Further Springside recommendations
Hi Clinton,
The reason I put only one recommendation in my Review was that the problem of speech clarity by ATC is my own proposal, whereas the matter of inbound reporting points has been discussed at length by pilots. In particular, Ambidji performed a very comprehensive survey of pilots, in which the problem of conflicts at IRPs, far from the scrutiny of controllers, has been well noted.
Since you ask, I will go into more detail now. My Springside model of mid air collision (MAC) rates (described in my review) has a term depending on traffic movements alone, representing circuit area conflicts. It has a second term depending also on the restrictions at the control zone boundaries, such as the way Holsworthy and Sydney ctrl zones affect Bankstown. The theoretical basis is that such constrictions concentrate traffic which increases risk. The observational basis is that the two terms when combined (and tuned) give very good agreement with the historical MACs.
Thus there is a sound basis that removing restrictions at zone boundaries would decrease the conflicts, other things being equal. Of course all the traffic must then converge in the curcuit area, but that seems to be a lesser problem and is visible to the controller.
Thus, some suggestions could be made:
- For BK, reinstate the third Reporting Point at Westmead so that traffic from the Light Aircraft Lane does not have to divert to Prospect and combine with others.
- Make IRPs not applicable to jets on VFR, so that they can fly direct to the circuit from any direction.
- Replace IRPs with several designated lanes for piston AC on VFR, so they can join at any point.
- Lower the restricted zone at Holsworthy so traffic from S and SE can track direct.
In theory these measures would reduce the hotspots away from control. Others more experienced than I would have to work out the details.
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Last edited by Ian Bryce; 12th Sep 2009 at 05:29.
Reason: Clarification.