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MD83FO
3rd May 2015, 18:43
When I deselect a satellite on predictive GPS is it effectively deselected for navigation or just for the prediction.

deptrai
3rd May 2015, 22:04
On a Honeywell FMS it's deselected for both prediction and navigation. Since the point is to remove a bad satellite, imho it wouldn't make sense to be able to deselect it only for prediction but then use it for navigation.

sonicbum
4th May 2015, 08:21
According to FCOM DSC-22_20-50-10-25 (Honeywell FM) it mentions only predictions, but I agree on the above, it would not make sense to have a satellite deselected for predictions but still used for navigation.

Edit : The satellites exclusion is performed by the MMR (Honeywell). Hence the ones remaining can ensure the required HIL and are thus usable for navigation.

deptrai
4th May 2015, 09:00
if you're looking for a more authoritative source than anonymous posters, here's a snippet from Honeywell (about 9100HT , I can only speculate if the same applies to their other systems, but my guess is yes it does :) )

After deselecting a satellite on the ground for the FDE test, is this satellite only deselected for
the test or is it also deselected for navigation?
It is also deselected for navigation. The system requires a way for the pilot to also deselect a
satellite that is bad. Therefore, if the pilot is aware of a bad satellite (e.g. from NOTAM
reports) then the pilot would enter the bad satellite number in 5L. The satellite will then not
be used for the FDE check and it will also not be used in flight for navigation.

http://www.honeywell.com/sites/servlet/com.merx.npoint.servlets.DocumentServlet?docid=D301F371D-EE74-A8B2-D111-08B58C468A08

I-2021
4th May 2015, 11:07
deptrai, you are an anonymous poster too. The purpose of the tech section of this forum is to exchange informations and opinions between pilots all over the world who can bring different levels of accuracy and reliability in their contributions. I would refrain from using this kind of sarcasm towards members that are trying to bring in some help, because you never know who is writing behind a nickname. It is obviously much more effective to provide links as you did and references to official material, but this does not mean that people can not share their points of view if they comply with the rules of engagement and are active industry professionals.

Cheers.

deptrai
4th May 2015, 11:52
Please accept my apologies. I mentioned "sources" because the previous poster very professionally referred to the FCOM, and I hadn't given any sources in my first post. Therefore I followed up with a source. My sentence about sources and anonymous posters was aimed solely at myself, and meant as an apology for not having been able to post a source previously, in this context where sonicbum did provide a source. It was not intended as sarcasm, and not directed at others. Clearly I didn't manage to express this. My mistake, and I sincerely apologize.

I-2021
4th May 2015, 13:09
No worries deptrai it's all sorted ;-)

Amadis of Gaul
5th May 2015, 10:31
The purpose of the tech section of this forum is to exchange informations and opinions between pilots all over the world who can bring different levels of accuracy and reliability in their contributions.

That may well be the purpose, but does that make it the reality?