Talkdownman;
If we talking purely ICAO here then DOC 4444 8.9.7.1 describes the SRA procedure. It also goes on to cover the PRA.
DOC 9432 7.6 outlines the associated SRA phraseologies and a couple of rules.
Regarding your following statement:
"If the pilot chooses not to fly the GP then he will need to inform the controller who may be tilting the SRE aerial elsewhere and may easily lose the target".
Not to confuse the SRA with the PRA, this is only the case in a PRA when the aerials are moved by the controller via a servo. In the case of an SRA the surveillance radar is used and a line created from the start point of the approach to the touchdown markers (where available) - normally using a dynamic map - which replaced the old chinagraph overlays).
Heathrow Director:
As posted albeit probably ar*s about face, the VFR in emergency rule is as per the Ozzy MATS. I cannot find such a "rule" laid down in any ICAO docs.
FORUM:
Points to consider ( maybe). When completing an SRA you are vectoring and passing advisory altitudes. As the SRA obviously goes below minimum safetly/ vectoring altitudes etc caution needs to be exercised as to how far left or right of centreline you start the descent ( clearances planes and all that )Whilst a PRA may be calibrated the SRA is not ( I think). Once you start vectoring below MSA/MVA you take responsibility for terrain clearance (unless the pilot is flying VFR in VMC then its obviously only a training approach in which case you would remind him of his terrain clearance responsibilities).
Therefore, and from an operational approach aid viewpoint, it seems reasonable that this procedure is intended only for pilots unable to carry out a visual approach i.e. IFR. By default, to accept the procedure pilots must be able to fly on instruements i.e. IFR qualified - or - the weather has deteriorated below VMC minimas and a pilot needs to land; thereby breaking the VFR flight rules. This could be classified as an Emergency situation perhaps.
Obviously the approach can be carried out by VFR pilots when the weather conditions allow flight in VMC; for both controller and pilot training etc. After all, with UK weather ( unlike Brisbanes for example), one never knows when the weather is going to necessitaTe a change in the best laid plans.
Im not familiar with UK MATS but can only speak form experiences doing many SRAs whilst in blue and of my current knowledge and practice "Down Under" using local docs and ICAO refs. So apologies if I am a bit wide of the mark where your particular books are concerned.
DogGone
