Mid air collision avoidance system (DC crash)
 

I was recently reflecting on the tragic mid-air collision that occurred in Washington, D.C., and a thought came to mind that I believe could potentially help avoid such accidents in the future. While I’m not an expert in aviation systems, I thought it might be worth discussing this idea to see if it holds any merit.

The central issue I see with the current Traffic Collision Avoidance System (TCAS) in high-density airspaces—like near major airports—is the frequent warnings that can overwhelm pilots. In some cases, this can lead to pilots disabling the system, which could be dangerous in the event of an emergency. Given this, I was wondering if it would be feasible to develop a system that:

1. Takes Data from ATC and ADS-B: A system that integrates real-time data from both Air Traffic Control and Automatic Dependent Surveillance-Broadcast (ADS-B) systems to track all aircraft in the vicinity, both in the air and on the ground. This would allow for better situational awareness and reduce the likelihood of missed warnings.
   
2. Dynamic Collision Radius: Unlike TCAS, which has a fixed collision radius, the proposed system would dynamically adjust the warning area based on air traffic density. In high-traffic zones, the system would reduce the radius to prevent excessive warnings, while in less congested areas, the radius could expand to cover more space. This would allow for better management of alerts, reducing the chance of pilot desensitization.
   
3. Predictive Trajectory Modeling: The system could use real-time data to predict aircraft trajectories, calculating the likelihood of a collision based on their future positions. If two or more aircraft are projected to come dangerously close to each other, the system would provide a warning well in advance, allowing pilots to take corrective action.
   
4. Graded Alerts: A graduated warning system could be implemented, where early-stage alerts (e.g., yellow) are issued when a potential conflict is identified, followed by more urgent warnings (e.g., red) if the situation escalates. This would give pilots time to react while avoiding panic or confusion caused by false alarms.
   
5. Automatic Integration with ATC: The system could also communicate with Air Traffic Control (ATC) to suggest course corrections or provide real-time updates on potential conflicts. This would ensure a collaborative approach between the pilots and ground controllers, further reducing the chance of accidents.
   

While I am aware of the existing systems in place, such as TCAS, I believe that this approach—by predicting potential conflicts earlier, adjusting to traffic density, and utilizing integrated data from both aircraft and ATC—could be a useful enhancement to existing technologies.

I’m by no means an expert on these systems, and this is just a thought based on my reflections about this incident. I’d be really interested to hear from others who have more experience in aviation or collision avoidance systems to see if this idea is technically feasible or if there are any considerations I may not be aware of.

Thank you for taking the time to read my idea. I look forward to hearing your thoughts!

From a safety point of view the suggestion considers the symptoms of the accident opposed to addressing the underlying 'cause', which at this time appears to be the mixing IFR and VFR traffic, and reliance on visual separation at night.

Technically, the suggestion might be better assessed in a technical or ATC forum, but beware adding further complexity in an already complex operational system, where even small changes could have an unexpected outcome.

Moved from Safety etc forum as suggested.

I think #3 is going to be the sticking point. Pretty much by definition, visual separation means you're able to get quite close to other traffic and avoid them at the last moment (say, on a direct collision path until five seconds out), and this is 'acceptable'. So you can't give any kind of serious alarm ten/twenty/thirty seconds out, because 99% of the time it'll be 'totally under control' and an annoying false alarm.

To be effective, any collision warning/avoidance system needs to give you enough notice to be able to avoid traffic, meaning it has to activate before your last chance to safely avoid them. To not give a huge number of false alarms, it has to activate after you would have needed to act to normally avoid them.

Visual simply doesn't give a gap between those those two times, so a collision avoidance system is not really practical. Enhancing awareness is all it can do.

Anyone who's sat with a learner driver through roundabouts/gap selection has doubtless experienced the trouble you have doing this.

There are a lot of these kind of systems out there already - you could cram your cockpit full of them but in an ATC/CAS environment, having separation standards that are enforced is IMO an easier solution. IFR vs. VFR at night (or poor vis) inside the circuit pattern of a major airport just shouldn’t be planned. There are limits to the safe capacity of various forms of airspace depending on their use and commercial pressure should not modify these.

There is also the issue of deviation from your assigned path through the sky because of a perception of risk actually making the situation worse by going against the plan. TCAS is integrated into ATC/pilot operations and formally trained/qualified at both ends otherwise it wouldn’t work.

Civil aviation isn’t quite ready for the whole autonomous agent thing, driven electronically but it’s probably where we will end up. After all, it’s how it started: no real rules, just pilots seeing and avoiding each other (mostly...).