Firstly, understand there are two types of pilots:
I expect that for the next 2 months, I will be approached by people out of the 1st group who will explain it all to me, they will show me hundreds of different paragraphs and diagrams in Air Pilot, on charts, etc etc, and I will say 'Oh I see, thank you for sharing that with me' but I will guarantee it will be slightly different view from the previous expert or the next one. Most of the differences will be based around what a given paragraph doesn't say you can't do, if you see what I mean. If you ever get two of these people together, they never end up agreeing, they finally wear each other down with phrases like:
'Ah, you are confusing VFR with VMC', or 'You are confusing the licence privileges with VFR', or 'Yes, that paragraph might not allow it (whatever it is they are arguing about) but this one over here doesn't say anything about not doing it in Class D Airspace not subject to Minimum Weather provisions'. (How many 'nots' can you get into a sentence).Now, on the assumption that confusion and safety don't really go together, I've opened up the can of worms, and I'm sure I'll regret it, but let's just look at one topic: VFR and SVFR around Southampton or Bournemouth which is "Class D Airspace not notified for Minimum Weather Provisions". (Get the idea already that complications are afoot? - well in 1996, it just becomes plain "Class D Airspace", so we'll run with that.)
At the time of writing it is up to the pilot to decide on visibility not the met man at the airfield so arguably the met man could say that visibility was one thing, but the pilot could decide it was far better than that. However, this point is soon to change, so let's assume that it has, and the declared visibility is legally enforceable.
What do we mean by VFR? Well, basically and simplistically, you the pilot are responsible for looking out and providing your own separation from other traffic, which is why controllers are quite happy to VFR-clear both inward and outbound traffic over the same VRP (Visual Reporting Point) even if they could use different ones. Again, changes are in the pipeline to rename "VRP" to "VRP"! No difference? Well, they become Visual REFERENCE Points, in the hope that some controllers might actually not steer all traffic head on at each other over the same spot, but clear them with reference to a point (eg: outgoing traffic cleared West of Calshot, incoming East of Calshot). Sounds too sensible to be used properly.
Right, Where were we? Ah yes, VFR Clearances in Class 'D' Airspace. If the visibility is less than 5000 metres, NO VFR clearances. If you have a straight PPL, and it's less than 5000 metres vis, then you can't legally fly into (or out of) Southampton. You should go and land somewhere else like Old Sarum, Thruxton, etc, or wait!
Now Special VFR. This means that the controller now has some responsibility for separating you from other SVFR or IFR traffic, but note, not VFR traffic, who have taken the responsibility themselves. There are two visibility limits to remember with SVFR - normally it is 10 Kilometres (YES, more than VFR!). If you have an IMC rating then it is only 3 kilometres. You know what you've got, not me. The other day I was approaching a VRP behind a Cessna in 7000 metres visibility with no other traffic about. They got there first and asked for SVFR entry for some reason - I don't know why (perhaps they didn't either). However, had I then asked for SVFR, I would have been held by the controller until he or she could guarantee separation between us (probably by letting the other one land first). The controller was good enough to hint to me what was going to happen by asking what clearance I require but adding that the one ahead was SVFR. I could quite clearly see the one ahead, so I went in VFR, and there was no delay, as I had not put any responsibility on the controller to separate us.
I think what confuses people is that once the viz gets below 10 kilometres, the controller seems more likely to put a worried note into the 'What sort of clearance do you require?' question, and PPLs seem to notice this and think:
"Well, this haze is dodgy, I can't remember what SVFR is, but it sounds like I might need it, so I'll ask for Special VFR".
Firstly, they then wonder why they are orbiting a VRP for twice as long as usual. (Answer, the controller won't let you in until he/she is sure there is formal separation from other SVFR or IFR). Secondly, as a normal PPL you cannot legally have a SVFR clearance at Southampton under 10 kilometres, so if you asked to go SVFR because of haze giving a lower visibility, then you'll get one (the Controller will assume you have an IMC rating) but your clearance will be illegal!
However, if it is legally possible and you want a SVFR clearance and you know why you want it, then have one, but I get the impression some pilots ask for it expecting it to suddenly make the visibility better for them personally on hazy days!
If you want an example of when I've asked for SVFR, there was one day about 6 weeks ago with good visibility, but there was a strange band of very low cloud about 3 miles to the South of the airfield, which itself had good weather. Coming in from the South, controlled airspace starts about 8 miles out, and half of the transit is over built-up areas. The SVFR absolved me from the 1500' above towns, so I could duck low under the cloud without any legal comebacks (unless I was within 500' of anyone or anything). My request for SVFR did hold up one southbound departure briefly but once past the cloud, I was able to climb and swap the SVFR for an VFR, allowing another aircraft to depart.
Pilots with IMC ratings can take SVFR clearances down to 3000 metres. On the recent Middle Wallop day Bob E. spotted we had two aircraft there returning to Southampton at the same time, and the viz was 5000 metres. He intervened with the seating arrangements to make sure the two IMC rated pilots split between the aircraft just in case the visibility got down below 5000 metres and normal PPLs were legally excluded from either VFR or SVFR to Southampton. Good thinking and understanding of the rules.
One story from the hazy week: I heard someone in a twin-engine aircraft orbit for ages at a VRP because they had requested a SVFR with visibility at 7000 metres. Let's assume they had an IMC rating so the story remains legal. There was no cloud, just haze. Surely an IMC pilot didn't really need a SVFR when the only other traffic was me (VFR) on a direct approach from Guernsey and an expected IFR? The controller on tower had to guarantee separation between the IFR and SVFR, so the twin was left orbiting at the VRP for ages whilst he checked the position of the IFR with the radar room and whilst I did a long straight in VFR approach well ahead of both. On short finals myself, I heard the twin threaten to declare a "full fuel emergency" if not allowed in soon (probably deciphers as 'getting bored', and didn't make that much of an impression on anyone - perhaps an "empty fuel emergency" would have impressed more people.)
The twin would have landed and parked long before I was on finals if it had requested VFR, but I'm sure it was a case of 'not sure what it all means' rather than wanting a SVFR. Getting to a VRP with (if you believe it) not much fuel sounds pretty stupid anyway, so who knows what was in the pilot's mind.
In saying that, I'm not blaming pilots really, even though they are supposed to know, but I point to our favourite QUANGO, who seem to delight in making everything so complicated that there is just too much to know. It reminds me of a programmer I knew who made his programs so complicated people couldn't use them without asking him how to do it, and that 'proved his superiority' (in his tiny mind). 1996 will bring some relief, in that the two types of Class 'D' airspace will disappear, and the one left will have the rules we currently know at Southampton, except that "Met Observations RULE - OK?" for aircraft arriving or departing there. You can make your own mind up about the visibility if you are in transit.
Got an IMC rating? Yes, you can accept IFR transits, departures and arrivals at Southampton. I wouldn't do it without recent practice though, and the 'plates' on board.
The more confused the pilot, the less safe the situation. I hope I've managed to clear up a little corner of it all relevant to some of us without introducing any big mistakes. I'm sure I'll hear about it if I have - but remember, you can't go by anything I've written, as no-one understands this subject...