacity. This space functions almost exactly the same as Class A airspace for IFR traffic, but it also allows VFR traffic to use the space simultaneously. The two-way radio communications and transponder requirement are the same as class A airspace. These requirements create an airspace that has all traffic under positive, three-dimensional control, and therefore there is no clearance from clouds requirements. As a general rule, balloons do not freely operate within Class B airspace. Equipment requirements are the same as for Class C airspace; however, due to air traffic congestion, the balloon pilot requesting entry to Class B airspace will likely be denied entry, as ballooning operations inside the Class B airspace constitute a potential traffic conflict.
But legally you can and the FAA prefers you coordinate beforehand, should it become necessary for operational reasons to fly through Class B airspace. The flight should be coordinated at least one hour prior, as provided for by 14 CFR section 91.215. It is permissible, and perfectly legal, to operate a balloon under the lateral limits of the Class B airspace.
When operating VFR, you must still maintain 3 miles’ visibility. The space below the extensions that fan out from the center of Class B airspace often provides airspace you may fly within, that is significantly less restricted. At many locations, determining the dimensions of this space requires careful interpretation of the sectional chart markings and labels.
Class C Airspace Airports that are complex and usually have some level of airline service, or other users that create congestion, become Class C airspace. The basic Class C airspace is a 10-mile diameter cylinder of space surrounding the airport with a second cylinder, 20 miles in diameter, laid on top of it. The radio communications requirement is the same as Class B airspace but the transponder is not required to have altitude reporting capability. Now Air Traffic Control has two-dimensional control of traffic and must rely on pilots to maintain their assigned altitude to insure safe spacing. This dictates a need for cloud clearance, and that clearance is: 500 feet below, 1,000 feet above, and 2,000 feet horizontally. All aircraft operating below 10,000 feet are required to limit their airspeed to 250 KTS. Since no hot air balloon in history has gone over 250 mph... you should be good there. This basic 5, 1, 2 cloud clearance is to allow aircraft below that speed to see and avoid each other. If you remember this 5, 1, 2 separation from clouds, it will always apply when flying below 10,000 feet, with one exception that will be covered in Class G airspace. Minimum visibility remains at 3 miles. And, as with Class B, the airspace underlying the outer ring will have fewer restrictions.
Class D Airspace
We now look at airports that have the lowest level of air traffic still requiring enough control to warrant a traffic control tower. The fundamental Class D airspace is a 10-mile diameter cylinder surrounding the airport. Two-way radio communications are required. The tower controllers now rely on pilots to maintain their assigned altitude and course. The cloud clearance and visibility remain the same as Class C airspace. The size of the class D airspace being much smaller than B or C allows the controllers to visually monitor traffic, compensating for the reduction in electronic tracking. A number of Class D airspaces have control towers that do not operate 24/7. Therefore, at times when the tower is not operating the communication requirement is eliminated. The most common partial schedule is 7:00 AM to 11:00 PM, often providing a morning balloon flight access without a radio. Class D airspace’s upper limit is normally about 2,500 feet AGL, often making it practical to overfly in lieu of obtaining a transition clearance. As a balloon pilot, it's important to use some type of real-time electronic map. Foreflight is a good option to know how close you are to each airspace. If you don't call into a tower before going into the airspace, you can assume you'll be hearing from the FAA.
Class E Airspace
Class E airspace is the space below 18,000 feet comprising the low altitude airway system crisscrossing the country. The number and proximity of routes combine to fill almost all the space below 18,000 feet not designated B, C, or D. This space extends downward to one of three altitudes: either the surface, 1,200 feet AGL, or 700 feet AGL. There are airports without control towers that have precision instrument approaches into them. At these airports, the Class E airspace will extend to the surface. Airports with non-precision instrument approaches will have class E airspace extend down to 700 feet AGL. Elsewhere, the Class E airspace stops at 1,200 feet AGL. Below 10,000 feet the cloud clearance and visibility are the same as C and D. Sectional charts will indicate to you which altitude the Class E airspace extends down to. As you will always be VFR in this space there is no communications requirement. But keep in mind that you may be mixing with VFR and IFR aircraft traffic. Another little quirk of the system is that though you may still be in Class E airspace if you go above 10,000 feet AGL
Class G Airspace
This is the space that you should know the most about because you will likely be spending more time in it than any other. It starts at the surface and, except in rare instances, extends up to Class E airspace (700 feet or 1,200 feet AGL). It is termed uncontrolled airspace. This does not mean you will not meet up with aircraft flying through it. The big change is the reduction of the visibility and cloud clearance to one mile and clear of clouds when below 1,200 feet AGL during the day. There is no control, therefore, no communications requirement. The big challenge is to utilize it and remain at the minimum safe altitudes required by part 91:119.
In Seattle, we fly in class G and E airspace. The class B airspace shelf is at 3000 feet or 5000 feet depending on the route we fly.
Student pilots are prohibited access to Class A and B airspace, with a small exception for Class B airspace. Don’t go there! Because operating a balloon on a tether is considered operations covered by Part 91, all the requirements outlined for controlled airspace apply. For example, you are offered big bucks to tether your balloon in the parking lot of the Forest Hills Tennis Club in Queens, NY. This puts you smack in the middle of one of the busiest Class B airspaces. All the Class B restrictions apply. Any time you are faced with tethering within class B, C, or D airspace, make a call to the controlling facility; explain your proposed operation, and request relief from the requirements. In my experience, this is usually granted, as long as you can get them to understand exactly what you are proposing. Your knowledge of the airspace system can make your flying safer. This is information that you can also use to make your flying more efficient. Sometimes moving your balloon launch site a short distance can put you in airspace that is much less restrictive, without compromising safety. That same knowledge could also keep you from being charged with a violation.
Know The Airspace Alphabet BFA Mag (Contributor Bill Hughes) - Part of the free searchable ballooning database for all balloonists to find information on hot air balloon training.