ILS quality for autoland

[737incognito]

Does anybody knows what kind of quality should ILS that's not cat II/III approved have in order to be used for autolands. I would appreciate any reference in documents that I can research further. Thanks

[extreme P]

A CAT I ILS will provide an acceptable autoland BUT you will not have guaranteed protection from such events as vehicles driving in front of the localizer shack.

http://www.faa.gov/library/manuals/e...4/4_002_06.pdf

Do some searching here and I'm sure you will find what you are looking for.

[relax.jet]

Any CAT I ?

I was told that it is approved for every CAT I instalation which is certified. But! using it for CAT I autoland, you should be aware, there might be some unusual autopilot behaviour when LOC or GP signal is disturbed (no protections as during LVO). If I need it, I`ll use it, that`s it.

[angelorange]

CAT3 ILS roll out guidance is checked every 6 months in JAA countries by flying at 50 feet in a special role BE20 - see www.flightprecsion.co.uk
A vehicle driving in front of a CAT3 ILS WILL affect the localiser signal and if close to the Glide Slope array (approx to one side of PAPIS) then that will be affected - no problem for a seasoned manual flyer but some autopilots may trip out.
CAT3 has extremely good reflection surface ahead of the runway threshold to ensure a very smooth glideslope signal.
Note that over the last 200 feet or so on the deccent the G/S signal is also affected by snow on the ground / water (eg: rwy closest to sea at Barcelona, Leuchars etc) (ie: on that reflection surface).

[fokkerjet]

Tell ATC you are going to do an autoland and ask for the ILS to be protected; that seems to solve the problem

During low vis, it's protected automatically.

[411A]

Having done over 400 automatic approach/land (autoland) maneuvers in the 'ole L1011, not once did I have to disconnect the autopilot(s), or have a 'tip off' due to vehicles, aircraft etc on the runway, or near thereto.
With autolands, there is nothing better than the 'ole Lockheed tri-motor....bar none.
It simply doesn't get any better, even though the design is well over 30 years old.
Smooth, smooth...smooth, and supremely accurate.
Ah...Lockheed

[flyboyike]

Originally Posted by 411A

With autolands, there is nothing better than the 'ole Lockheed tri-motor....bar none.

I think you've established by now that, according to you, nothing is better than the ole Lockheed tri-motor, autoland or otherwise.

[Capt Pit Bull]

Many Cat 1 installations are suitable, because it is the absence of redundancy / lighting / LVPs etc rather than basic signal quality that is making that runway / ILS cat 1 rather than higher.

However, not all Cat 1 installations are suitable. They need to be within certain ranges of glide slope (I forget them, off the top of my head, but something like 2.6 to 3.5 but that might vary by aircraft, not sure). Certainly autolanding at somewhere like MRS (?14R IIRC 4.1 degrees) would be a bad call.

Also offset localisers are a no go for obvious reasons.

Anywhere with notams / ATIS etc that warns of unsuitability. e.g. somewhere like DUS during parallel runway ops, or anywhere with particular signal / topography issues.

pb

[PantLoad]

SOP

My company's SOP is: (in order to do autolands)

1. It has to be a CAT II/III installation, and
2. There can be no NOTAMS prohibiting autolands (e.g. signal degradation due to snow piles, or ground equipment problems, etc.), and
3. The crew must be properly trained and current in the performance of autolands, and
4. The aircraft must be certified for autolands (no MELs, etc.), and
5. ATC must be informed that an autoland is requested, thereby requiring critical areas to be protected.


Under the above circumstances, we can do autolands all day and all night...to our heart's content.


PantLoad

[alf5071h]

Beware those airports with an unqualified terrain profile during the last 100ft of the approach. Although autoland systems are tested for problems caused by ditches, walls, etc there are limits as to how much a system can take.
ATC must be informed, but they may not be able provide any protected area. IIRC there was a serious incident involving an MD 80 practice auto land at Gatwick when a departing aircraft overflew the LOC aerial and caused a major LOC / roll disturbance.

411A obviously hasn’t flown an Avro RJ autoland!

[chevvron]

RAF ILS installations may not conform to Cat 1 hence none* are approved for autolands.
*But there may be some which are approved!!

[F4F]

Technically you can do an autoland on any ILS.
But beware as some aircraft manufacturer do require CAT II/III quality beam to have them done, so, to be on the safe side, check your AFM

[Graybeard]

At least in the US, last I knew, the ILS beams are not protected except in IMC, or by request.

Stockton, Calif, was a favorite for autolands by McDouglas, although they had a disturbance of the LOC once in awhile. Finally one day, they correlated the disturbance with a large truck on the road just beyond the airport, as it passed by the back side of the airport's localizer antenna.
GB

[SR71]

JAR AWO (specifically ACJ AWO 181(f) ) makes mention of how some ILS installations are not suitable for autolands.

The applicable document that governs the tech specs of a JAR compliant ILS is (as I understand) EUROCAE ED46/47 but I have never seen a copy.

My supposition is that this document would contain the relevant tech explanation for the JAR warning.