Drone Acronyms
What is MAC (Mid-Air Collision) & How Does it Work?
Definition
MAC, or Mid-Air Collision, refers to an incident where two or more airborne objects—such as drones, helicopters, airplanes, or birds—physically collide while flying. In drone operations, MAC is a significant safety concern, especially during inspections, BVLOS (Beyond Visual Line of Sight) flights, or missions conducted in busy or low-altitude airspace. Avoiding MACs is a critical part of responsible drone flight planning and execution.
Usage
MAC risk management is crucial during drone inspections near infrastructure, in urban environments, at emergency scenes, or when flying near other aircraft or drones. Operators use visual observers, onboard detect-and-avoid (DAA) systems, preflight airspace checks, and strict adherence to altitude regulations to prevent mid-air collisions.
Relevance to the Industry
Preventing MACs is essential for maintaining airspace safety and protecting both drone equipment and other airspace users. A collision can cause property damage, injury, or regulatory penalties. As drones become more common in commercial inspections and public safety operations, integrating MAC mitigation strategies is vital for earning public trust, meeting regulatory requirements, and ensuring sustainable growth of drone usage in controlled and uncontrolled airspace.
How Does MAC (Mid-Air Collision) Work?
Preventing a Mid-Air Collision (MAC) involves a coordinated set of practices, technologies, and regulatory compliance steps that keep drones and other airspace users safely separated during flight operations. Here’s how MAC risk management works in drone inspections and broader aerial missions:
Pre-Flight Airspace Assessment
Before launching, pilots check for other airspace users by reviewing NOTAMs (Notices to Airmen), temporary flight restrictions (TFRs), local air traffic advisories, and authorized drone flight zones. Mobile apps and real-time airspace monitoring tools provide updated traffic information that helps in planning a safe flight route.
Flight Planning to Avoid Conflicts
Operators design mission paths that minimize flight near known aerial routes, low-level helicopter corridors, or emergency operations areas. Altitude limits are set according to regulatory standards—such as staying below 400 feet AGL (Above Ground Level) in the U.S.—to maintain vertical separation from manned aircraft.
Maintaining Visual Line of Sight (LOS)
Maintaining unaided LOS is a fundamental way to spot incoming aircraft or other drones early. Visual Observers (VOs) are often deployed to expand awareness, particularly in complex environments like urban inspections or near tall structures.
Onboard Detect and Avoid (DAA) Systems
Advanced drones may include onboard sensors like ADS-B receivers, radar, or computer vision systems to detect nearby aircraft automatically. These systems can alert the pilot or autonomously maneuver the drone away from potential collision courses.
Real-Time Communication and Coordination
During operations near airports, emergency scenes, or high-traffic areas, drone pilots may be required to coordinate with Air Traffic Control (ATC) or a centralized Incident Command System (ICS). Communication ensures that everyone operating in the airspace knows where drones are positioned.
Emergency Procedures for Conflict Avoidance
If another aircraft or drone is detected on a collision path, pilots must be prepared to execute emergency maneuvers such as descending immediately, returning to home, or landing safely in a designated area to prevent a MAC.
By combining vigilant airspace monitoring, technology, procedural discipline, and communication, drone pilots can significantly reduce the risk of mid-air collisions and contribute to a safer shared airspace environment.
Example in Use
“During the tower inspection, the drone team coordinated closely with nearby helicopter traffic to minimize mid-air collision (MAC) risks.”
Frequently Asked Questions about MAC (Mid-Air Collision)
What causes mid-air collisions in drone operations?
Answer:
Lack of situational awareness due to poor visibility, high traffic environments, or distracted piloting.
Flying without proper airspace authorization or during conflicting operations.
Failure of detect-and-avoid systems or reliance solely on onboard cameras without a visual observer.
How can drone pilots prevent MACs during inspections?
Answer:
Conduct thorough airspace checks using apps like LAANC, Nav Canada Drone Site Selection Tool, or local NOTAMs.
Maintain strict Line of Sight (LOS) and use visual observers if necessary.
Equip drones with DAA (Detect and Avoid) technology or transponders in high-risk areas.
Establish clear communication with manned aviation, especially near critical infrastructure or emergency zones.
What happens if a drone is involved in a MAC?
Answer:
Operators are typically required to report the incident to aviation authorities like the FAA, Transport Canada, or EASA.
Investigations may occur, and operators could face fines, license suspension, or equipment seizures.
Safety reviews and retraining are usually mandated before resuming flight operations.
For examples of these acronyms visit our Industries page.
