The more I think about this subject, the more I discover that the UK altimeter setting procedures are absolute rubbish. Some examples;
The general transition altitude is well below the highest terrain.
Looking at Brize as an example -
The Transition Altitude is 3000ft
but the top of the CTR is defined as an altitude of 3500ft.
The top of a MATZ is 3000ft above the appropriate airfield which in all cases puts it more than 3000ft AMSL thus aircraft passing over the MATS are required (for safety sake) if IFR to fly at a Flight level that keeps them above the fast moving jets that are using QFE. Does the pilot use RPS to assess separation (NO TMA, CTR or other CAS) or does he call the mill ATC unit for QNH only to be given the QFE?............The biggest danger in aviation is not knowing what is going to happen to the flight!
I am amazed that there are not more incidents relating to altimeter setting..........however I could safely say that there are several each day that go unreported or even unnoticed!!
ILS119.5..............have a look at a danger area of the big variety - all have an upper height AMSL. As far as I am aware the ACC use the RPS to separate flights crossing above i.e. use the RPS to determine a minimum FL..........however aircraft operating within the danger area could be using the QFE of an aerodrome within it!!!!!
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KPax,
Perhaps you should review the separation provided in Class D between a VFR flight (transit or otherwise) and any other flight - none. Thus QNH or QFE for a VFR transit aircraft makes little difference because all you do is give traffic info and the pilot does the manoeuvering as required to avoid traffic and maintain VMC............I have received a clearance from you guys to fly VFR at 1500ft QFE when your actual was Overcast 1000ft.....because your circuit was active............not what we would call a good idea
As for IFR - If your field elevation is 500ft and the circuit is 1000ft then you simply want the IFR flights to be not lower than 2500ft on your QNH without giving traffic info!
All very simple for someone to put into local procedures which is always safer than making it up on the fly!
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Giles,
The definition of "In the vicinity of an Aerodrome" is;
Within, entering or leaving the aerodrome traffic circuit.
In other words - the ATZ!
The limits to LARS coverage is based on radar performance, airspace issues, adjacent units, local requirements and last but not least - the CAA limit on the distance at which controllers can provide a radar service without holding an Area Radar rating.
Regards,
DFC