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

2 METHODOLOGY
This study is based on the analysis of occurrences reported to the Australian Transport
Safety Bureau (ATSB) for the 6-year period 1 January 2003 to 31 December 2008.
2.1 Data sources
Occurrence data
The occurrence data was sourced from the ATSB aviation occurrence database known
as SIIMS (Safety Investigation Information Management System). A search of the
SIIMS database was conducted to identify occurrences involving operations into or
near:
• non-towered aerodromes
• aircraft landing areas (ALAs)
• other landing areas in Australia, her territories, and territorial waters
• at which Mandatory Broadcast Zone (MBZ) procedures applied or Common
Traffic Advisory Frequency (CTAF/CTAF(R)) was used, between 1 January 2003
and 31 December 2008.
This search applied to all aircraft registered in Australia (on civil/VH-, military, and
recreational registers) and foreign registered aircraft.
The majority of the reporting period was subsequent to the introduction of the
Transport Safety Investigation Act 2003 (TSI Act) on 1 July 2003, and many of the
occurrence types extracted are immediately reportable matters (IRMs) under the TSI
Act. However, it was determined that the lack of specified reportable matters under
the previous Air Navigation Act 1920 legislation was unlikely to have had a
significant influence on the occurrence types reported. It has been observed in a
number of ATSB investigations and research studies that the number of occurrences
reported to the ATSB since 1 July 2003 has increased significantly due to the
improved reporting requirements of the TSI Act.
The extracted occurrences were reviewed and further sorted into the sub-categories
presented in this report. In particular, safety factors were coded for each occurrence in
terms of the type of pilot and/or air traffic service error that was the primary
contributor to the occurrence. The error types defined were:
• Information errors – individual actions that result from a failure to perceive
something, perceiving something incorrectly, or by not understanding the situation
correctly (i.e. situational awareness problems, and visual or other perceptual
illusions).
• Action errors – actions that deviate from the individual’s plans. These include
error types commonly termed as ‘skill-based’ slips and lapses. Actions involving a
lack of precision during continuous control of an aircraft are also deemed to be
action errors (e.g. attempting to, but not succeeding in manually maintaining a
target speed or altitude).
• Decision errors - individual actions that result when an individual’s plans are not
adequate for the situation.
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