Class D at (relatively) busy airports
 

Hi,

I'm looking for your experience on application of class D airspace in CTRs of airports serving lets say 100k-200k mvts per annum. Is traffic advisory on request really working at such airports or the controllers are issuing such advice according their own judgment and initiative?

AR

Heathrow, Gatwick, Luton, Stansted are all class D. Works very well, however controllers must apply the "common sense " principle, and not place the aircraft too close together or in a dangerous proximity to each other.

Simple coordination with the tower for aircraft crossing the airfield, or final approach or departure lane, then pass lots of traffic information to all pilots concerned.

PM me if you want more information,

Nimmer

Málaga is also Class D. Works nice except in rush hours during the summer. We do have vfr traffics (pa28 towering banners) at a very slow speed that requires to cross the QMS along the coast line (1 nm in final for RWY31). This situation is stressfull because the high load of work and communications.

But surely ATC can refuse VFR traffic if it is too busy?

I'm not sure ATC should refuse VFR traffic in Class D; the rules of Class D are very clear under ICAO and SERA, it is the responsibility of the VFR traffic to avoid the IFR. If IFR from VFR separation is required, a more appropriate airspace classification should be chosen i.e Class C or higher.

Perhaps issue an expected delay rather than refuse entry. The delay, however, might be quite long depending on the traffic levels, patterns, airspace considerations, requested routing, requested altitude, etc, etc....

Class D, IMO (humble, or not) is the most appropriate for the vast majority of control zones.
If the zone is busy/complex I don't think it's unreasonable for ATC to delay VFR transits/suggest an alternate routing to deconflict with the IFR pattern. The point of establishing controlled airspace is to protect the IFR traffic to/from that aerodrome isn't it??
Class C is more restrictive than Class D and would lead to even lengthier delays for transits and/or worse routings.
Class D offers flexibility that Class C cannot.