This is a class on Airspace, as it might apply to helicopter operations. Class A airspace will not be addressed. (Not many helicopters go above 18,000.)

Helicopter pilots really do care about airspace. Ok Ok maybe not all helicopter pilots care. However our type of flying frequently takes us into all the different types of airspace. In one flight you could easily enter Class B, C, D, E and G.

The FAA in there infinite wisdom (and that was by no means sarcastic) decided to rename the airspace in the US so it more closely resembles that of ICAO. For new pilots, learning the terminology is no big deal. For those who have been around since helicopters had dirt floors, this transition has been difficult. Those folk should relax because very little has changed. Those who are really having difficulty adjusting are those who probably weren't that familiar with airspace requirements in the first place.

For simplicity's sake, there are only two types of airspace; controlled and uncontrolled. Uncontrolled airspace is Class G, controlled airspace is everything else. As I see it, the major differences between all this airspace are weather and communication requirements. There are other minor differences that cover pilot requirements and aircraft and equipment requirements.

CLASS G

Uncontrolled airspace. Class G airspace can be further divided into three distinct areas:

1. below 1200 AGL
2. above 1200 AGL but Less Than 10,000 MSL
3. above 10,000 MSL but not less than 1200 AGL.

There are no communication requirements in class G. You don't have to talk to a soul. There are times for prudent communication however. Around an airport with a Unicom or CTAF would be such a time. Or maybe in a high density helicopter area like the LA Basin. This is not only prudent for safety, but it is courteous as well.

Below 1200 Feet AGL

For us helicopter drivers, the FAA has offered the most leniency here and also the most opportunity to find our weakness. Below 1200 feet AGL we can operate clear of clouds with an airspeed to see and avoid obstacles. You'll notice that there is no minimum visibility requirement. That was not an oversight. The FAA allows us to operate at this vague criteria because we can adjust our speed all the way down to a hover. This is pretty convenient as long as you can maintain some kind of visual reference.

As I said earlier, this also gives us the greatest opportunity to find our weakness. I'm talking about decisions and judgment. At what point do we say we won't go. Weighing the risks against the goal. Each day is a new challenge to our own judgment. The weather that you felt was acceptable to fly in yesterday is not always acceptable today. However, this vague concept of judgment, holds true for every time we contemplate flying. It just seems that in Class G airspace, your limits are more easily found.

Above 1200 Feet AGL but Less than 10,000

Above 1200 AGL, we must comply with cloud clearance requirements as well as visibility requirements. The standard 500 below, 1000 above and 2000 horizontal plus a one mile minimum visibility daytime and three miles nighttime are what is allowed here. For those of you in the east of the Rockies, there really is a lot of G airspace above 1200 feet AGL. You just have to head west a little.

Above 10,000 Feet MSL but not Less Than 1200 Feet AGL

Above 10,000 feet MSL, but not less than 1200 feet AGL, cloud clearances change to 1000, 1000, 1 mile and visibility minimums increase to 5 miles. Believe it or not there still a lot of places like this that you can get into.

A favorite question I ask during orals is placing the aircraft at 10,300 feet in Class G airspace I come upon a sizable cloud. How far must I avoid this cloud? This question points to the application of different requirements in two different areas of Class G. As the aircraft descends below 10,000 feet to avoid the cloud, the requirements change.

Class G airspace ends at 14,500 feet where Class E Airspace takes over.

CLASS E

Controlled Airspace. Class E is the catch-all name for all controlled airspace that is not specifically around an airport with a control tower. Weather requirements to operate in this airspace below 10,000 feet MSL are the standard 5,1,2 and 3. Above 10,000 MSL it changes to 1000,1000,1 and 5. If the weather is less than that, stay out of there!

As I said, Class E is Everywhere. It can be above 14,500 feet or at the surface. The only time there is a communication requirement is when Class E is surface based and the weather is less than 1000 and 3. Because Class E is controlled airspace, a SVFR clearance will be required to operate under such conditions. The clearance can come from a tower, if they're feeling generous, or more likely than not, from approach control. I say, it can come from a tower, because sometimes surface based Class E is attached to Class D. You've seen this on the VFR Sectional as a magenta dashed line connected to a blue dashed line. It is designed for the safety and convenience of other aircraft conducting instrument approaches. Some towers however, do not recognize that Class E airspace as belonging to them so they will not issue a clearance.

CLASS D

Controlled Airspace. This is the lowest echelon where a tower is operated. The dimensions for Class D are as depicted on the VFR chart. The top of Class D generally goes to 2500 AGL and the MSL altitude is published on the VFR Sectional.

Communication is a requirement. Aircraft must seek permission to enter Class D airspace and should avoid it if there is no intent to takeoff or land. Weather requirements are the standard for controlled airspace. SVFR is authorized if granted by the controlling agency.

CLASS C

Controlled Airspace. The size of this airspace is always depicted. Always look for the altitudes published for each section. They give a minimum and a maximum altitude. If you want to avoid the airspace, stay out of those altitudes. Be Careful to look for changes in altitude. The airspace may be divided in such a way that you may be under the airspace at one point and at the same altitude a few feet to your left or right you are inside the airspace. This can be bad because Communication is a requirement here prior to entry.

CLASS B

Controlled Airspace. The dimensions of this airspace vary from Class B to Class B. They vary as necessary to achieve adequate control of aircraft sequencing into and around these large congested airports. Communication is a definite requirement. As far as weather requirements, the FAA did something smart here to assist the workload of ATC. Clear of clouds with a minimum of 3 miles visibility. Since all aircraft that enter Class B are under positive control using radar, they felt they could cram more aircraft into their airspace by reducing the cloud clearance requirements. This enhances traffic flow (so they tell me).

Quite a few helicopters operate in and around Class B airspace and I have found it very user friendly. We just have to remember ATC's job is to sequence and prioritize aircraft. If we're not a priority don't get bent out of shape. Be specific about your request and if it doesn't interfere with other aircraft, you'll most likely get cleared to do what you want.

CHAMELEON AIRSPACE

You've seen this airspace. It changes depending on if it is day or night. Whether tower is open or closed. Class D airspace can change to Class E or G and Surface Class E can change to Class G. One of the requirements for Class D is of course an operating control tower. If that tower closes, the airspace may change to E or G depending if they still have weather reporting capability and the letter of agreement in the establishment of that airspace. It all gets pretty convoluted as to the specific reasons for the changes. The only absolute place that I have found to see how this airspace changes is in the Airport/Facility Directory.

In Conclusion...

Knowing airspace is important. The criteria for operating in all these different types of airspace was developed for the safety of pilots, passengers, and residents below. Very few missions are worth the lives of anyone of those people. Please don't push the envelope because the FAA's rules are too limiting.

Ok... I'll step off my soap box now. Just remember to review your route of flight (prior to takeoff), noting the type of airspace that you will encounter. The small amount of knowledge you gain from planning, will help your decision making process for the conduct of the mission.