Proposed changes to airspace architecture around Melbourne will lower the control step west of Kilmore from 3500 feet to 2500, forcing aircraft in G airspace closer to rising terrain.
The changes are outlined in an industry consultation document posted to the Aviation Safety Engagement Forum (AVSEF) site last week, and are part of airspace changes being made to accommodate new approaches to Melbourne International once the third runway commence operations in 2031.
According to the document produced by air traffic management consultancy Trax Asia Pacific, the new steps will be necessary to ensure Independent Parallel Runway Operations (IPRO) can be included as part of the Melbourne Third Runway (M3R) system. The current architecture will not provide sufficient CTA protection for Standard Arrival Routes (STARs) proposed.
Changes proposed in the document would result in a section of the CLL 3500 step from Wallan in the East to just west of Monegeetta lowered to 2500, and a section of the CLL 4500 from Kilmore to Rochford lowered to 3500.
Importantly, the airspace has been designed to ensure Kilmore township remains under the 4500 step to protect GA traffic using the Kilmore Gap.
Terrain under the new 2500 step is as high as 1854 feet AMSL, leaving little clearance for aircraft to remain OCTA.
The consultation paper also proposed lowering a section of the CLL 4500 step to the south of Melbourne over Port Phillip Bay in an arc between Werribee South and the border of the Moorabbin CTR.
"These refinements are anticipated to be limited in scope and subject to further technical assessment," the engagement paper states.
"They include increasing the size of the 2500-ft and 3500-ft Class C steps, particularly over Port Phillip Bay and in the northern corridor between Romsey and Kilmore, to ensure adequate protection of the new Runway 16/34 independent parallel operations in accordance with ICAO requirements."
Construction of Melbourne's third runway–16L/34R–is expected to begin in earnest next year, with a projected entry into service of 2031.
The full consultation document is on the AVSEF Victoria webpage, open for feedback until 12 December 2025.