Departure with non-functional "glass" legal?

P

peter-h

Line Up and Wait
Joined
Sep 24, 2007
Messages
613
Location
UK
Display Name
Display name:
peter-h
Presumably, a VFR departure is legal because there are sufficient backup instruments to meet the type certificate requirements for day VFR.

Is that always the case? What if the LCD which has packed up is the one carrying the primary engine instruments?

However, I can't see IFR being legal unless one also has a separate GPS (normally the case with a G500/600) and a CDI mounted within the pilot's immediate field of view.
 
peter-h said:
Presumably, a VFR departure is legal because there are sufficient backup instruments to meet the type certificate requirements for day VFR.
Click to expand...
First, let's separate the "type certificate requirements" (essentially, what it tells you in the AFM's Kinds of Operations paragraph in the Limitations section and in the Equipment List part of the W&B section) from the 91.205(b) equipment requirements for Day VFR flight. The only flight instruments required by 91.205(b) are the airspeed, altimeter, and mag compass, and those should be covered by the "standby" instruments, but others may be required by the AFM even for Day VFR flight. They only way to know what those are is to look at that aircraft's AFM.

In addition, it would depend on just what "glass" is/is not working. For example, the engine instrumentation may be on one of the displays, and if that display is out, you may not have the required oil pressure/temp indicators, and then even Day VFR would be prohibited by 91.205(b).

However, I can't see IFR being legal unless one also has a separate GPS (normally the case with a G500/600) and a CDI mounted within the pilot's immediate field of view.
Click to expand...
I don't know of any "glass panel" plane whose AFM permits IFR operation with either the PFD or MFD inoperative. If nothing else, loss of the PFD generally means loss of the only gyroscopic rate-of-turn indicator display, and that is required by 91.205(d)(3) for IFR operation.

All in all, the answer to this question would normally be found in the AFM as described above. Beyond that, you're probably looking at a special flight ("ferry") permit for a one-time flight to a repair station in Day VFR only.
 
Last edited:
peter-h said:
Presumably, a VFR departure is legal because there are sufficient backup instruments to meet the type certificate requirements for day VFR.

Is that always the case? What if the LCD which has packed up is the one carrying the primary engine instruments?

However, I can't see IFR being legal unless one also has a separate GPS (normally the case with a G500/600) and a CDI mounted within the pilot's immediate field of view.
Click to expand...
What does the equipment list for that airplane say?
 
For me it is hypothetical, as I don't have a glass cockpit.

I just wondered how people manage when they get a failure and there is no Garmin or whatever authorised dealer around. I have to say that when I do my long trips across Europe, I see very few modern airplanes. I see a lot of old Cessnas, Mooneys, etc. I don't see people doing long trips in new SR22s, etc. Yet, a lot of SR22s have been sold - approx 200 in Europe.

I have a suspicion that after you have had a few gremlins with your avionics (of the sort that would cause major hassle) you will think twice before doing a long trip. Not an issue in the USA, where the list of avionics facilities is as long as your arm...
 
There are a lot of SR22s sold. I rarely see a Cirrus on my long trips, either, yet when I check FlightAware there are about 4x more SR22s in the sky right now than 310s and Aztecs combined.

Kinda scary to me...
 
peter-h said:
I just wondered how people manage when they get a failure and there is no Garmin or whatever authorised dealer around.
Click to expand...
I imagine they consult the AFM, fly it to the shop if they can do so legally per 91.213(d), or get a ferry permit if they can't.
 
Ron Levy said:
I imagine they consult the AFM, fly it to the shop if they can do so legally per 91.213(d), or get a ferry permit if they can't.
Click to expand...
That's one of the reasons the G1000 have the reversion mode that can be manually selected. If the only problem is the display unit - push the button and the other unit comes up with what you need to keep flying.

On the other hand, if the problem is in the sending unit (ADC, AHRS, Engine monitoring) then you're back to being grounded until you get it fixed or a ferry permit, just as you would if the same functions failed with mechanical instrumentation.
 
TMetzinger said:
That's one of the reasons the G1000 have the reversion mode that can be manually selected. If the only problem is the display unit - push the button and the other unit comes up with what you need to keep flying.
Click to expand...
You can keep flying, yes, but the question would be whether you can legally depart with the display in reversionary mode.
 
Everskyward said:
You can keep flying, yes, but the question would be whether you can legally depart with the display in reversionary mode.
Click to expand...
And for that we go to the AFM - I'll have to look next time to see whether both displays are on the required list for the various types of operations.
 
Ted DuPuis said:
There are a lot of SR22s sold. I rarely see a Cirrus on my long trips, either, yet when I check FlightAware there are about 4x more SR22s in the sky right now than 310s and Aztecs combined.

Kinda scary to me...
Click to expand...
What is scary about it? It might be regional. I see a lot more Cirrus then I do 310s or Aztecs.
 
TMetzinger said:
That's one of the reasons the G1000 have the reversion mode that can be manually selected. If the only problem is the display unit - push the button and the other unit comes up with what you need to keep flying.
Click to expand...
That can keep you flying safely if the pilot's display dies in flight, but I doubt it's legal to launch IFR that way -- the AFM, however, would tell you for sure.
 
TMetzinger said:
And for that we go to the AFM - I'll have to look next time to see whether both displays are on the required list for the various types of operations.
Click to expand...
I know in our plane we cannot take off with any of our 4 screens inop, missing or in reversionary mode.
 
TMetzinger said:
And for that we go to the AFM - I'll have to look next time to see whether both displays are on the required list for the various types of operations.
Click to expand...
I found a C-172S IM on line:
http://www.uofmflyers.org/pdfs/172SIMAUS-03.pdf

If you go to page 2-14/15, you'll see that either the PFD or the MFD must be operating with at least with the airspeed, altimeter and engine instruments for even Day VFR, and except for the VSI readouts, both PFD/MFD and the standby instruments must be fully operational for IFR.

Of course, the rules for an Avidyne or G600 or any other "glass panel" display system might be different.
 
Looking at the Diamond DA40, the Supplement for the G1000 requires both PFD and MFD to be operational... you can get away without the AHRS for Day VFR.

Interesting how the two manufacturers came to different requirements.
 
NO. You can not depart with out the PDF and engine instruments up and working. That applies to all G1000 Cessna's
 
TMetzinger said:
That's one of the reasons the G1000 have the reversion mode that can be manually selected. If the only problem is the display unit - push the button and the other unit comes up with what you need to keep flying.

On the other hand, if the problem is in the sending unit (ADC, AHRS, Engine monitoring) then you're back to being grounded until you get it fixed or a ferry permit, just as you would if the same functions failed with mechanical instrumentation.
Click to expand...
The Reversion mode will go to PFD or MFD if one dispay is not working, there would be no reason to press the button. You can not get a display to be a MFD unless it sees a complete PFD up, by the either net.
 
The problem also has another, non-legal side to it. For example, I flew on round-gauges for 9 years, and only half a year ago started flying the G1000 Cessnas. For me, using the "old" instruments for a daytime VFR flight wouldn't be so bad. I was taught real pilotage first--map, compass, watch, eyes--and you can use that in a simple plane, in nice daytime weather, to get from here to there without anything else.

How are primary students taught? It has to be too tempting to learn only the absolute minimums of pilotage with that big G1000 PFD and MFD right in front of you? If that goes away for someone brought up on that, it might be a totally different world!
 
I have no issue with continuing a flight following an in-flight failure (at least, it's a very different question); it is purely the legality of a departure with the stuff INOP on the ground, and assuming somebody has been notified so you can't pretend it happened in the air
wink2.gif


I like the G1000 too; I have 1.5hrs in a TBM850 with it, and didn't have the slightest issue with it.
 
Ron Levy said:
Funny thing is, that's not exactly what it says in the C172S Information Manual cited above.
Click to expand...
Check the POH and it has it in the Limitations list KOEL 2-10. You can with the MFD in rev. Mode showing it as a PFD.

"PFD backlight must be working, if not MFD must be in rev. mode showing engine instruments for day VFR."
 
Last edited:
Gsim Aviation said:
Check the POH and it has it in the Limitations list KOEL 2-10. You can with the MFD in rev. Mode showing it as a PFD.

"PFD backlight must be working, if not MFD must be in rev. mode showing engine instruments for day VFR."
Click to expand...
That's what I said originally. Then you said the PFD must be working. Do we now agree that Day VFR is legal in the 172 with only the MFD working (in reversionary mode)?
 
Ron Levy said:
That's what I said originally. Then you said the PFD must be working. Do we now agree that Day VFR is legal in the 172 with only the MFD working (in reversionary mode)?
Click to expand...
Like I said the PFD has to be working to take off, if the MFD is in rev. Mode it IS the PDF. You will not have a MFD if it is in rev mode. Only PFD and engine instruments, there will be no MFD only a small inset map and you will have no ground speed info.

Quote:
Originally Posted by Gsim Aviation
NO. You can not depart with out the PDF and engine instruments up and working. That applies to all G1000 Cessna's
Funny thing is, that's not exactly what it says in the C172S Information Manual cited above.

We are on the same page!
 
Last edited:
Everskyward said:
I know in our plane we cannot take off with any of our 4 screens inop, missing or in reversionary mode.
Click to expand...

Interesting, we have 5 screens and can take off with one inop provided it is the center display, and like you, no go if in 2 of the 3 reversionary modes (we can take off with one DCU). That is according to the FAA MEL, the Canadian one allows takeoff with only 3 screens operational provided the two inop are the center and copilot inboard displays.

I wonder what the deal is with 4 screens and the FAA or is it just a coincidence between our two very different aircraft?
 
Laurie said:
I wonder what the deal is with 4 screens and the FAA or is it just a coincidence between our two very different aircraft?
Click to expand...
I'm guessing it's just the way they were certified. Our avionics are Honeywell but I don't know if that makes a difference.
 
You must log in or register to reply here.
Back
Top