Part 138 Manual of Standards updated to restore rappelling rules


We have amended the Part 138 Manual of Standards to reinstate the ability for non-emergency service operators to conduct rappelling. These provisions existed before the flight operations rules commenced on 2 December 2021.

A man rappelling from a helicopter, with both silhouetted against an orange sky, and the brown dirt beneath them

These amendments are minor or machinery in nature that do not substantially alter existing arrangements.

To see the amended changes visit the Federal Register of Legislation.

Amended changes
MOS provision Problem Change
Paragraph 14.02 (4) (a) Existing words do not use the defined term 'rappelling'. Replace descriptive activity words with the defined term 'rappelling'.
Section 15.01 Unclear explanation to the MOS reader how the Class D external load significant change rule works. A Note has been added to the end of this section explaining that the first conduct of each kind of Class D external load operation is a significant change that requires CASA approval.
Subsection 15.06 (6) CAO 29.11 allowed non-emergency service operators to conduct rappelling, but this aspect of the old rules was mistakenly not included in Part 138. The use of the abbreviation "ESO" has been removed in this subsection, thereby allowing non-ESO to also conduct rappelling.
Section 15.09 The title of this section of the MOS was unclear, making it harder for the reader to identify the purpose of this section. The existing section title has been replaced with “Approvals required for Class C and Class E external load operations.


Subsection 15.09 (4)

This subsection required applicants for a Class C or Class E external load approval to provide CASA with both a detailed risk assessment and a detailed safety case.

These requirements were somewhat identical plus the words used were inconsistent with other similar provisions in the MOS.

This subsection also required applicants to provide CASA with an “indication of how the applicable requirements of this Chapter would be complied with” but this lacked specifics.

The existing paragraph (b) “detailed safety case” has been deleted.

The existing paragraph (a) “detailed risk assessment” has been replaced with “detailed risk assessment and mitigation processes”.

The existing paragraph (c) has been replaced with a new paragraph (b) that states “proposed operations manual content, and, if necessary, training and checking manual content, that includes the operational procedures that enable compliance with the applicable requirements of this Chapter”.

An explanatory Note describes when training and checking manual content might be required.

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