Question for LHR ATCOs

[M.Mouse]

I am sure there is a good reason but why when R/T is generally very busy at LHR are we cleared to intercept the localiser and after reporting established cleared to descend with the glideslope?. .. .Is it not possible to give us a closing heading and clear us for the approach/ILS?. .. .Ta very muchly.

[HEATHROW DIRECTOR]

Hi Mickey. This is an old chestnut which regularly comes up on PPrune. The reason why we do not clear you for an ILS is because, in the past, pilots having been so cleared have descended to a ridiculously low height - 1200 ft over central London I recall! There is a lot going on under our ILS approaches - helicopters, LCY traffic, police a/c, etc so it's essential that we protect them. Separation from such traffic is based on the assumption that when we say "descend on the ILS" you'll follow the glidepath. I accept that even this is open to misinterpretation.. but I don't make the rules.

[Scott Voigt]

Heathrow Director;. .. .Any reason you can't just give them an altitude to maintain until either established on the LOC or until the marker???? Something along the lines of " BAW123, four miles north of lima, turn right heading 250, cross Lima at 2000, cleared ILS runway 27L????. .. .regards

[HEATHROW DIRECTOR]

Hi Scott. Another problem we have is lack of RT time. Your phrase (assuming I include the word "altitude", which is mandatory) takes up about 36 syllables. Our standard R/T to produce the same effect would take about 29. I know it sounds daft but if we dished out long phrases like you suggest we would lose our tight spacing ability (2.5nm in the right conditions). . .. .All the best..

[NigelOnDraft]

Lhr Dctr.... .. .Problem is we often end up on Lczr, and then can't get a word in. In practice we normally do just descend on the GP and let u know when we can.. .. .With a 757/340, once you get much above it, getting back down can be nigh on impossible.... .. .NoD

[Duke of Burgundy]

At Heathrow we are forbidden from using the phrase "cleared for the ILS runway XXX". This is for the very good reasons explained by HD. The actual problem which has occurred in the past when aircraft have been cleared for an ILS approach is that some pilots have taken this to be a clearance to descend to the altitude at which the ILS/DME approach commences according to the approach plate i.e. 2500ft, irrespective of their previously cleared altitude.. .. .A phrase which is permissible and which I use frequently, particularly when an aircraft is on a closing heading to join the localiser at less than 10 miles where continuing descent is perhaps more critical than further out is, "C/S descend to altitude 2500ft, when established on the localiser descend on the ILS". It sounds a bit of a mouthful but it does the job. <img border="0" title="" alt="[Wink]" src="wink.gif" /> <img border="0" title="" alt="[Wink]" src="wink.gif" />

[Scott Voigt]

HD;. .. .I understand about being busy, but you have to admit, we have our share of busy here &lt;G&gt;... It is our standard phraseology here.... .. .regards

[NigelOnDraft]

DoB. .. . "C/S descend to altitude 2500ft, when established on the localiser descend on the ILS". It sounds a bit of a mouthful but it does the job . .. .It might be a mouthful, but it is one instruction. Splitting into 2, as HD advocated, is far more of a problem if we can't get a word in to get the second half of the instruction.... .. .Other airfields often say "Clear ILS xx, not below yyyy' until on the Glidepath" which seems even shorter.... .. .NoD