Circuit separation

[fireflybob]

Well it's been quite a busy day in the circuit with all the pent up demand after the Christmas break and poor wx in December.

We end up with the vast majority of the a/c in the circuit on base leg or final because many folks decide to "extend downwind" for separation instead of using the upwind end of the circuit to achieve this aim.

Why can't we teach more pilots to go around from the normal base leg at circuit height so that the guy behind can fly a normal circuit?

The circuits just seem to get bigger and bigger!?

[152captain]

RE: Extending the upwind

I was fulfilling the night requirements for the Canadian PPL night rating one fine night at CYHU in Montreal. It's a fairly busy training environment, full ATC tower, 3 runways. That evening there were 9 aircraft in the circuit, 3 on one runway, and 6, including myself on the parallel. We were doing right hand circuits, with a cct alt of 1000 ft, and a cross wind turn at 500 ft. As the night progressed, the aircraft were bunching up infront of the aircraft in front of me.

So, the gentleman ahead of me decided to slightly extend his upwind leg. After a couple of circuits I found that I had to extend my own upwind leg just to keep separation, and was turning crosswind at about 900 ft. The upwind extension was so excessive that I queried the tower whether the a/c in front was remaining in the circuit. The tower confirmed, and we continued our tour of the surroundings. On the next circuit you can guess what happenned...the a/c behind me turned a normal crosswind (500 ft) and cut me off badly on the downwind (he thought we were both leaving the cct). Pretty scary at night, the a/c was maybe 200 ft above and ahead of me on the downwind. All of this at a towered field that normally provides excellent ATC, and is vastly familiar with the behaviour of students in the cct.

Incidentally, the optical illusion I incurred was quite severe, I still believe the delinquent a/c appeared to be flying backwards toward me on downwind.

I realise the problem was probably caused by radio inattention of the delinquent a/c, crowded cct, and slightly complacent ATC, but the excessive extension of the upwind legs started it all IMHO.


152

[fireflybob]

Yes but we can all quote cases of this and that happening, 152 captain and I think the environment which you are operating in is quite different to the situation in the UK.

Normal airmanship needs to be applied to extending upwind - perhaps a call to ATC "extending upwind" would keep everyone in the picture?

There is just as much hazard (probably more) associated with having all the a/c in base leg/final.

The point I am making is that we (in the UK) generally are not teaching students how to separate in the circuit environment.

[Blue Hauler]

fireflybob

Surprising the number of pilots, including instructors, who do not recognise the benefit of extending upwind to make the circuit fit a large number of aircraft. It is so much easier than extending down-wind, particularly when attempting to set up base from a constant position with early students.

Frustrating, isn't it?

[I Fly]

Our control zone has a 4 nm diameter and 1 runway. We have had up to 9 aircraft in the circuit. Depending on your performance there are 7 - 8 trackmiles in a circuit. With a bit of speedcontrol there should be no problem maintaining 600m + separation without extending anything. If you have to extend, it depends on the surrounding airspace as to where you can.

[Tinstaafl]

I always taught speed control first then look at modifying the circuit, preferably by extending upwind then downwind and occasionally by flying wider than normal. Sometimes an orbit can help. Even overtaking is sometimes more appropriate.

The main thing is to think & anticipate! Not just how to separate from the a/c ahead but also how your actions or inactions will affect following a/c and also forthcoming circuits.