In Work Health Authority v Outback Ballooning Pty Ltd [2019] HCA 2, a majority of the Full Court of the High Court confirmed that Commonwealth aviation laws are not inconsistent with State and Territory work health and safety legislation, therefore no constitutional invalidity arose.

The decision in this matter concerns a fatality which occurred on 13 July 2013, when a hot air balloon passenger sustained fatal injuries when she was pulled into the balloon's inflation fan by her scarf.

In this case, Outback Ballooning argued that the Commonwealth aviation law covers the field and deals exhaustively with the 'prescription and enforcement of the standards of safety in the conduct of air navigation or air operations' in Australia. If this were correct, the implication would be that s 109 of the Constitution would render State and Territory work health and safety legislation invalid, to the extent of the inconsistency.However the Work Health Authority successfully argued that the decision of the Full Federal Court – which held that there is an indirect inconsistency between the commonwealth aviation law and State and Territory work health and safety law – is incorrect.

In their joint judgment, Chief Justice Kiefel, and Justices Bell, Keane, Nettle and Gordon found that the federal Civil Aviation Act (CA Act) is intended to 'operate within the setting of other laws' including the federal model Work Health and Safety Act, and State and Territory legislation enacted to follow the federal model law.

Importantly, their Honours held that '[i]t could hardly be suggested that when [the Model Work Health and Safety Act] was enacted the legislature intended that it would be read down to accommodate the CA Act' and that the CA Act was 'designed to operate within framework of other State, Territory and Commonwealth laws'.

While the majority agreed that the CA Act did in fact regulate almost every activity covered by an aircraft operator, including pre- and post-flight activities, their Honours held it is clear that the obligations under that Act do not exclude other laws which require duty holders to exercise due care in the conduct of air operations.

Briefly, in other single-Judge decisions:

• Justice Gageler held that while a large area of the CA Act operates to the exclusion of State and Territory laws, the provisions requiring the exercise of reasonable care and diligence in the operation of aircraft did not fall within this area of exclusive operation; and
• Justice Edleman, in dissent, found that the CA Act and the Northern Territory's work health and safety law did overlap, and therefore the latter was invalid.