Who Gives Way? Right of Way and Collision Avoidance

Why it matters

Two aircraft on a converging course close at the sum of their speeds. Two trainers at 100 knots each have less than a minute from being a dot on the horizon to sharing the same piece of sky. There is no time to negotiate, so the rules of the air decide in advance who moves and which way. If both pilots know the same rules and both react the same way, the geometry sorts itself out. If one of them hesitates or turns the wrong way, the rules are worthless.

CAR 602.19 sets those rules, CAR 602.20 adapts them to aircraft on the water, and CAR 602.21 states the principle that sits above all of them.

The principle above all the rules

Before any right-of-way rule, CAR 602.19 makes two things clear. Having the right of way never excuses you from avoiding a collision: if there is any risk, the pilot with priority must still act. And an aircraft known to be in an emergency gets the right of way from everyone else. Separately, CAR 602.21 prohibits operating so close to another aircraft that you create a risk of collision at all.

Read that way, "right of way" is not a licence to hold your course. It is a rule about who moves first and which way, so that the two of you do not turn into each other.

Converging: the aircraft on the right has priority

When two aircraft converge at roughly the same altitude, the one that has the other on its right must give way. Think of a car at a four-way stop: yield to the vehicle on your right. If a Cessna appears in your right windscreen on a converging course, you give way; if it appears on your left, you have the right of way (and you still watch it like a hawk).

The exceptions are a pecking order based on how easily each type can manoeuvre. A less manoeuvrable aircraft gets priority over a more manoeuvrable one:

1. Balloons have priority over everyone;
2. Gliders give way only to balloons;
3. Airships give way to gliders and balloons;
4. Power-driven heavier-than-air aircraft — that is you — give way to airships, gliders and balloons.

In addition, any power-driven aircraft must give way to an aircraft that is seen to be towing a glider or other object, or carrying a slung load. Between two balloons at different altitudes, the higher balloon gives way to the lower one.

When you are the one giving way, you may not pass over, under or ahead of the other aircraft unless you do so far enough away that no risk of collision exists. The safe, expected move is to turn away — usually to the right and behind the other aircraft.

Head-on: both turn right

When two aircraft approach head-on, or nearly so, and there is a risk of collision, each pilot alters heading to the right. Neither has priority; the rule works only because both do the same thing. Climbing or descending is not the prescribed response — it can put you exactly where the other pilot is going.

Overtaking: the slower aircraft has the right of way

An aircraft being overtaken has the right of way. The overtaking pilot — whether climbing, descending or in level flight — must give way by altering heading to the right, and stays responsible for keeping clear until the overtaken aircraft has been entirely passed and is clear. A later change in the relative positions of the two aircraft does not hand the obligation back to the slower pilot.

Near the aerodrome: landing aircraft first

Around the runway the rules favour the aircraft that is committed to landing:

• An aircraft in flight or manoeuvring on the surface must give way to an aircraft that is landing or about to land.
• When two aircraft are approaching an aerodrome to land, the one at the lower altitude has the right of way.
• That lower aircraft may not use its priority to overtake or cut in front of an aircraft at a higher altitude that is in the final stages of its approach.
• Nobody may begin a take-off or landing until there is no apparent risk of collision with any aircraft, person, vessel, vehicle or structure in the take-off or landing path.

On the water: behave like a boat

A seaplane taxiing on a lake is still an aircraft, but CAR 602.20 borrows the marine logic. If another aircraft or a vessel is on your right, you give way. Meeting head-on, you alter heading to the right. Overtaking another aircraft or a vessel, you alter heading to keep well clear of it. Notice that boats count: the sailboat on your right has the right of way over your floatplane.