Loss of GPS satellite signal while approaching in IMC

[xblueh2o]

I wonder if any of them ran a RAIM prediction.
I wonder, can you look for historical RAIM data? I only know about looking forward.
There is a famous story where a guy with a GPS jammer in his work truck fouled the LAAS beacon at Newark.

[lr172]

Originally Posted by FORANE

He's probably referring to not having to hit the OBS button to switch from GPS to ILS on the CDI.

I believe the CDI button is used to switch from GPS to VLOC. The OBS button is used for OBS mode or un-suspending, such as after the MAP on an approach to start the missed appr sequience.

Larry

[FORANE]

Originally Posted by lr172

I believe the CDI button is used to switch from GPS to VLOC. The OBS button is used for OBS mode or un-suspending, such as after the MAP on an approach to start the missed appr sequience.

Larry

Ah, yes, you are correct.

[GalinHdz]

Originally Posted by xblueh2o

I wonder if any of them ran a RAIM prediction.
I wonder, can you look for historical RAIM data? I only know about looking forward.

What is predicted and what actually happens can be two very different things.

[Pilot135pd]

Originally Posted by GalinHdz

What is predicted and what actually happens can be two very different things.

Correct but it would be interesting to see how well the computers predicted it and on a less important note how well those guys did their preflight planning.

[Ed_Wischmeyer]

Somebody will undoubtedly correct me on this if I'm wrong (again), but my understanding is that WAAS means that RAIM is not required. And based on hazy recollections of technical articles that I only sort of understood, there are lots of ways of doing RAIM, depending on how that individual GPS receiver processes the GPS signals to get a position.

And it might also be the case that although signal quality was not good enough for an approach, there were enough GPS signals to allow basic navigation.

Lotsa details...

[GalinHdz]

Originally Posted by Pilot135pd

Correct but it would be interesting to see how well the computers predicted it and on a less important note how well those guys did their preflight planning.

Two independent and completely different aircraft having the same issue at the same time in the same airspace reduces significantly the posibility of crew error. Both airplanes landed safely without a problem so both aircrews executed an effective alternate plan.

Lets not fall in to the "just blame the pilot(s)" syndrome we complain the FAA is too quick to do.

[Pilot135pd]

Originally Posted by GalinHdz

Two independent and completely different aircraft having the same issue at the same time in the same airspace reduces significantly the posibility of crew error. Both airplanes landed safely without a problem so both aircrews executed an effective alternate plan.

Lets not fall in to the "just blame the pilot(s)" syndrome we complain the FAA is too quick to do.

Not what I meant, maybe I used the wrong terms to express myself. I meant that we can see if the computers who predict these outings were correct or not and just because 2 planes had the same issue doesn't mean they both didn't do the preflight correctly. What if they both used foreflight so they didn't have a need to check anything else? It's not always about the pilots being wrong, these things might bring up forflight for example being wrong.

[Walt]

Originally Posted by Desert Rat

Walt. To make sure I'm understanding you correctly; If I select an LPV approach and the GPS tanks, the 650 will automatically kick over to an ILS for the same runway?

I've got a ton of time with a G-1000 and don't recall ever discovering this. Have I just not got deep enough in the book or is this specific to the 650/750?

I did not mean to imply that if you lose GPS it will auto switch to an ILS on it's own, but when a runway has both an ILS and a GPS though I try to make it a habit to have the ILS tuned so if I lost the GPS I could manually switch over by hitting the CDI button and grab the needles.

My point was have an ILS as a backup makes me feel good.

[LR60]

Walt,

I'm interested in why not recommend the GTX 375 paired with a GNC 255A Nav/Com. This would provide dual nav along with dual source and is several AMU's cheaper than the GTN 650.

I realize the 650 has a few more bells and whistles that the GTX 375 doesn't but what am I missing because I haven' seen this combo in panels. I'm about ready to order my panel and can't decide which path to take regarding this very topic.

Your thoughts?

Thanks

Mark