Review of midair collisions involving general aviation ... - Fly Safe!

• A pilot not using his radio to communicate was cited as a possible contributing
factor in one of the aeroplane-aeroplane collisions at a non-towered aerodrome,
with the pilot not making a base broadcast due to congestion on the radio
frequency at the time. In the majority of the other collisions, there was evidence to
suggest that pilots had made the appropriate radio broadcasts. In at least six of the
aeroplane-aeroplane collisions, one or both of the pilots did not hear a radio
broadcast made by the other pilot. Both pilots were not using radios in three of the
aeroplane-glider collisions, and the glider pilot did not make appropriate
broadcasts in another two of the collisions. In another aeroplane-glider collision,
the aeroplane pilot did not broadcast on the glider frequency. 12
• In at least six of the collisions, pilots were provided with and were aware of traffic
information, but it was at least moderately likely that the pilot identified the wrong
aircraft.
• Actions by air traffic control personnel were directly involved in the midair
collision in the Coolangatta control zone in May 1988. Controllers not providing
adequate traffic information probably also contributed to at least three of the
collisions at the major general aviation airports.
• High pilot workload or distractions were cited as a possible factor in at least three
of the collisions. It is also likely that, in many of the other collisions, workload in
the circuit area reduced the time available for searching for unknown traffic.
• Cockpit visibility restrictions would have reduced the ability of at least one of the
pilots to see the other aircraft during some of the later stages for many of the
collisions. For example, on final approach there are usually significant cockpit
visibility restrictions on one or both pilots seeing the other aircraft.
Figure 2: Diagrammatic representation of collision angles involved in collisions not
involving deliberately close flying activities
The diagram does not include collisions with gliders, or collisions where aircraft were flying
deliberately close.
12 The then Bureau of Air Safety Investigation (BASI) has made recommendations regarding the use of radios by gliding
operations. BASI was incorporated into the new Australian Transport Safety Bureau from July 1999.
11