New TSI Act and ATSB Stabilised Approach Criteria

New TSI Act and ATSB Stabilised Approach Criteria

Transport Safety Investigation Regulations 2021, effective from January 1, 2023, mandated reporting for aircraft incidents in Category A operations with passengers or medical transport. A recent investigation by the S&T team identified disparities in stabilised approach criteria among Australian operators.

Australia's mandatory ATSB reporting requirements were altered on 1st January 2023 with an introduction of the Transport Safety Investigation Regulations 2021 (TSI Regulations: These Regulations established four aircraft operation categories with specific RRM incident reporting requirements.

Category A operations, encompassing passenger and medical transport operations (and repositioning flights prior to conducting a substantive Category A operation), necessitate an RRM submission for any aircraft incident, including unstable approaches as defined by ATSB’s criteria. These criteria can be found on ATSB’s website under Aviation reporting requirements (Aviation reporting requirements | ATSB), and are now also included in AIP ENR 1.14-19 (

The S&T team investigated and compared stabilised approach criteria among various Australian Category A operators and found discrepancies not only between ATSB and operators’ criteria for stabilised approaches but also some discrepancies between ATSB and ICAO standards, with ATSB's approach being more prescriptive. For instance, ATSB lacks provisions for unique approach conditions or abnormal situations necessitating a deviation from any elements of a stable approach criteria, and it mandates a criterion for a circling approach that ICAO does not include in their criteria. Conversely, ICAO adopts a more flexible, recommendatory approach, allowing operators to tailor criteria to their specific operations. There is also a difference in the reference point between ATSB and ICAO (ground level vs airport elevation respectively).

Furthermore, discrepancies between ATSB's and operators' criteria may lead to confusion regarding RRM reporting requirements, particularly when operators have more stringent criteria for determining a stable approach. Clarification is needed on whether deviations from operator criteria warrant RRM submission, especially if a go-around is initiated due to an unstable approach according to the operator's SOPs (i.e. ATSB would not require an RRM according to their published criteria).

Areas for ATSB review include incorporating provisions for unique approaches, defining a correct flight path, revising criteria for heading and pitch changes, considering various reference speeds, clarifying terminology used and criteria for power/thrust settings and checklist completion. Additionally, ATSB should evaluate the relevance of certain criteria like Cat II or III instrument approaches and consider approaches other than ILS, as well as investigate standardizing ground reference points and minimum stabilisation heights based on operation types.

The AFAP suggests a collaborative review involving ATSB, CASA and industry representatives to address these differences, remove existing ambiguity and ensure better alignment with international standards for safer aviation operations in Australia.


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