Judge 11 wrote:
it really is quite simple for all concerned as per the FODCOM/ATSIN
Judge 11, I have a number of "Issues" with the new phraseology - at the airport where I work, due to traffic/airspace/runway orientation aircraft regularly establish on the Localiser from 10-25nm from touchdown. The protected range of the Glidepath is only 10nm/3000ft. Due to the airspace configuration (which varies with time of day) we cannot just descend arrivals to 3000ft or lower straight away (have to descend in 3 or 4 steps) so cannot use the "when established descend on ILS" bit for these at all - we have to use the other one which requires us to say "Maintain (level)"
Repeating a previously correctly acknowledged level instruction has been identified as a major factor in Level Bust incidents - repeating opens the door to errors - and within NATS it is being drummed into ATCOs not to do it as part of the Defensive Controlling initiatives. The CAA just go and undo all the good work being done
There is also the issue that because of the need for stepped descents due to airspace, we would say "Maintain (level) and then before the aircraft established, give a further descent instruction - making the "Maintain" superfluous (extra and unnecessary RT) - but thats what the CAA have decreed.
In addition, for those aircraft that do establish within the protected range - the phraseology removes the "established" call so they potentially can be transferred to tower without a positive confirmation that the aircraft is actually established - all good up to the point where the aircraft goes sailing through the localiser.
With limited vectoring airspace that can be anything from embarrassing to dangerous if not corrected immediately.
The change in phraseology has introduced an extra possibility for mistakes (see above re:Maintain") and added to the amount of RT on already congested frequencies. Personally, I prefer the ICAO standard "Cleared ILS" (at an appropriate moment) and I believe that a simpler solution would be to make that the "Standard". At those airports where its use could cause a problem (by immediate descent to platform altitude) then the CAA should address the issue and rewrite the Instrument Approach Procedures to remove that possibility.
I predict the next move will be an increase in the protected range of UK ILS Glidepaths
DD