Near miss in the circuit. Should I have reported it?

Just because an airport has a control tower it doesn't mean you're not going to get uncomfortably close to another aircraft in the circuit, as I was to find out.

No two approaches into Moorabbin are ever same, but as I approached downwind for Runway 17R from Carrum I expected this landing to be as routine as they come at Australia's busiest airport.

Even before it was time to make my downwind call the controller said I was number two for landing behind a Cessna 172, which I quickly spotted before proudly responding with 'traffic in sight' without delay.

The 152 suddenly turned base adjacent to the runway threshold just a couple of hundred metres in front of me.

All of a sudden a Cessna 152 crossed my path from right to left about 1500m in front. It was in a climb and I thought it just took off and turned a very early crosswind, but didn't recall any radio calls to that affect.

Moorabbin is a Class D airport which means it's up to pilots and not ATC to maintain separation.

You can't do circuits on the western side of the airfield so, thinking it had taken off, when it I assumed it was departing downwind toward the city.

I started to catch up with it and kept to its right hand side as I'd be turning right on to base.

I was also a little low and started to get a good look at its belly when the controller asked if I had the 152 in sight and then asked me to maintain separation as I was now behind it for landing.

I told ATC I would extend my downwind leg to ensure separation on final. I slowed some more and started working my way to the 152's hand side when it suddenly turned base adjacent to the runway threshold just a couple of hundred metres in front of me.

Luckily I was a little low.

The controller then announced it was doing a glide approach.

For some reason I never heard the other pilot announce this or any other calls during the entire time in the circuit so was quite confused That's not to say he or she didn't make any calls, I just didn't hear or notice them.

I don't think there was ever a point that we'd have collided as there was room to take evasive action, and my memory is probably exaggerating how close we came.

But considering I had just been told to expect to be second for landing I feel that aircraft's intentions could have been better communicated to me, either by pilot/instructor or ATC, from the time it was on crosswind.

That said, I should have asked for its intentions so I could establish how best to increase separation.

I had a friend flying with me so I elected to play down any concerns I had to avoid alarming him. We ended up landing without incident and went to the Flight Deck Bar for a burger and beer and all was forgotten.

In hindsight I should have got in touch with ATC to discuss (assuming they'd remember) what I believe was an unusual entry into the circuit and if there was any communication I may have missed.

Yes, no two approaches into Moorabbin are the same, but I'm learning something from every one of them.