Changes to Scottish airspace

[Easy Street]

airwave:
There is NO requirement for you to call the ATSU before crossing a Class E airway in VFR. If you do choose to call them, you will NOT "become subject to the direction of the ATCO". They may attempt to offer deconfliction advice but this remains entirely advisory as long as you remain VFR. Of course, it would be good airmanship to comply unless there's a very good reason not to (and then it would be good airmanship to tell them). One such reason might be the need to stay VFR!

Pheasant Plucker:
The CAA are adamant that TS / DS are NOT air traffic control services, but merely flight information services. This is the convenient form of words used to explain their provision outside CAS, where FIS is the only service permissible under ICAO. Class E falls into a tricky area because it is defined as controlled airspace, even though it is effectively only controlled airspace for IFR traffic. Therefore it falls foul of the CAP493 diktat that the only radar service that can be provided in controlled airspace is Radar Control. I think it would be helpful if this could be modified to recognise the uncontrolled nature of VFR Class E operations, and allow TS/DS to be provided to VFR traffic in Class E.

There is nothing in ICAO or CAP493 that explicitly prevents controllers attempting to keep IFR traffic separated from unknown VFR contacts in Class E. It isn't required, but to anyone who says "you shouldn't be providing separation where ICAO doesn't mandate it" I point you to UK Class G in general. Perhaps the CAA might consider introducing a means by which advisory vectors can be given (for avoiding VFR traffic) whilst staying under Radar Control (for the mandated IFR-IFR separation).

What's the point of Class E, then?

1. Mandatory participation by all IFR traffic (it's voluntary in Class G, although 'strongly recommended' below 3000ft within 10nm of an IFR airfield by the UK AIP).
2. More stringent VMC requirements, most notably the increase in fixed-wing minimum vis from 1500m to 5000m. This increases the chances of unknown VFR aircraft being sighted and underpins why there is no requirement for IFR-VFR separation. Traffic info can be passed on VFR traffic as per the Class E definition.
3. ATC instructions mandatory for IFR traffic, and ATC legally responsible for IFR-IFR separation (pilot reponsible in Class G).

I will accept that some lazy IFR pilots will hear 'Radar control' and stay heads-in while in Class E. That is why the increasing application of Class E needs to be accompanied with a widespread education campaign. The key point is 2) above.... because you know that unknown traffic must be in VMC, it's pretty simple: IMC in Class E = heads-in, ATC separation; VMC in Class E = heads-out, see and be ready to avoid. Preferably with some traffic info, and possibly advisory vectors.

The 5nm / 3000ft separation sought under DS reflects the fact that one or both of the contacts could be IMC. Essentially, it seeks to apply ICAO Class B separation rules (all traffic from all other traffic) on a "best effort" basis in a Class G uncontrolled traffic environment. It's no wonder that the GA community is becoming a bit wary of ATSOCAS when they're described that way. At least with Class E rules you know that unknown traffic must be VMC, and therefore has half a chance of being avoided visually. If some form of advisory service could be introduced for Class E VFR traffic, there could be a case for the radar separation minimum to be reduced to (say) 3nm or even 1nm in recognition of this fact, which would encourage GA participation by reducing the extent of vectoring.