Safe planning and conduct for aerodrome works – Draft Advisory Circular 139.C-15 v1.0

This consultation sought feedback on draft guidance regarding the safe planning and conduct of aerodrome works. Aerodrome works refers to any construction or maintenance on or near an aerodrome's movement area that could create hazards or limit normal aircraft operations.

The consultation opened on 25 September and closed on 19 October 2025.

Draft Advisory Circular (AC) 139.C-15 replaces AC 139.20 on this topic, as it no longer aligns with the Part 139 (Aerodrome) Manual of Standards (MOS).

The purpose of the AC is to provide guidance and information to support aerodrome operators and those involved with the planning and conduct of aerodrome works. Control of work activities ensures hazards and risks to the take-off, landing and ground manoeuvring of aircraft are appropriately managed.

This AC:

• includes additional information to consider when developing method of working plans (MOWP)
• introduces information for NOTAM authorised persons to consider when drafting NOTAMs
• provides additional information on marking, marker and aerodrome lighting requirements
• includes additional information when considering temporary reduced length runway operations and temporarily displaced thresholds.

A summary of the feedback and overview of the main themes that emerged from the consultation responses is provided below.

In total, there were 12 responses to the consultation:

• 4 airlines, aircraft operators, pilots and pilot advocate agencies
• 6 aerodrome operators, support specialists and consultants
• 2 Government, air navigation service provider (ANSP) and/or regulators.

Of the respondents who made written submissions, 8 consented to having their submissions made public and 4 requested confidentiality.

All respondents supported the introduction and content of the advisory circular.

However, some concerns were expressed about the length of the document, repetitive content, duplication of information from other ACs and complexity of information contained in illustrations and diagrams.

Key feedback
The feedback was focused on the aerodrome operator's level of industry collaboration, hazard identification and risk management. The need to ensure appropriate stakeholder identification and timely engagement was emphasised.

The need for guidance to suit the range of aerodromes and their supporting industry was another key theme in the feedback.

Further information about feedback received on each section of the AC is below.

Introduction
Feedback regarding the introduction was that it states the purpose well but could be strengthened by explicitly linking good planning and communication to preventing hazards and pilot confusion. One respondent suggested linking the guidance in the AC to international best practice.

Concern was expressed that the introduction was too wordy, and repetitive.

CASA response:
We reviewed the introduction to make it more concise, focussing on ensuring aerodrome works are not a hazard to aircraft operations.

Aerodrome works alternatives and considerations
Responses identified the need to ensure advice included the ability to scale activities according to the needs of the aerodrome operator, and the industry they intend to support.

Linking the AC to advice provided by the International Civil Aviation Organization (ICAO) and the European Aviation Safety Authority (EASA) was suggested.

CASA response:
We updated the section with a focus on the Australian aviation safety standards with consideration of information provided by ICAO, EASA and other aviation safety regulators. A flowchart was added to assist with decision making.

Planning of aerodrome works
The ability to scale aerodrome works to the nature of works being performed and restriction to aircraft operations was supported by the responders, but the inability to scale method of working plans (MOWP) was questioned.

One response included a suggestion to further link detail in the AC to ICAO PANS-Aerodromes (Doc 9981).

There was a high degree of support for CASA's statement that there is less risk to aircraft operations and people when a runway is temporarily closed rather than a temporary reduction of operating length of a runway.

CASA response:
We updated the AC to include examples on the purpose of a MOWP and improve linkages to other CASA ACs that address hazard identification and risk management.

Promulgating information on aerodrome works
Questions were raised around details to be included in NOTAM, the minimum time required for NOTAM to be published, and alignment with ICAO Annex 15. An increased focus on the use of AIP-SUPs was suggested.

CASA response:
We have increased focus on the use of AIP-SUPs and aerodrome operator provided information on aerodrome works. Significant effort was placed on improved NOTAM related to temporarily reduced length runway operations and temporarily displaced thresholds. The AC introduced new NOTAM templates.

Aerodrome markings, markers and lighting
One respondent identified practices related to the superseded AC 139.20(0) had changed in this AC regarding the marking and lighting of temporary runway end and runway strip ends.

Concerns were raised that images and illustrations were too complex, contained too much information and were difficult to interpret. This included concerns where visual aids were determined to be significant contribution to events.

CASA response:
CASA considered the response regarding AC 139.20(0) and identified the existing practices used to define marking and lighting of temporary runway and runway strip ends is not consistent with the Part 139 MOS. Information in AC 139.C-15 ensures practices are aligned with the Part 139 MOS. Images and illustrations regarding aerodrome markings, markers and lighting were reviewed and amended to address the concerns.

Reduced length runways and temporarily displaced threshold
One respondent identified the guidance in the draft AC to be complex and difficult to interpret. Outcomes from previous ATSB reports were identified by respondents. Linkages to ICAO PANS-Aerodromes (Doc 9981) was mentioned.

CASA response:
We reviewed ATSB reports and reports from other international investigative authorities. Guidance was reconsidered, and information in the AC has been updated to ensure the reader can correctly interpret the information.

Control of works on the movement area
Feedback on the guidance for the control of works on the movement area was positive. One respondent recommended the introduction of ICAO guidance on runway incursion prevention in the AC.

CASA response:
We updated the AC to include additional ICAO guidance.

Appendices
Respondents supported the information provided in the appendices but reported that images and illustrations were too complex and difficult to interpret.

CASA response:
The appendices were reviewed and simplified. Additional guidance to aerodrome works related NOTAM were included in the AC.

Summary of feedback
Feedback on the draft AC was generally supportive, with areas of disagreement largely stemming from reliance on superseded guidance and now-redundant standards.

A common theme across the responses was that the draft AC is overly wordy, and complex. Concerns were also raised about the complexity of topics covered in a single AC.

Several respondents raised the need for consistent published information and visual aids during aerodrome works.

The responses to this consultation were greatly appreciated and where appropriate the content of the AC was updated, improving the quality of the guidance material.

Images and illustrations were updated based on the feedback provided, and input from the National Runway Safety Group (NRSG) Displaced Threshold Runway Works Working Group (DTRW WG).

Next steps
CASA will publish AC 139.C-15, incorporating feedback received through the consultation process. CASA will use the feedback to inform future amendments of AC 139.C-15. Information in AC 139.C-15 that is better located in other ACs will be removed with linkages between the ACs provided to support the reader. These other ACs include:

• AC 139.A-03 application aerodrome standards
• AC 139.C-01 aerodrome manual
• AC 139.C-02 aerodrome personnel
• AC 139.C-05 aeronautical information reporting validation
• AC 139.C-13 apron safety management
• AC 139.C-14 airside vehicle control
• AC 139.C-18 aerodrome emergency planning
• AC 139.C-26 safety management systems for aerodromes
• AC 139.C-27 risk management plans-aerodromes.

A future review of AC 139.C-15 will further develop relationships with these other CASA ACs.