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Helicopter collision avoidance: Moving your eyes and your head

By Simon Sparkes | February 6, 2024

Estimated reading time 9 minutes, 40 seconds.

The first thing I probably learned during pilot training was how to do a good lookout. It was the building block for my initial military fixed-wing flying, and I was never quite sure whether it was about avoiding other aircraft or finding them so that I could shoot them down.

In order to exercise the right level of vigilance, the pilot should fly any maneuver required to avoid other airborne users, and this is generally referred to as the see-and-avoid principle. Lloyd Horgan Photo

What I have definitely understood since then is that a good lookout can be a lifesaver, but it is not a complete solution because sometimes, your eyes either do not or cannot see the other airspace users around you.

Recent examples, such as the Gold Coast Sea World helicopter mid-air collision in January 2023 or the Haneda Airport collision in Tokyo, Japan, in January 2024, show that mid-air collisions have not gone away despite the introduction of new technologies or air traffic control (ATC) interactions.

ICAO Annex 2 lays down the Rules of the Air for all of us, containing the requirement that “an aircraft shall not be operated in such proximity to other aircraft as to create a collision hazard.” It also states that “it is important that vigilance for the purpose of detecting potential collisions be exercised on board an aircraft, regardless of the type of flight or the class of airspace in which the aircraft is operating.”

To break this down into more friendly language, in order to exercise the right level of vigilance, the pilot should fly any maneuver required to avoid other airborne users, and this is generally referred to as the see-and-avoid principle.

When I started in aviation in the 1980s, there were really only two ways to deliver good collision avoidance techniques — one was by using my head and eyes to scan the airspace around me, and the other was to get support from ATC which would seek to see my aircraft either through the use of raw radar returns or a transponder. 

What I quickly discovered, as most pilots eventually do, is that using your head and eyes is subject to quite a lot of errors, not least of which is a complete inability to look in all directions at the same time. In addition, there are some well-known physiological issues with human eyes. Something on a collision course, not changing in bearing or speed, is notoriously difficult to see even when the other aircraft is painted bright yellow or red and white (as trainer aircraft were in those days). Moreover, research then showed that such colors were a complete waste of time and that, actually, black painted aircraft tended to be much easier to see against a blue, white or grey sky (as it typically is).

In the absence of better technical solutions, pilots can get more assistance by asking for help from ATC, but of course, ATC is often not interested if you are flying VFR (visual flight rules) and a lot of times, there really isn’t enough radar or transponder coverage at helicopter operating altitudes to give a meaningful or complete picture. 

Such support, if it is available, is nominally very 2D in nature with simple range and bearing calls from the controller, with you, as the interpreter, to guess what height other traffic might be at — unless of course they have a transponder that tells the ATC unit their height. But this is all still a little late when aircraft are getting close to each other, especially when coming from above or below.

Of course, this scenario is assuming there’s great VFR weather with 10-kilometer (six-mile) visibility and 1,000 feet (300 meters) from cloud to support good visual identification. But what happens when we get into “real” helicopter weather, with maybe as little as five (or perhaps three) kilometer visibility? We have probably all seen traffic “pop out” of the murk and into our eyelines, or worse, flight path before we make an attempt to avoid.

For years, in my case, this was it. I flew around various countries and areas sometimes seeing other traffic without prompting, sometimes not seeing the traffic that I was told about, but luckily, only on a few occasions actually having to avoid an aircraft and possibly a collision. Often the aircraft I wouldn’t see were gliders or light aircraft, colored white and notoriously difficult to identify against a cloudy background or even bright blue summer sky.

As technology has advanced, more technical aids to collision avoidance have emerged, based on the original principles of transponder technology but increasingly benefiting from the introduction of GPS and integration of “carry-on” equipment, such as electronic flight bags and miniature transponder devices (the system called FLARM came from the glider community). 

At the higher end of both fixed- and rotary-wing equipment are traffic alert and collision avoidance systems (TCAS), firmly built on the original transponder systems and giving the best 3D coverage and avoidance guidance, if you can afford it. ADS-B systems, unlike TCAS, really only enhance situational awareness by broadcasting an aircraft’s position to other aircraft and ground stations, and require a level of interpretation to use correctly.

With all of these systems now in play, I still find myself surprised at the amount of traffic that I see visually that doesn’t actually appear on a TCAS or ADS-B display. This is especially true across Europe where the fitment of transponders or other conspicuity systems is not mandatory for all airspace users and these continue to grow exponentially now that drone systems are proliferating. It really is not the time to stop looking out or to use ATC when you can, to give you a better idea of what might be around you and what they might be doing. Good route planning can help here as you can checking NOTAMs (notice of air mission) in order to trigger an idea where lookout needs to be heightened or perhaps ATC help asked for.

The evolution of electronic information systems to improve aviation collision avoidance has seen steady progress, serving to enhance safety and mitigating the risks associated with flight operations in all types of weather and airspace. But this has not replaced the need for the pilot to look out the window. It is easy to be seduced by displays and other electronic tools when you’re flying, especially in aircraft with good auto flight control systems. Just because the screens are clear. it doesn’t mean the skies are and it is a matter of survival that we move our eyes and heads regularly even when everything seems quiet.

It is easy to be lulled into a false sense of security but all pilots have a duty to see and avoid at all times when operating an aircraft, on the ground and in the air.

Simon Sparkes is a test pilot for the Norwegian Defense Materiel Agency who started his flying career with the Royal Navy at the end of the 1980s. With over 50 aircraft types in his logbook, his experience has ranged from anti-submarine warfare operations on the Sea King, to basic helicopter instruction on the Gazelle, to commercial light twin operations in both the EC135 and AS355. Previously the commanding officer of the Empire Test Pilots’ School, he currently works on a variety of projects with the AW101 SAR Queen in the challenging Norwegian environment.

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