Tag Archives: safety

Close encounters in the circuit: Was the other guy in the wrong, and what can I learn?

It’s been nearly two weeks since I last flew, and in that time I’ve returned to full time work. The balance of my PPL – perhaps another 15 hours – will now have to be done on a part-time basis, maybe once a week. Factoring weather variability in, I anticipate it will take another 2 to 3 months.

Back in late April I made my maiden cross-country solo flight, a 2-hour return trip down the Hume Highway nearly to Marulan, then east direct to Wollongong, land, then direct north back to Bankstown. It was a fantastic trip on which I learned a lot.

But there’s one thing that stands out particularly, and the more I think about it, the more it’s got me reflecting on the question of safety in the circuit.

Standard circuit legs

To set the scene, for any non-flying readers, there are standard “legs” that you fly when flying in the circuit around a landing strip. As described in the diagram below, these legs are always relative to the “active” runway in use. This in turn depends on the prevailing weather conditions, in particular the direction from which the wind is blowing.

For illustrative purposes: in the below diagram, the runway runs in the 11 (110 degrees magnetic) direction (from top to bottom of page) and in the 29 (290 degrees magnetic) direction (from bottom to top of page). Let’s assume the wind is currently blowing from 110 degrees magnetic. In this situation, the runway in use would be runway 11 – that is, takeoffs and landings take place in the 11 direction, “into the wind”. The standard circuit legs are sketched accordingly, assuming a standard left-hand circuit.

The situation at YWOL

When I landed at Wollongong (YWOL) back in April, this was the standard circuit in operation that day. (YWOL’s north/south runway has different headings to the example I’ve sketched in the diagram, but the principles and circuit legs are the same).

I approached YWOL from the west and made the standard 10-mile inbound call on the YWOL CTAF (Common Traffic Advisory Frequency). I then descended to circuit height by doing a couple of orbits on the “dead” side of the YWOL circuit (on the left hand side of the runway with reference to the above diagram).

At circuit height, I made the mandatory CTAF call indicating my intentions and joined the circuit “mid-crosswind”. That is to say, I flew at circuit height across the runway, from left to right as you view this diagram, more or less right across the middle of the runway between the north and south ends.

Once across the runway and on the “live” side (on the right hand side of the runway with reference to the above diagram), I then turned onto the downwind leg of the circuit, making the mandatory CTAF call as I was doing so.

Now, here’s where things got interesting. The following amended diagram hopefully illustrates the situation.

As I flew downwind, and (as I recall it) not long before I was due to make my base turn, I heard a call over the CTAF, “Traffic Wollongong, Diamond XXX [I don’t remember his call-sign] joining base for 11”. (Actually it was for runway 16, but I’m trying to stay consistent with my diagram). I glanced ahead of me and to my right, and a second or two later, there he was, joining the base leg from my right – and it was the first time I’d seen him! I was not a little surprised. Here I’d been happily tooling along, alone in the YWOL circuit, and all of a sudden I had traffic joining the circuit ahead of me and flying directly across my flight path from right to left.

(The diagram may be a bit misleading insofar as the scale is off. The Diamond was not as close to me as the diagram suggests. But having said that, I felt the separation between our two aircraft was more than a tad too close for comfort).

A split second’s assessment and I decided on two things:

  1. That I was not at risk of colliding with the Diamond – he flew right across my flight path from right to left, and was quickly clear of my flight path. I did not need to take any sort of evasive action. Having said that, if he was any slower, or if he’d been much closer to me when he joined base, I do feel that I would have had to take evasive action.
  2. To maintain adequate separation between the Diamond and me, I would have to fly an extended downwind leg and then turn base later than I usually would, in order to give the Diamond time to land and clear the runway before I came down behind him. (I would have course had the option to go around had I approached the runway and felt that landing was still not safe, but this did not eventuate).

So that was that. The Diamond landed. I flew a slightly longer downwind leg, then turned base and final and landed uneventfully.

My take-outs

The more I’ve thought about this since, the more I think it’s one of those classic learning situations in aviation in which, regardless of who’s “in the right” and who’s “in the wrong”, the critical importance of maintaining situational awareness and practising alerted see-and-avoid techniques is highlighted.

Was I in the wrong, or was the Diamond?

It’s difficult to say. I definitely felt that the Diamond’s entrance to the circuit was too sudden, that he did not give enough notice of his intentions, that he was too close to me, and that he was unaware of my presence in the circuit.

Checking the current AIP (Aeronautical Information Publication), I note that para 47.7.1 in AIP ENR 1.1 notes the following (the italics are mine):

Joining on Base

Joining in base leg, whilst not prohibited, is not a recommended standard procedure. CASA recommends pilots join the circuit on either the crosswind or downwind leg. However, pilots who choose to join on base leg should only do so if they:

  1. have determined the wind direction and speed;
  2. have determined the runway in use;
  3. give way to other circuit traffic and ensure the aircraft can safely (no traffic conflict likely) join the base leg applicable to the circuit direction in use at the standard height; and
  4. broadcast their intentions.

I am aware, from some introductory Googling, that there is a wide variety of opinion around the practice of joining circuits on the base leg (and even more so around joining on final). Some are for it, some against it. And CASA does not make things easier by not recommending, but then failing to forbid, joining on base. Based on the above, it must be acknowledged that the Diamond was not breaking any rules simply by virtue of joining the circuit on base. However, I certainly believe that the Diamond contravened provision (c) in that he did not give way to me, and in that he did not ensure adequate separation between his aircraft and mine. I also feel that he contravened provision (d) insofar at it was literally only a second or two between his radio call for joining base and his proceeding to do so.

On balance, I’ve arrived at the view that – strictly speaking – the Diamond was in the wrong.

So what? What about my situational awareness?

With all that said, I have to acknowledge the fact that I was completely unaware of the Diamond’s presence until his base call and joining base. I did not see him until alerted to his presence by his radio call. And I can’t say for sure whether he did, or didn’t, make his inbound call at 10 miles or closer. If he had made an inbound call, you could certainly make the case that good airmanship on my part – had I been listening out carefully on the YWOL CTAF – would at least have put the Diamond somewhere in my “mental picture” of the YWOL traffic situation and made me at least aware that he was out there somewhere and inbound. Had this been the case, I could perhaps have been more vigilant when joining and in the circuit, perhaps been slightly more ready to respond to his arrival, and perhaps have seen him earlier through more active scanning.

What did I learn?

  1. Be super-vigilant in the circuit, especially at non-towered aerodromes. Just because you haven’t heard radio calls from other aircraft doesn’t mean they aren’t out there – somewhere – perhaps quite close to you.
  2. Don’t assume you’re alone. Even if you can’t see any other traffic – if you’re not hearing any – expect the unexpected. Keep scanning during all legs of the circuit, including directions from which you may not normally expect traffic to appear.
  3. It doesn’t matter who’s “right” and who’s “wrong” – you’ve still got to stay safe. This was not a particularly close call, but it could have been, and in the heat of the moment, no-one cares who was the good guy and who was the baddie. It’s still my responsibility to remain alert and to see-and-avoid, to keep myself and my aircraft safe, even if the other guy’s not doing the right thing.
  4. I did the right thing and handled the situation well. I heard the Diamond’s call; I immediately spotted him; and I took positive steps to avoid him and to ensure adequate traffic separation.

As a result of this experience, hopefully I am now a safer pilot. But I’d be really curious to hear the views of any other pilots reading this.