Aerodrome and heliport safeguarding

Aerodrome safeguarding refers to a set of measures taken to ensure the safety of aircraft operations in and around an airport or aerodrome. These measures are designed to protect the safety and efficiency of flight operations by identifying and mitigating hazards that may affect aircraft during takeoff, landing, or taxiing.

Aerodrome safeguarding typically involves a comprehensive assessment of the airspace and surrounding areas, including land use planning, environmental protection, and infrastructure development. This includes:

• Assessing and managing potential obstructions to flight operations, such as buildings, towers, trees, and other structures that may pose a risk to aircraft.
• Developing and implementing procedures and guidelines for the safe operation of aircraft in and around the airport, such as aircraft parking, taxiway routing, and runway use can also be considered part of aerodrome safeguarding.
• Coordinating with local authorities, landowners, and other stakeholders to ensure that aviation operations are integrated safely and efficiently into the surrounding community.

Overall, aerodrome safeguarding is critical for ensuring the safe and efficient operation of aviation activities, while minimizing the impact on the environment and complying with regulatory requirements.

ICAO Annex 14 Volume I provides guidance on the establishment of protection areas (or Obstacle Limitation Surfaces) around the aerodrome to ensure the safety of aircraft operations. The objective of these surfaces is to define the airspace around aerodromes to be maintained free from obstacles to ensure the safety of aircraft operations and to prevent that aerodromes become unusable.

These surfaces are, among others:

• Inner horizontal surface (IHS): This is a horizontal surface located at a fixed distance above the runway, and it extends outwards from the runway centerline. It provides clearance for aircraft taking off and landing, and it is designed to protect aircraft from obstacles within this area.
• Conical surface: This is a three-dimensional surface that extends upwards and outwards from the end of the IHS. It is designed to protect aircraft during the initial climb-out and approach phases of flight.
• Transitional surface: This is a three-dimensional surface that connects the conical surface to the outer horizontal surface. It is designed to provide clearance for aircraft during the intermediate phases of flight.
• Outer horizontal surface (OHS): This is a horizontal surface located at a fixed distance above the aerodrome, and it extends outwards from the end of the transitional surface. It is designed to protect aircraft during the final approach and landing phases of flight.
• Take-off climb and approach surface: An inclined plane or combination of planes following and preceding the threshold, respectively.

Flight procedures to/from an airport can be assisted by instrument navigation aids. These instrument flight procedures require defining protection areas intended to safeguard an airplane from collision with obstacles when flying on instruments. ICAO Doc. 8168 Volume II specifies the size and dimensions of these obstacle-free areas for the approach- (including missed approach), departure- and visual maneuvering (circling) procedures.

The signal in the service volume for all CNS facilities should be protected from unacceptable interference, to ensure a safe and efficient operation of aircraft. In order to achieve this, each type of facility must have its own safeguarded surface whose dimensions are dependent on the facility type.
As a reference, ICAO Annex 10 is the basis for all aeronautical telecommunication equipment, including installation and operation. In terms of protection of the signal from interference due to terrain and manmade objects, ICAO EUR Doc.015 is used as a reference to define and analyse the CNS safeguarding surfaces.