Airspace Classes, Controlled Aerodromes and CTAF

Airspace class describes the traffic environment

Airspace class is the first clue to what kind of aviation environment surrounds the operating site. Controlled airspace is managed by air traffic services. Non-controlled airspace still has rules, traffic patterns, radio frequencies and other aircraft.

For RPA planning, the point is not to memorise every service detail from crewed aviation. The point is to recognise when the operation has moved from a simple open-area job into an airspace decision that needs a chart, current publication, approval check or radio consideration.

A fictional side-on cross-section of airspace, not to scale and with no altitudes. Class G, non-controlled airspace, fills the space from the ground. Around a controlled aerodrome on the right, a stepped Class C or D control zone reaches the ground near the aerodrome and has higher bases further out. Class E sits above the lower airspace, and Class A is high-level controlled airspace at the top. A remote pilot launches a drone in an open area in Class G; a dashed line rises from the drone through E and A, showing controlled airspace above a site that looks open on the ground. Buttons highlight one class at a time or move the site next to the aerodrome, inside the control zone.

• Class A is high-level controlled airspace and is not a normal RPA operating environment.
• Class C and Class D commonly matter around controlled aerodromes and control zones.
• Class E can sit above lower-level airspace and still affect the wider airspace picture.
• Class G is non-controlled airspace, not rule-free airspace.

Controlled aerodromes change the approval question

A controlled aerodrome generally has an operating air traffic control tower. Around those aerodromes, RPA operations may be affected by control zones, approach and departure paths, movement areas, height limits, airspace authorisations and operator-specific approvals.

CASA's current public guidance identifies several situations that require authorisation, including operations above 120 m or 400 ft AGL, operations within 5.5 km or 3 NM of a controlled aerodrome, operations over a controlled aerodrome movement area, and operations in the approach or departure path of a controlled aerodrome.

That wording must be checked against the current CASA page and any operator approval before flight. In the study guide, the durable lesson is the decision habit: do not treat controlled aerodrome proximity as just another map symbol.

Two schematic aerodromes seen from above, north up. Left, a controlled aerodrome: first the control tower pulses with the question 'Tower operating?'; then a 3 nautical mile ring and the approach and departure paths off each runway end are drawn; then 'Approval?' is stamped next to a drone site inside the ring. Right, a non-controlled aerodrome using a CTAF: a left-hand circuit is drawn around the runway, a light aircraft flies the circuit broadcasting its position, and the remote pilot's radio question appears: 'Monitor or transmit?'. Finally a shared label reads 'Brief before launch'. Back and Next buttons step through each check.

• Identify whether the aerodrome is controlled and whether the tower is operating.
• Check the control zone, approach/departure paths and movement area.
• Confirm whether the ReOC, chief remote pilot and individual remote pilot have the required approval pathway.
• Record the decision source, date, time and any approval reference in the job pack.

Read the Controlled airspace, towers, ATIS and transponders transcript

CTAF does not mean casual

A non-controlled aerodrome is normally in Class G airspace. It may use a Common Traffic Advisory Frequency so aircraft can broadcast position and intentions. That environment can still be busy, especially near circuit areas, training operations, agricultural operations and helicopter activity.

For remote pilots, CTAF awareness is about building a traffic picture. If the operation requires radio communication, the crew must have the right qualification and equipment. If it does not, the pilot still needs a practical method to maintain separation, keep VLOS and respond to crewed aircraft.

• Know the aerodrome location, runways and circuit direction where published.
• Know the frequency and whether the crew will monitor or transmit.
• Brief observers on approach/departure paths and likely circuit traffic.
• Land or hold clear early if crewed aircraft activity creates uncertainty.

VLOS and altitude do not replace the airspace check

Staying under 400 ft AGL and maintaining visual line of sight are core RPA habits, but they do not automatically make every location available. Aerodrome proximity, controlled airspace, restricted areas, danger areas, temporary NOTAM activity and operator approvals still matter.

A useful planning sentence is: where is the RPA in three dimensions, what published aviation information applies there today, and what authorisation or communication is required before launch?

The practical output is a go/no-go airspace decision

A good airspace check produces a decision the crew can explain. It says what airspace was checked, what aerodromes or PRD areas were nearby, what NOTAMs mattered, what approval pathway applied, and what operational limits were briefed.

If the answer depends on a current source, include the source. If the answer depends on an approval, include the approval. If the answer depends on radio, include the frequency and qualification assumption.

Practice Questions