Violations of Controlled Airspace: Special Study 1993

In late 1992 the Bureau of Air Safety Investigation (BASI) noted
a large increase in violations of controlled airspace (VCAs).
Whereas in most of 1991, there had been around 25 such incidents
per month, in December 1991 there were 42 of these incidents and
throughout 1992 BASI received an increasing number of VCA
notifications. The increase in VCAs was of particular concern as it
may have reflected difficulties with the implementation of the
Airspace Management and Air Traffic Services ( AMATS ) changes to
Australian airspace. A VCA is a serious incident because of the
risk of a collision between the intruder and an aircraft under air
traffic control (ATC).