Controlled Airspace Overview

For your Pre Solo Exam you need to understand this content, especially if flying in or near controlled airspace. The majority of any exam questions will come from the next lesson on Class E and G.

Australian Airspace can be divided into controlled airspace and uncontrolled airspace plus prohibited, restricted and danger areas (PRD).

Controlled Airspace has Controlled Area’s (CTA) and Control Zones (CTR) . On a VTC chart the area which is lowest and immediately around an airport is the CTR,indicated by a dotted blue line. Most other areas are CTA with solid blue lines.

Controlled airspace falls into two main categories that we are concerned with:

  1. Civil CTR – Class C and D
  2. Military – Class C unless otherwise advised

Civil CTR generally works outwards and upwards from major airports like an upside down wedding cake. This allows air traffic control (ATC) to have large faster aircraft come in from altitude, hold them above if necessary and us smaller aircraft to fly underneath their approach and departure paths.

class-airspace-3

Each section has upper and lower limits in this case shown by lines

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Seen below, different Classes have different purposes. Class A is used to provide separation of high speed pressurised aircraft while cruising between airports. Class A is too high for our aircraft so we are not concened with it.

Class E is a transition layer where the faster jets and turbo props climb and descend and some of the smaller aircraft cruise between airports. Class E has fairly strict requirements due to this and comes down to 8500 feet in many places. We can fly in class E, but must hold correct cruising levels, have a working radio, radio endorsement and certain types of transponders.

Class C and D are used to control traffic close to busy airports. Class C has guaranteed radar coverage and is used at the major airports. Class D might use radar, but generally uses radio and binoculars to separate aircraft.

airspace-classes

The maps pilots use are topographical, not side on profiles, so these levels are described by the Lower Limit (LL) for each class of airspace. Below is part of the Coffs Harbour Visual Terminal Chart (VTC), showing these LL references for the various Class airspaces.

airspace-ll

The above diagram can be translated to look like the diagram below. CTA gets wider as it goes up to allow for arriving and departing aircraft to approach safely within CTA. This also allows VFR aircraft to fly underneath the CTA except for within 7nm of the airport.

class-airspace-3

 

The airservices website has good descriptions of the classes of airspaces and should be checked every 6 months or so for changes. Google search air services classes of airspace.

As of June 2022 Air Services states:

Class A: This high-level en route controlled airspace is used predominately by commercial and passenger jets. Only  IFR flights are permitted and they require an ATC clearance. All flights are provided with an air traffic control service and are positively separated from each other.

Class C: This is the controlled airspace surrounding major airports. Both IFR and VFR flights are permitted and must communicate with air traffic control. IFR aircraft are positively separated from both IFR and VFR aircraft. VFR aircraft are provided traffic information on other VFR aircraft.

Class D:  This is the controlled airspace that surrounds general aviation and regional airports equipped with a control tower. All flights require ATC clearance.

Class E: This mid-level en route controlled airspace is open to both IFR and VFR aircraft. IFR flights are required to communicate with ATC and must request ATC clearance.

Class G: This airspace is uncontrolled. Both IFR and VFR aircraft are permitted and neither require ATC clearance.

Note: At towered airports the class of airspace may change subject to the time of day.