New multi-part AC for all-weather operations at aerodromes

This consultation asked people for feedback on a new draft multi-part advisory circular (AC) on all-weather operations (AWO) at aerodromes. This multi-part AC is intended to update and replace existing AC 139-19 v1.0 - All-weather operations at aerodromes. The consultation period ran from 13 February to 12 March 2024.

About this consultation
The original AC 139-19 was issued in May 2016. It cross-referred extensively with the version of the Part 139 Manual of Standards (MOS) (Aerodromes) in use prior to the post-implementation review of Part 139 of CASR. With the release of a new and current Part 139 MOS, much of that cross-referencing became invalid.

To ensure accuracy and relevance, we reviewed the AC and updated the cross-referencing. We also made some small changes to ensure that the AC provided guidance to assist operators of non-controlled aerodromes that support AWO.

The consultation asked respondents to give feedback on the new AC to ensure proposed guidance is suitable, clear and will work as intended.

In total, there were 9 respondents to the consultation ranging from the national air navigation service provider – Airservices Australia, the Bureau of Meteorology, a specialist organisation in airport operations, staff training and management, an instrument flight procedure specialist and several individuals. Of the respondents, 5 consented to having their responses made public and 3 requested their submissions be confidential.

Summary of feedback
Three respondents provided detailed submissions. These submissions included feedback about unclear or inconsistent advice within the document, insufficient coverage of meteorological aspects, and references that appeared to oblige operators of non-controlled aerodromes to support AWO. The submissions from these respondents together with CASA's feedback/disposition are separately attached to this summary of consultation (SOC).

A respondent said CASA should provide all-weather operating minima specific for helicopters. These minima should recognise the unique capability of helicopters (* see below) compared to fixed wing aircraft, and allow helicopters to fly to lower minimums and have less minimum visibility requirements.

One respondent said the standards should allow a local competent observer for example, a town fire service, ambulance, police, or grounds person to be appointed to record automatic terminal information service (ATIS)-type information to be transmitted on a common traffic advisory frequency (CTAF). Another expressed concern about occurrences of departures and arrivals at uncontrolled and uncertified aerodromes in conditions well below the IFR minima. The respondent said the AC should stress that the AC guidance does not imply an ability to use an alternative set of criteria for unauthorised operations.

Finally, a respondent recommended that the AC includes guidance on instrument flight procedure design aspects relevant to AWO.For example: Lower operating speeds and ability to descend more slowly.

* For example: Lower operating speeds and ability to descend more slowly.

Next steps
We appreciate the feedback provided by respondents. For the detailed submissions, we included Annexes (* see below) to this SOC with those submissions and our response or disposition against each specific comment. We have also assessed all other responses to this consultation.

As a result of feedback, we have made a number of changes to the AC. In particular, we included guidance on meteorological and instrument flight procedure design aspects relevant to AWO. We have also clarified the guidance for aerodrome operators, particularly of non-controlled aerodromes, particularly to identify when the AC has relevance (for example when an aerodrome has an instrument flight procedure or is supporting take-off operations in visibility conditions less than 800 m).

Regarding the comment about appointing local competent observers to record ATIS information or equivalent, we consider that provision already exists through the UNICOM standards in Chapter 22 of the Part 139 MOS. However, we have added guidance within the AC in the section on aeronautical information to ensure this is recognised.

Concerning pilots conducting unauthorised operations in poor weather conditions, we have reviewed the AC and believe it does not encourage deviation from flying regulations or from safe flying practices. Accordingly, we believe no changes are necessary.

We now believe the AC will be fit for purpose  for providing best-practice guidance on AWO. Our next steps will be to finalise the draft AC and to publish it at the earliest opportunity.

* Annexes:
A.  Airports Plus submission with CASA response.
B.  Airservices Australia submission with CASA response.
C.  Bureau of Meteorology submission with CASA response.