Airspace & ATC

010 Air LawChapter 3

Airspace classes (summary)

Class	Control	Separation	VFR / IFR
A	IFR only	All IFR	IFR only
B	All traffic	All	VFR + IFR
C	All traffic	IFR–IFR, IFR–VFR	VFR + IFR
D	All traffic	IFR–IFR only	VFR + IFR
E	IFR only	IFR–IFR	VFR + IFR
F	Advisory	IFR–IFR (as practicable)	VFR + IFR
G	Uncontrolled	None	VFR + IFR

Key fact

Class A — IFR only; ATC clearance required; continuous two-way radio; transponder where prescribed.

Key fact

Class C/D — VFR requires two-way radio and transponder (where applicable). Class G — no ATC clearance required for VFR.

Separation minima (typical exam figures)

Situation	Minimum
Vertical (IFR)	1000 ft (below FL290); 2000 ft (FL290 and above)
Horizontal (same direction, same level)	5 NM
Opposite direction	15 min before estimated passing, or 10 NM
Approach (sequencing)	3 NM or 1000 ft

Exam trap

Exam questions often mix ICAO standard vs national variation. Default to ICAO Annex 11 unless the question specifies a particular state’s AIP.

Wake turbulence categories

Category	MTOW
Super (J)	A380 class
Heavy (H)	≥ 136 000 kg
Medium (M)	7 000–136 000 kg
Light (L)	≤ 7 000 kg

Key fact

Wake turbulence separation — behind Heavy: 2 min (or 3 min if same runway / less than 2 NM final). Behind Super: increased separation per local procedures. Caution: wake can persist several minutes in calm conditions.

SSR and transponder

Key fact

Mode A — identity (squawk). Mode C — identity + altitude. Mode S — selective interrogation + data link. 7500 — hijack. 7600 — radio failure. 7700 — emergency.

Reduced vertical separation (RVSM)

Key fact

RVSM between FL290 and FL410 — vertical separation reduced from 2000 ft to 1000 ft. Aircraft must be RVSM-approved and crew RVSM-trained.