Mooney Bravo

[MIm20c]

I agree with GB with many of his points. Here is a rnav plate from my home airport. There have been multiple weather conditions where the LNAV brought plane to pavement vs the missed roller coaster ride of the LPV DA. 

[GeeBee]

11 hours ago, carusoam said:

GB,

1) are you sure Garmin has them in stock?

There are threads around here saying something different...

2) are you comparing WAAS approaches to ILS approaches...?

My home drome doesn’t have an ILS... so the difference between a WAAS approach and a VOR based approach would be many many 100s of feet...

Just trying to understand your points...

Best regards,

-a-

If they don't have them in stock, I just wrote a big check for nothing and a box of rocks from Garmin just arrived at the shop.

No, I am comparing a WAAS LPV approach to an LNAV approach. As I said, it is usually only a 100 or 200 feet and the times that will make a difference is rare in occasional use.

As I said, everyone's situation is different. Your situation may require WAAS. How often is your airport below LNAV minimums?

I will tell you this, I know of several airlines taking delivery of brand new wide bodies, with WAAS equipped FMS and their operations specifications do not include LPV approaches? Why? Not worth the money to train and certify. Their calculation is LNAV minimums are good enough. Now you can say yeah but they go to ILS airports and you would be correct. Except they take the time and money to train and certify for CATIII ILS approaches. Now the number of times I have shot an actual CATIII (that is the wx was severe enough to require it) in a 40 year career is maybe 20? I've seen a lot of CAT II or CAT I to minimums but real CATIII is rare. For the last 15 I was flying into London, Amsterdam, Stockholm etc. The airlines do a very tight business case for everything they do and it does not take a lot of diverts to sell an approach and still LPV is a hard sell.

 

[exM20K]

2 hours ago, GeeBee said:

No, I am comparing a WAAS LPV approach to an LNAV approach. As I said, it is usually only a 100 or 200 feet and the times that will make a difference is rare in occasional use.

I don't think people consider this enough.  Yes, resale is helped with WAAS, but for a plane you're planning to keep for a long, long time, careful weighing of "nice" vs "need" to have is important.

[HXG]

The non-WAAS G1000 Bravos are still outstanding,  very capable airplanes, but personally WAAS accuracy and advantages are important to me when I’m spending that kind of money on an airplane.  As far as “don’t need WAAS”, I don’t need an airplane either, but I like having the most capable airplane for my missions and budget.  Resale should also be considered when purchasing any airplane. 

[larryb]

I believe there are also problems with non WAAS G1000s not showing all approaches due to old software. Something to do with the VDP angle set to 0. It is a big problem when you can’t upgrade the software over time.

[exM20K]

54 minutes ago, larryb said:

I believe there are also problems with non WAAS G1000s not showing all approaches due to old software. Something to do with the VDP angle set to 0. It is a big problem when you can’t upgrade the software over time.

WAAS units, too. 

[GeeBee]

If you don't have a glide path angle defined in the data base, you shoot a standard LNAV approach and you fly it like any other non precision approach.

 

 

[larryb]

The approach is simply not in the database at all. Nothing to fly.

 

https://www.beechtalk.com/forums/viewtopic.php?f=21&t=168806

[GeeBee]

Restricted Forum but that said, the reason why it is not in the data base can be a lot of things. The Jeppesen data base seems to have more than the FliteCharts. Why? I don't know.

 

 

[larryb]

You can join for free. Lots of good info there.

[larryb]

https://www.garmin.com/en-US/aviationalerts/service-advisory-1372-rev-b-unavailable-rnav-gps-approaches-due-to-lack-of-vda/

[carusoam]

GB,

Thanks for sharing the details...

The BT site is a good place to go to get Garmin specific info...

For some reason... Trek Lawler the on line Garmin Guy has decided to spend a lot of his time over there.

Every now and then some info will get shared via a link around here... it is easy if you have the credentials already...

Best regards,

-a-

[GeeBee]

Thanks for the tip. I will go over and lurk on the BT site.

As far as the link goes, that is a data base issue, not a hardware issue and if you notice it affects not just G1000, but GNS and GTN units as well. Data base issues are common and usually fixed quickly because it is a coding issue, not a hardware problem. Happens to the big boys too. 

 

\

[larryb]

It is a software issue. If you have a GTN then you update the software and you are good to go. If you have a G1000 you cannot update the software without the airframe manufacturers testing and approving it. And the airframe manufacturers often do not do this. There are many G1000 systems flying around with decade old software and the owners cannot get them updated.