I don't know a lot about GLS, but I do know a fair amount about LPV. LPV has a complex path data record associated with the database for each LPV IAP. If the database "tanks," so does LPV, and for that matter much of LNAV. ILS, OTOH, is fine because it is derived from modern versions of 1945 radio receivers.

then why reply to the thread?

FlightPathOBN:

That was obvious with my answer in context.

Do I detect a bit of hostility from a "friend?"

So, sir, is GLS totally FMS indepentent?

In this case i'm not that sure that the obstacle is the limit. The approach and go-around path of both ILS and GLS are identical and therefore it should be possible to achieve a normal ILS CAT I minimum (current certification limit for GLS) and lateron a normal CAT IIIb limit which is what we have on the ILS. Sad thing is that currently the 737 is not able to follow curved approaches in approach mode, it needs to use LNAV/VNAV for that.

I believe that was the question at the start of this thread. We do not have a definite answer, but apparently it is. The approach path geometry is part of the GBAS datastream and the onboard multimode receiver compares the current 3 dimensional position against that received in the datastream and generates an ILS look alike signal to be displayed on the cockpit display system and to be used by the autoflight system.

Sorry Terpster, I was being flippant...I should have added some :rolleyes:


GBAS is independent of the FMC much like an ILS. If the aircraft didn’t have an FMC (FedEx B-727) you can fly a GLS approach as the data and correction is delivered from the MMR (as it is with an ILS approach).

The FMC offers two benefits to the GLS approach user (as it does the ILS user), ND Map sequencing and missed approach guidance if the missed approach segment is flown in LNAV.

So if you were operating an FMC equipped aircraft on a GLS approach and had a dual FMC failure, it would not impact the approach.

Denti,

without going too far into the chart standards, I do note that the ILS plate shows an MDA, while the GLS chart shows a DA.....

The ILS plate charts the LOCDME as well, which still is depicted with a MDA (shortly it will be a DA as well).

Denti,

If you are doing any more test flights with the GBAS, let me know, I would like to track them on STANLY.

http://operationsbasednavigation.com...NLYBremen1.jpg

Well, it is part of the RNAV transition which is as far as i know at least RNP 1 (our FMC flies it as RNP 0.3), however ATC usually turns you to final early which leaves the transition and makes those nice turns around the intended line. Vectors to final are the norm for airline traffic.


Sadly GLS is officially down and not usable for the time being until it is through the whole certification process. I have to add though that EDDW is one of those places we do not visit all that often anyway, other operators use it more often, lufthansa has based the CJ1s of its flying school there.