Sharing the Skies Safely

An Overview of Unmanned Traffic Management

Source: FAA Safety Briefing, May/June 2021
By: Peter Sachs

Picture this: It’s 2030, and your flying club has a fully electric plane you can take on $100 hamburger runs. Many of your neighbors have electric cars, and you notice delivery drones overhead at least once a day. But when you climb into the cockpit for that hamburger run, how do you know whether there are any unmanned aircraft systems (UAS) in your path? That needs to be just as seamless as ordering your takeout dinner with the drone delivery option. The traffic page on your multi-function display (MFD) or your tablet includes a few more icons representing UAS, color-coded to differentiate them from other manned aircraft nearby. Don’t worry, there are advanced algorithms running in the background that only show you the closest UAS that may be a collision risk, with plenty of time for you to change course. Many other UAS aren’t pictured — not only because that would fill your screen with hundreds of icons, but because those vehicles know about you, and are proactively changing their trajectories so that you never have to worry about them.

Does this sound like science fiction? Maybe you’re breaking out in a sweat thinking about how much those avionics upgrades will cost. But many of these ideas already exist, and they’re built on existing technology that has been demonstrated in the real world. Most likely, low-cost software and receiver updates will be all that you need to worry about. The glue that enables this kind of situational awareness is called UAS Traffic Management, or UTM.

The Future That’s Here Now

UTM is one of the crucial ingredients for enabling these types of missions. Think of everything you do as a pilot on a typical VFR flight: preflight briefings and walk-arounds, reviewing your charts and NOTAMs, checking the weather — and that’s before you even start the ignition. You perform a runup, maybe activate your flight plan. Even if you’re just flying to pick up a hamburger, you’ve got a route in mind that avoids terrain that’s too high and gives you a view of your favorite landmarks. Of course you’re always scanning for traffic, and as you approach your destination, air traffic controllers give you a landing sequence.

How many times have you flown into a non-towered airport, trying to discern from the common traffic advisory frequency (CTAF) who else is flying nearby, and making your own sequence? You can think of that as pilot-to-pilot negotiation, and it keeps everyone safe in the traffic pattern. UTM relies on continuous information sharing and data exchange to keep UAS safely apart from each other and from manned traffic.

Because with UTM, there are no air traffic controllers like today. Instead, advanced software services, powered by dynamic algorithms, handle many of the functions that you perform as pilot-in-command today.

UTM isn’t a monolithic tool run by the FAA. It’s federated, meaning that many companies provide a suite of services that UAS operators can sign up for based on their needs. The FAA will oversee those services, provide certain types of data (like airspace information), and ensure overall airspace safety. UAS operators will rely on UTM services to help them plan routes, avoid weather, and find safe landing sites during emergencies. Services communicate with each other to safely avoid other UAS through a process called strategic deconfliction. Those services also use vast amounts of surveillance information to avoid manned traffic, making real-time course changes driven by detect-and-avoid systems.

Maybe at this point you’re wondering why such a complex system is even necessary. After all, today’s UAS pilots can safely access controlled airspace through the FAA’s Low Altitude Authorization Notification Capability (LAANC). Most of these UAS are just a few pounds, and they are intended to be flown by recreational flyers or commercial operators that fly close to where they’re standing with the controls. This is called visual line of sight, or VLOS.

Aside from making eye-catching aerial videos for real estate listings and weddings (remember those?), small UAS operating VLOS can also help first responders. Equipped with infrared sensors, fire departments use them to see through the smoke above active conflagrations, and search crews rely on them to help find lost and stranded hikers. Even small UAS have advanced autopilot functions and cameras that automatically navigate around obstacles, so it can be much easier — and less expensive — to deploy a UAS from its case in the trunk of a car, compared with calling in a helicopter.

The Future That’s Coming Soon

But UAS operators have much more ambitious plans, involving many more vehicles flying with minimal human oversight, and without a pilot and remote controller nearby. These flights are known as beyond visual line of sight, or BVLOS. That means the remote pilot or operator isn’t watching the UAS from the ground. They could be hundreds or thousands of miles away, and they may even be monitoring several flights at once from a computer screen. Package delivery flights will transport everything from books and sandwiches to medical supplies. Energy and transportation companies must inspect their infrastructure regularly, typically by driving or flying alongside electrical transmission lines, railroad tracks, and pipelines. But UAS can do those same tasks even better, using advanced image recognition to identify even a single bolt that’s out of place — details that even the best trained human driver or pilot wouldn’t be able to catch. BVLOS flights can also help with agriculture, airport inspections, construction, and other jobs by making repeated, fully automated flights to capture up-to-date imagery and other information.

A few basic UTM capabilities are already available or coming in the near future. The FAA’s DroneZone allows all operators to register their UAS, just as owners must register their manned aircraft. Building off that, most UAS will be required to transmit a digital license plate by late 2023 using a set of technologies called Remote ID. This allows members of the public, law enforcement, and public safety officials to verify whether a UAS they see flying near them is actually authorized to be in the air. This is critical to building trust in UAS operations, and it’s a building block that will enable some of the more advanced UTM capabilities that are coming.

Recent rules that streamline UAS operations over people and flights at night are building on the FAA’s experience to ensure these flights can happen routinely and safely. Through efforts like the UTM Pilot Program and the BEYOND program, companies have been testing their capabilities in low-risk settings around the United States. These programs are critical to getting everyone in the same sandbox, including operators that fly inspection or delivery vehicles, and the UTM services they rely on for flight planning and monitoring.

UTM won’t appear overnight. But parts of it exist today, and over time you’ll see a growing set of services for many different types of operations.

Learn More

UTM Pilot Program - https://www.faa.gov/uas/research_development/traffic_management/utm_pilot_program

FAA’s BEYOND Program for UAS Integration - https://www.faa.gov/uas/programs_partnerships/beyond

FAA’s UAS Data Exchange (LAANC) - https://www.faa.gov/uas/programs_partnerships/data_exchange

Peter Sachs is a UTM program manager in the FAA’s UAS Integration Office and previously worked as an air traffic controller at the San Francisco Tower (SFO) and the Chicago Executive Tower (PWK).