ahw01
Well-Known Member
Rather Interesting... Nice typo...
http://www.faa.gov/regulations_poli...fm/go/document.information/documentID/1029348
http://www.faa.gov/regulations_poli...fm/go/document.information/documentID/1029348
EMB-300 Phenom Yaw Damper Fail Due To Unreliable OR UNAVALIBLE GPS SIGNAL
- Thread starter ahw01
- Start date
undflyboy06
Well-Known Member
ATC asked us about this yesterday. We didn't think that was possible. I am actually really surprised by this.
averettpilot
Well-Known Member
Is this something confined to the 300 or could it cross over with the 100? From what I've heard they have pretty much the same avionics/systems.
CoffeeIcePapers
Well-Hung Member
JeppUpdater
Well-Known Member
Strange.
I flew a 100 in an area of complete GPS outage Friday (courtesy the US government...thanks guys) with zero AP or YD issues. There's no reason they should be connected, but I'll do some digging.
I flew a 100 in an area of complete GPS outage Friday (courtesy the US government...thanks guys) with zero AP or YD issues. There's no reason they should be connected, but I'll do some digging.
TUCKnTRUCK
That guy
The GPS provides the AHRS with Lat/Lon info, which is used to correct and check the magnetic info. The loss of signal reverts the AHRS which causes the failure. The YD needs the AHRS input to function, and will disconnect with unreliable data....
As I understand it though, you would also need to be out of DME/DME/VOR service areas though...
Or so it goes in other planes.
As I understand it though, you would also need to be out of DME/DME/VOR service areas though...
Or so it goes in other planes.
TUCKnTRUCK
That guy
I do believe that many airplanes with 3 axis YD's and no IRS may have the same issue...
jtrain609
Antisocial Monster
The joke, you missed it.
TUCKnTRUCK
That guy
Nah, I was just being a pain in the ass
.
Roger Roger
Bottom of the list
I'm curious why the AHRS don't have a non-GPS mode. I know our AHRS (yes, I realize it's sort of apples to bananas) doesn't care about GPS. From my limited understanding there's no reason either a MEMS or an RLG AHRS with a magnetometer needs GPS to get at least a good-enough magnetic heading. It'd be interesting to know the deep details behind this.
TUCKnTRUCK
That guy
Lat/long allows it to correct the Mag gates for position based errors. It's not that it won't function without, but reverts to a lessor state.
(Garmin Graphic)
TUCKnTRUCK
That guy
Lat/long allows it to correct the Mag gates for position based errors. It's not that it won't function without, but reverts to a lessor state. I'm assuming the Phenom YD won't accept a reverted state, as the heading input would no longer be corrected?
Either way, with an FMS capable of DME/DME, and IRS or other position reporting system should prevent this from happening even with a loss of GPS, so- I would assume this only happens outside of VOR range, or there is a issue in the avionics
(Garmin Graphic)
Roger Roger
Bottom of the list
My guess (again, I'm only familiar with a single, very primitive system) is that in the no-GPS "degraded mode" or whatever the AHRS throws an error code or message saying its degraded. Probably the same code for a variety of errors, some of which would be a good reason to kick the YD off, but whoever programmed that functionality didn't consider the effects of this particular error (which shouldn't prevent the YD from working) on the system. Still a pretty stupid chain of events though.Lat/long allows it to correct the Mag gates for position based errors. It's not that it won't function without, but reverts to a lessor state.
(Garmin Graphic)
Congratulations, you have discovered Phenom logic!
Roger Roger
Bottom of the list
No brakes for you!Congratulations, you have discovered Phenom logic!
