Safety in the vicinity of non-towered aerodromes - Australian ...

At non-towered aerodromes, circuits are conducted at different heights depending on
the performance of the aircraft (Figure 12). The purpose of prescribed circuit heights
is to separate fast moving aircraft from slow moving aircraft in the interests of
situational awareness and separation.
Further recommendations about circuit entry and height procedures are provided by
CASA in CAAP 166-1.
Figure 12: Standard circuit heights depend on aircraft performance since 3 June
2010
Source: adapted from CASA, 2010a; Department of Transport and Regional Services, 2005
There were 61 conflicts between 2003 and 2008 involving aircraft operating in a
circuit, including the occurrences discussed earlier where entering aircraft conflicted
with other aircraft established in the circuit. The most common types of conflict were:
• aircraft head-on in the circuit (n=20)
– due to an aircraft contravening the circuit direction (n=13)
– an aircraft on final approach on a runway conflicting with an aircraft on upwind
for the reciprocal runway (n=7).
• conflicts between aircraft on base and on takeoff or final approach (n=14)
• enroute aircraft crossing the aerodrome and descending into the circuit level
inadvertently (n=7)
• reduction of separation between aircraft following each other in the correct circuit
direction (n=6)
• reduced vertical separation between aircraft at different circuit heights (n=4).
Enroute
Only about 20 per cent (n = 169) of occurrences at non-towered aerodromes involved
aircraft that were enroute in the vicinity of the aerodrome (either transiting, or
manoeuvring within 10 NM), and were at a height that could have conflicted with
operations at that aerodrome.
When enroute, CAR 166 recommends that pilots make a broadcast where they intend
to fly through the vicinity of a non-towered aerodrome (but not land), either within
10 NM, or at a height over the aerodrome which could conflict with operations.
- 48 -