yes, absolutely..

still a bit frightening though, that if all that were as we assume here, that engineering at Embraer during development did not catch that one in advance….

but then again…would not be surprised if a review on other aircraft that have the same avionics, or nearly the same, would also show some potential snags / deficits..

GPS is a marvel and has done a lot of good in this world..

however I'm afraid we may have become a little bit too dependent on it, given the known vulnerabilities of the GPS system...

sure, but those that do…? well years ago with earlier generations of IRUs, you did have separate control panels for each IRU, to turn it on, and maybe switch to ATT if one portion of the IRU did not work right and drifted too much or so..

but now with the latest generation of heavy irons, their integrated flight decks with their latest generation IRUs, which are marvels by themselves, you can even align them in flight…, or they will align themselves should for some reason power be lost and the back-up batt not work, they do not have separate control panels anymore..they come on with avionics power..so, do not know, but should some avionics bus go haywire…?

it has gotten pretty involved and "integrated" in that whole flight deck biz….

as Mike correctly stated…too much at times maybe to pinpoint potential problems during development…

P.S.: Years ago, one of those supermodern high tech marvel ultra long range twins ( three IRUs, three FMSs etc etc) suddenly had a dark cockpit in the night, halfway between Hawaii and California, they could not even select a comm frequency anymore ( not that it would have worked..)…good crew sucessfully made it to their destination on a small stand-by instrument and a "walkie talkie…"..was AD stuff, if I remember well a power line for a coffeemaker was installed in the wrong place during outfitting and "killed" a central avionics bus..

From Syberjets Facebook,

GPS NOTAMS got you feeling down?

Did you know that the SJ30i and SJ30x have an inertial navigation system (INS) standard on all aircraft?

We designed the SJ30i and SJ30x to safely operate all over the world, over the water, and during special circumstances like GPS outages or jamming.

"No need to worry about those pesky GPS Outage NOTAMS when you operate our aircraft.

Fly fast. Fly far. Fly Safe."

Do you have any references for the basis of your SIGNIFICANT comment? Everything I've read says the ventral control surface is normally fixed in a trailing position unless being used as a backup yaw damper. Perhaps I missed something.

making the headlines…..

"due to the type's unique geo-dependent flight stability systems…"

http://www.ainonline.com/aviation-news/business-aviation/2016-06-08/gps-interference-testing-encompasses-southwestern-us

does not look like such a strange bird from the outside…

that was a new one for me…

P.S.: remember years ago, at a big outfit outfitting and completing heavy iron jets, the entertainment folks from all companies came with their new "all in one" centralized IFEs..we joked, ha, an IRU or the GPS drops out, the DVD will stop working, and the lav will not flush anymore and the lights will got out..was meant as a joke..( well not such a joke, because we suspected with all this centralized software that indeed some functions may be messed up at times…)

but would have never imagined then that a bird nowadays might have a problem with its flight controls because of a bad GPS signal..

good one...

interesting update here:

http://www.ainonline.com/aviation-news/business-aviation/2016-06-10/aopa-military-scrubs-planned-gps-interference-testing

.

What is not normal is the loss of YD with loss of GPS. That is messed up. There is no reason you can't design a YD system that works without GPS, that's been done for 60 years.

I don't know of any other airplane which has this GPS YD dependency, so this seems to be a problem unique to the Phenom 300 and does not afflict "many others".

Mike C.

Are they ever going to get going on the build? Great plane but when where will it ever be available.

So maybe there will be a big sell off....

Are they ever going to get going on the build? Great plane but when where will it ever be available.

I have no clue why that Phenom is set up like that, and how it works. But what I do not understand is, that, if a jet needs YD redundancy, and a lot of jets need that, why didn't they just put in a small rate gyro for that YD back-up? The simplest thing in the world, and proven in a ton of airplanes..since, like you said, more than 60 years now…

those things nowadays are smaller and lighter than a matchbox and need less power than a small flashlight..

I'd agree with you, that somebody during development was a bit too optimistic, on how much one could make the whole airplane dependent on a given set of sensors..and had not thought of the implications…

and/or, as those Phenom cockpits at least look Garmin 1000 based, that is what Garmin had at the time of development of these planes, that the Garmin 1000 system is a bit taxed output-wise for this kind of aircraft?….in the meantime Garmin has the 3000, and the Part 25 5000 system..and am sure there are a number of reasons for these newer , more capable systems, other than just the touchscreens...

After a period of time with no GPS signal you will get a Blue advisory that AHRS 1 and 2 are operating in a degraded mode because no GPS information is being received. The AFM guidance is now (wasn't always) to slow to below .63M.

Of the many other high speed aircraft. How many of them can stay at altitude with no YD?
I like only having to slow down and not get my range/fuel reserve blown. Would be bothersome over sparsely settled areas or water.

Probably there will be something to address this. As it seems the GPS interference testing will be around for a long time.

I'll have to check my G58. In the hangar, with things on I get a cas that the AHRS is operating exclusively in no GPS mode.
Mike, what will happen if I try to activate the YD?

They can keep their YD operating with loss of GPS.

You seem to be trying to say other airplanes are suffering the same problem but they aren't and the fact the Phenom 300 was *specifically* mentioned in the advisory indicates that.

I'm not aware of any other airplane that requires GPS for YD function. That is the unique weakness of the Phenom 300.

Mike C.