Airspace Protection

Under the Regulations, an airport’s prescribed airspace includes the airspace above:

• the airport’s Obstacle Limitation Surfaces (OLS), and
• the Terminal Instrument Flight Procedure Obstacle Protection (TIFPOP) surfaces (previously known as Procedures for Air Navigation Services – Operations (PANS OPS)), and
• any additional declared airspace made by instrument.

The OLS is designed to provide protection for aircraft flying into or out of the airport when the pilot is flying by sight. The TIFPOP surface is designed to safeguard an aircraft from collision with obstacles when the aircraft’s flight may be guided solely by instruments, in conditions of poor visibility.

Essendon Airport Pty Ltd design, manage and maintain the OLS for Essendon Fields Airport.

Airservices Australia design, manage and maintain the TIFPOP surfaces for Essendon Fields Airport

Primary vs Secondary surfaces

Some surfaces are treated as Primary (more critical phases of flight) and others as Secondary; applications that intrude into primary airspace are more restricted.

Primary Surfaces

Aircraft operating in primary airspace are configured for, and engaged in, critical stages of flight and cannot readily or safely manoeuvre to avoid obstacles. Intrusions into primary airspace therefore generally present an unacceptable impact on the safety, efficiency or regularity of air transport, hence the need to maintain primary surfaces as obstacle free surfaces to the extent possible.

As such, the Regulations prohibit applications to carry out any intrusion into primary airspace that is not temporary. Furthermore, the Regulations specify that an application to carry out a sensitive controlled activity (an activity carried out in relation to primary airspace for an airport) may only be permitted in certain circumstances as detailed in section 13(4) of the Regulations.

Primary surface for an airport includes:

• The TIFPOP surface for the airport; or
• Any of the following types of OLS for the airport:
  • Approach surface
  • Inner approach surface
  • Transitional surface
  • Inner transitional surface
  • Baulked landing surface
  • Take-off climb surface
• A surface declared to be a primary surface for the airport in a declaration made under section 9 of the Regulations.

Secondary Surfaces

Aircraft operating in secondary airspace are configured for and engaged in operations that provides a degree of flexibility to adapt to the obstacle environment. However, obstacles intruding into this airspace may present a safety risk and as such, an assessment is required to identify if the proposed intrusion would be hazardous and/or if any potential risks to aviation safety can be managed or mitigated. Secondary surfaces have a wider range of controlled activities that can be approved under the Regulations.

Secondary surface for an airport includes:

• Any of the following kinds of the OLS for the airport:
  • Outer horizontal surface
  • Conical surface
  • Inner horizontal surface.
• A surface declared to be a secondary surface for the airport in a declaration made under section 9 of the Regulations.

Note on chart terminology:

Existing charts published under the earlier framework remain valid after commencement of the 2026 Regulations; where older charts refer to ‘PANS OPS’, these should be read as TIFPOP under the 2026 terminology (the terminology change does not change the extent of the prescribed airspace).

A controlled activity is an activity that would result in an intrusion into prescribed airspace, and it cannot be carried out without approval.

Controlled activities can include (examples):

• Long term activities including structures, such as buildings, intruding into the protected airspace;
• Short term (no longer than 3 months) activities such as cranes intruding into the protected airspace;
• Any activities causing intrusions into the protected airspace through glare from artificial light or reflected sunlight, air turbulence from stacks or vents, smoke, dust, steam or other gases or particulate matter.

Section 26 of the Regulations provide that the Secretary of the Department may delegate certain functions and powers to delegates from the airport operator company, including to approve or refuse applications to carry out controlled activities and to impose conditions on an approval.

The Regulations also distinguish between two types of activities:

• Temporary controlled activities:
  • The activity is not expected to continue longer than 3 months, or
  • The activity is not intended to remain in place permanently and can be readily dismantled or removed.
• Permanent controlled activities: Anything else

If a building authority receives a proposal for a building activity that, if undertaken, would constitute a controlled activity; it must give notice of the proposal to the airport operator. Failure to do so is an offence under Section 186 of the Airports Act 1996 (50 penalty units – currently $16,500).

Additional information on Protection of Airspace at Leased Federal Airports can be found on the Department of Infrastructure’s website.