Partial Panel G1000: Cessna vs. Cirrus

Discussion in 'Pilot Training' started by Thunderbird83, Feb 11, 2019.

  1. Thunderbird83

    Thunderbird83 Filing Flight Plan

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    I'm a CFI, working with my first instrument student... Training him in a G1000 Cessna 172.

    I am ready to start doing simulated "partial panel" work. I have previously done partial panel in a Cirrus SR22T, and the manufacturer recommended process was a simple (and very realistic) pulling of a circuit breaker to simulate the desired failure.

    Cessna recommends against pulling the circuit breaker to simulate partial panel, as they say using the circuit breaker as a "switch" can cause premature wear and failure of the breaker. The Cessna recommended partial panel procedure is to dim the screen on the PFD.

    I looked back through my training manuals from Cirrus, and I found a section regarding the life of a circuit breaker. Cirrus strongly advocates that only realistic way to simulate partial panel is to pull the circuit breaker, and the duty life of a breaker is 5000 cycles. They say in their training literature that this limit is unlikely to ever be reached, even in an aiplane used for training.

    Garmin also has a document on recommended procedures for training in G1000 airplanes, and they also recommend pulling breakers in all airplanes EXCEPT for Cessna. For Cessna, they say dim the screen because the manufacturer says so.

    Why is Cessna the only manufacturer that discourages using the circuit breakers? To me, simply dimming the panel is not a realistic way to prepare a student for loss of AHRS or ADC... I'd prefer to present the actual failure. Are Cessna circuit breakers too fragile to be cycled a few times?

    How do you simulate partial panel in a G1000 airplane?
     
    Last edited: Feb 11, 2019
  2. DGlaeser

    DGlaeser Pre-takeoff checklist

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    I use a full size AHRS failure screen mounted on cardboard. Cut out the holes for the knobs at the top and it slips on. You cut out the slot for the glideslope and the center of the HSI for the CDI. Garmin recommends mounting it on a foam backed cardboard.
    You can find pictures online and print them out.
     
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  3. Tantalum

    Tantalum En-Route

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    Dimming the panel is not a real simulation. When you lose an MFD / PFD the whole layout changes, etc... it doesn't just go dim. Teaching students incorrectly, in my book, is life threatening. This is like simulating a stall by never actually stalling it, just having your CFI whistle into the headset "oh Timmy, here's your horn!"

    AGREED! For all the hate Cirrus gets they're more than happy to put their planes through the paces to ensure realistic training

    ..and my gratuitous "yet another reason why I hate Cessnas.." mini rant
     
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  4. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    Pull the damn breaker. Cessna's recommendation was written by someone who didn't know ****, apparently.

    When this recommendation came out, I think it was @gismo who looked up the actual parts Cessna uses, and found that those breakers had exactly the same duty cycle as the switches from the same manufacturer that Cessna also used.

    So, forget Cessna's silly recommendation. Pull the breaker, and the breaker will last just fine.
     
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  5. BillTIZ

    BillTIZ Final Approach

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    Flew with a DA40XLS owner. He pulls the CB
     
  6. asicer

    asicer En-Route

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    Seems to me that if the breaker fails the first few times you pull it then an experienced CFII is on board to save the day. If the breaker fails the 10th or more time you pull it then the pilot in the left seat will have been sufficiently trained on what to do. No problem, right? :)
     
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  7. IK04

    IK04 Cleared for Takeoff

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    Back in the old days when the Arrow was a trainer for the commercial requirements, we habitually pulled the gear warning system breaker on every takeoff, especially short field takeoffs.

    You see, Piper thought it was a good idea to automatically lower the landing gear below a certain speed, somewhere around 70 knots- in case the pilot forgot to put the gear down. The problem with that was the complicated system of switches and relays would extend the gear on climbout if you made a normal Vx departure. In order to avoid this happening with students, we would pull the breaker and reach down to hold the override switch to keep the gear up.

    Those breakers got worn out and broken off from all the pulling on the plastic button. That was simply part of doing business with that crappy system. Piper eventually developed an update kit to disable the system.

    As for the G1000, the only way to disable the LRU being simulated failed, is to pull its breaker. The cardboard template with the holes in it is a clever, low buck substitute, but it doesn't truly replicate the failure because some parts of the PFD are still operational with a partial failure. Knowing the reversionary mode of the PFD/MFD kinda makes it moot to dim the display.

    In other words, just pull the stupid breaker.
     
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  8. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    Yes. I got a good workout from my old CFII in the DA40/G1000 and found that with the displays both on but the AHRS breaker pulled, it was more difficult to fly than I expected. That's because the bank index is still on the display and that tended to make my brain want to believe I was flying level. I was having to scan past it constantly, going between the backup AI and the HSI on the G1000 which is the only Nav indicator.

    It was a valuable lesson, and one I never would have gotten by putting paper templates over the screen or just using manual reversionary mode.

    Amen.
     
  9. WannFly

    WannFly En-Route

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    There is a cardboard cutout available for G1000 that has the failures on them, you just put in front of the PFD . first time my CFI did that, I promptly hit the PFD/MFD switch button and he wasn’t amused .

    Not trying to derail the thread... but I think I might.... how do you do partial panel on a dual G5 and another vacuum driven AI on the same panel? The chances of all 3 of those failing is astronomical at best
     
  10. MauleSkinner

    MauleSkinner Final Approach

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    What are you defining as "partial panel"? The ACS doesn't use that term.
     
  11. PaulS

    PaulS Final Approach

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    The acceptable method of failure for a Perspective cirrus is to "fail" the MFD or PFD where the pilot puts it in reversionary mode. To your point, typically these airplanes are have dual pretty much everything that will automatically switch to the correctly functioning device. So pulling a circuit breaker for AHARS 1 will automatically switch it to Ahars 2, same for the ADC. Probably one of the most limiting failures would be the PFD or MFD going out, which is realistic, even that is pretty much a non event. You lose your moving map, checklists and a couple other things, no big deal.

    If you get a massive failure, both screens gone, then you have a backup AI, TC, Ball and airspeed below the panel. You are having a really bad day then, hopefully you have GP or FF running in your IPAD and can get to VMC . If not, you have that big red handle...….
     
    Last edited: Feb 15, 2019
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  12. WannFly

    WannFly En-Route

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    A situation where your AI fails and or some other instruments fail. Not sure what ACS calls it now
     
  13. WannFly

    WannFly En-Route

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    That’s the thing, I don’t know what to expect in a IFR checkride if DPE wants to do partial panel. In my case, let’s say he pulls the breaker for PFD, big deal, the other G5 will automatically switch. Comes with battery backup as well and if both goes belly up, there is a gyro AI with engine driven vacuum and backup vacuum. Oh well I don’t have to worry about checkride anytime soon considering I haven’t even taken the written yet
     
  14. MauleSkinner

    MauleSkinner Final Approach

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    I would imagine multiple unrelated instrument failures to be a non-starter for a checkride scenario, but if the examiner wants to see needle, ball, and airspeed & you’re so equipped, he could say “show me”.
     
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  15. PaulS

    PaulS Final Approach

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    I just had my checkride cancelled for weather, up again in two weeks. The failure is partial panel, which involves the dpe dimming either the pfd, most likely, or the mfd, less likely. Then you have to push the red button to get it into reversionary mode which gives you essentially a partial panel. This is what I have been told to expect and have practiced. I think there is some guidance from the FAA that I've seen, but I'm too lazy to look it up tonight.
     
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  16. N1120A

    N1120A Line Up and Wait

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    Seems to me that, if the breaker fails, partial panel on a G1000 is significantly easier than on a 6 Pack.

    On my instrument checkride, I flew a Dual G5 with a superfluous back up vacuum AI. The DPE failed both the G5s and I flew it that way. He could have failed the vacuum AI and I'd have still gotten it. In en route, hard IMC, AIs are vital. On a partial panel approach, your TC, GPS screen and altimeter/VSI are much more important.
     
  17. WannFly

    WannFly En-Route

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    i dont have TC anymore, so in checkride if DPE fails all 3 AI (2 G5 and the vacuum one).. i guess i will just have to tell him..its a very bad day and hope the right side is up
     
  18. flyingcheesehead

    flyingcheesehead Touchdown! Greaser!

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    Keep the compass as steady as you can, steer with just nudges of rudder and you'll probably still live.
     
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  19. Cici

    Cici Pre-takeoff checklist

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    Lazy question....Do the 172 G1000 birds come equipped like the Cirrus perspective/+? In other words, do they have dual bats, dual alternators, dual adahrs, dual flight computers etc that Cirrus has? Dual parachutes?
     
  20. asicer

    asicer En-Route

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    In a word, no. Cirrus is all electric and the 172 has vacuum powered standby.