Microwave vs. ILS

I assume you are talking about MLS vs ILS

MLS has more flexibility in siting criteria. MLS can be more accurate. ILS has more RF vulernabilities.

ILS is still in use. MLS didn't quite catch on.
 
I digging way back in my memory here, but wasn't there something about arcing onto the final with an MLS?
Are there even any MLS's in the U.S.? Other countries? I thought they scrapped that program many moons ago.
 
thanks... I remember learning about it during the Instrument training and having to answer the questions on the FAA written...

Some co-workers and I were talking about the MLS this morning and I just couldn't recall a single thing about it...

Thanks, Blue skies!
 
jDidn't the shuttle use the MLS for landing?
 
GLS is the future. Sort of like WAAS but it uses local area augmentation. I believe the reference station has to be within 25 miles of any airport that will use it.

Supposedly, GLS will support CAT II and III. Both EWR and IAH have it now for use by Continental/United.
 
re. the OP, one big difference is frequency: 5000 MHz for microwave vs 100 MHz for ILS. Other differences include the physical layout of the transmitters on the airfield, and the range of angles that they can be received (ILS is more limited, regarding where you can receive a useful signal).

MLS approaches were installed in a couple of airports in northern Europe, where the ceilings are often low. Including Heathrow. I'm not sure if they are still in use.

Microwave avoided some of the problems of ILS, such as a limited range of angles the signal could be received. But when GPS/WAAS became widespread it became clear that GPS approaches would be far cheaper to implement, and they would also succeed in avoiding the problems of ILS that MLS sought to solve.

More elaboration on ILS vs MLS here:
http://en.wikipedia.org/wiki/Microwave_landing_system
 
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The MLS is explained in AIM Section 1-1-11, but I think the last two MLS approaches in the US either were or will soon be decommissioned. And I think they took those questions out of the IR-A written test question bank.
 
You can't make popcorn with an ILS.

Yes, thankfully the MLS questions are finally gone. Maybe they can nix the SDF questions now.
 
As I remember it MLS was the looming NexGen for about 25 years then pffttt...I know Polaroid had been working hard on developing instant movie film but then things just jumped the shark. When people mention the Shuttle I get sad, wish I had gotten to see at least one launch. :nonod:
 
Don't believe Andersen has their MLS anymore. Also according to the proposed IAP decommissioning survey the FAA sent out, there are 0 MLS approaches in the U.S. Still 11 SDF approaches.
 
Yeah, but still not really enough to write trivia questions on the IFR written. In fact, the SDF question is one of the typically horrendous ones on the exam that has NO real right answer. It's the fact that the FAA has the utterly horendous drivel that you won't get any argument on me on people craming the questions rather than learning for the test. If you knew everything that there is to know about LDAs and SDFs, you'd still have to eenie-meenie-miney-moe two of the answers on this.

While there may be that many SDFs with published plates, I think you'll find that at most there are only two operational.
 
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When the AF upgraded the avionics in the KC-135 to CNS/ATM, they installed MLS equipment in all the airplanes. We trained ad nauseam on them in the simulator, and it was a PITA to set up and fly. But, then again, it was the AF so the setup we have is probably 1000 times harder than it really needs to be. I, for one, am glad that the MLSs faded away.
 
The MLS is explained in AIM Section 1-1-11, but I think the last two MLS approaches in the US either were or will soon be decommissioned. And I think they took those questions out of the IR-A written test question bank.

Back when, didn't they put an MLS in at Reagan 19 so as to do a multi-leg localizer around the monuments?
 
I believe a couple of the earliest MLS approaches were private ones installed by Rocky Mtn Airways up in the rocks. The Dash-7s were the last aircraft outfitted with them, I believe, and the later ATRs were not and the approaches were shut down.
 
Back when, didn't they put an MLS in at Reagan 19 so as to do a multi-leg localizer around the monuments?

Runway 18 at National to keep you over the river, primarily for noise rather than "dodging" monuments. The approach mimiced the existing "river visual." I'm not sure it actually ever got operatinally used. It did get used in lots of studies.

There was a similar MLS overlay of the Canarsie approach path into JFK.
 
The MLS in Heathrow is still very much in use.


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Runway 18 at National to keep you over the river, primarily for noise rather than "dodging" monuments. The approach mimiced the existing "river visual." I'm not sure it actually ever got operatinally used. It did get used in lots of studies.

There was a similar MLS overlay of the Canarsie approach path into JFK.

The RNP approach for Runway 19 at KDCA satisfies the requirement to mimic the River Visual in IMC.

So far, the airspace constraints at KJFK have precluded a public RNP approach for Runways 13L/R. I believe Jet Blue has a special issuance RNP approach for those two runways, but I am not sure it is used. When the weather and wind dictates Kennedy configures for the ILS 13L, which precludes Jet Blue from using their special RNP approach (if they still even have it in their ops specs).

MLS is dead for all practical purposes. GLS is the wave of the future for air carrier "all weather" operations. But, that is not the near future except for the limited GLS operations at Newark and Houston International.
 
The GLS mins at EWR look no different than LPV mins would be. What's the advantage?

Is it that they're going to certify them to Cat III mins, but it just hasn't been done yet?

Are there any GA level navigators that can fly a GLS?
 
The GLS mins at EWR look no different than LPV mins would be. What's the advantage?

Is it that they're going to certify them to Cat III mins, but it just hasn't been done yet?

I believe that is the case. Local augmentation provides integrity and redundancy below 200 feet that LPV lacks.

Are there any GA level navigators that can fly a GLS?

Not that I am aware. I doubt it matters.
 
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