Dear Bob, Richard, and anyone else who may be able to help.

I am unclear about the operational requirements in Class D airspace.

As I understand it, it is not required to "request clearance" when entering Moorabbin class D airspace - it is sufficient to establish two-way communication with the tower. Also no departure call is required when departing into class G.

However, I have noticed that in order to overfly Avalon below 2500' (class D), VFR pilots are expected "request clearance".

Similarly, arriving at Albury below 4500' (class D), I was told by an instructor to "request clearance".
To further complicate things, upon departure from Albury, tower requested a "departure report" from me.

I had never read about a departure report, nor had my instructor. I scoured the AIP for information and came up with this:
- ENR 1.1 page 45, 21.1 "Summary of Reports..." which basically says a departure report is required when departing class D, unless departing straight into class G.

In my case, Albury tower prompted me for a report, even though my flight plan said I was departing for Corrowa at A025, straight from class D into class G.

Is there an explanation for these operational differences in various class D airspaces around the country? Is each a special case that must be considered in isolation, or have I missed something in the AIP (entirely possible)?

Kind regards, rubber

You're right rubber, the AIP is a bit vague in this area. I think that the main difference for the former GAAP aerodromes is that they are within the coverage of the radar controlled class C airspace adjacent to them. Although the class D airspace is not radar controlled, the class C radar does provide the guys and gals in the class D tower with another separation tool.

In the regions, class D airspace has no radar coverage at all, so the guys and gals in the tower have to rely on procedural separation, which basically means they need to know where everyone is and where they are going at all times (via VHF, clearances etc). Although VFR traffic does not receive a separation service from the tower, the tower still needs to know where you are so they can keep IFR traffic separated. The departure call gives them confirmation that you are no longer in class D airspace and they can clear you from their traffic.

My experience in regional class D airspace is that the controllers in the tower are pretty forgiving, but as a pilot you need to be pretty sharp about your exact location at all times as you are going to be asked about it pretty often, and unlike CTAFs you may be nowhere near the airfield at the time.

Thanks Ray, yes your explanation is in line with another I received from an instructor-friend by email, which I will quote here:

"Ok, so the simple answer is you do have to get clearance to enter Moorabbin's airspace.

The technical side is, Moorabbin used to be called a GAAP zone and they had specialised procedures ie; call on downwind, you must enter via a VFR waypoint. These were Australia only procedures so to remain aligned with ICAO they had to change them.

You officially don't have to say "request clearance" in Class D and the ATC only has to read back your callsign and that constitutes as a clearance. It is a clearance and MB ATC is within rights to say "remain OCTA".

All the other Class D, ie; Albury, Avalon keep doing what they always used to do as the new class D doesn't mean they can't give you traditional clearances.

I went to to Melbourne centre recently and the ATC controllers called places like Moorabbin, Archerfield and Bankstown 'Metro Class D' and the others class D."