LVP, ILS protected ranges..

[dimmolto]

Does anyone know the answer to these questions:

What additional calls do you have to make during LVP's?

What is the ILS protected ranges?

[HEATHROW DIRECTOR]

As I recall, no mandatory calls are made by pilots or ATC during LVPs except by ATC to state that LVPs are in progress, which probably goes out on the ATIS. At airports where there is no ground radar pilots may be asked to report when they are clear of the runway. In the approach phase ATC may ask aircraft for their minima but this is purely for information.

The protected range of the ILS is promulgated in the AIP.

[dimmolto]

Alright. Is there anywhere I can read about LVP procedures and calls that may be demanded? What does it actually mean that LVP is on force and what changes are made to minimas and procedures?

And what about the ILS protected range, is it the same for all airports?

[ComJam]

What exactly do you mean by "protected range"?

[HEATHROW DIRECTOR]

Hundreds of years ago in the Air Pilot it would have a protected range for the ILS - usually 10nm. That was the range to which the accuracy of the signal was guaranteed. This has probably changed but I imagine something similar is published for modern ILS systems..

[ComJam]

On Calibrations the furthest out we measure any signal level is 25nm for the Localiser and 10nm for the glidepath.

So I guess that's the answer :ok:

[Gonzo]

At LHR I believe the GP is protected out to 15nm

[dimmolto]

Okay but what do you mean with protected?

[AeroMANC]

CATIII ILS Localiser Sensitive Area is protected 137m either side of runway centreline and as such all aircraft, vehicles and any other temporary obstacles remain clear of this area to ensure the ILS is safeguarded. The ground lighting configuartion will change an the red stopbars will illuminate at the CATIII holds. If I'm not mistken, if an aircraft has not cleared the runway by the time the next arrival is at 4 NM???? then a go-around will ensue. Pilots will report clear of the runway having cleared the alternate amber/green lead-off centreline lighting. As HD stated, airport with SMR have a distinct advantage, at EGCC for example the SMR screen has an LSA overlay to aid controllers. LVP State is broadcast by ATIS, but promulgation by RTF is particularly important on initiation and cancellation of LVP's.....see the attached AAIB Bulletin.

http://www.aaib.dft.gov.uk/publications/bulletins/january_2006/boeing_757_3cq__g_jmaa.cfm

[dimmolto]

Okay, so whats the protected range for CatII?

I assume there is nothing for a CatI.

[ComJam]

Still not sure what you mean by "protected range".

In LVP's aircraft will be vectored onto the ILS far enough apart to ensure the Localiser signal isn't affected for the aircraft behind, the same reason for airfields have "CAT 3" holds even though they may not have a CAT 3 system.

The ILS installation is flight checked for accuracy and signal strength out to 25nm. During a calibration the "protection" required is, generally, 5 nautical miles, i.e nothing between us and the installation when we reach a 5 mile final. That includes nothing taxiing in the Localiser Sensitive Area and nothing departing as an over-flight of the Localiser aerial causes the greatest "disturbance" to the beam.

The same level of protection is required regardless of the Category of the ILS.

[DFC]

ILS covrage in the UK is covered in AIC 34/97 (Pink 141)

Regards,

DFC