Simulated Failures - G1000

Maddog1974

Maddog1974

Well-Known Member
So, the question has come up recently about whether or not we should use the circuit breakers to fail the G1000 PFD in our C-172's. We have the "G1000 guide for designated pilot examiners and certified flight instructors" handout/document, but right at the beginning of that document there is a paragraph that relates the following:

The system recommendations provided in this document are Garmin’s recommendations only and are superseded by the aircraft manufacturer’s recommendations and FAA-approved documentation for each aircraft model. The basic G1000 system architecture is similar across many aircraft models. However, the location of the actual components of the system, the location and grouping of the circuit breakers, and the engine instrumentation presentations vary between aircraft. Therefore, it is important to review the aircraft manufacturer documentation for each aircraft model.
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So, we also checked the POH for information on simulating a failure on the G1000 and there seems to be a lack there as well. We thought that we should fall back on the information provided in the G1000 guide but we are not sure. I pose the following questions to you:

  1. What does your flight school do for failures of G1000 primary systems/displays?
  2. Has anyone seen anything other than the guide I mentioned above concerning pulling the CB's to simulate a failure on the G1000?
  3. Do you have any other suggestions besides pulling CB's, dimming the screen, or stickers on screen?
Thanks in advance!
 
My flight school we either pop the breaker, or dim it down. There is a way to fail the airspeed, and altimeter, but I can not recall how at this moment.
 
Maddog1974 said:
So, the question has come up recently about whether or not we should use the circuit breakers to fail the G1000 PFD in our C-172's. We have the "G1000 guide for designated pilot examiners and certified flight instructors" handout/document, but right at the beginning of that document there is a paragraph that relates the following:

​
​
So, we also checked the POH for information on simulating a failure on the G1000 and there seems to be a lack there as well. We thought that we should fall back on the information provided in the G1000 guide but we are not sure. I pose the following questions to you:

  1. What does your flight school do for failures of G1000 primary systems/displays?
  2. Has anyone seen anything other than the guide I mentioned above concerning pulling the CB's to simulate a failure on the G1000?
  3. Do you have any other suggestions besides pulling CB's, dimming the screen, or stickers on screen?
Thanks in advance!
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Cessna has a document floating around that says "do not pull the circuit breakers, simulate failures by dimming the screen" but I can't remember if it's a regulatory (e.g. limitation) document, or advisory guidance. At my old school I think they simulate by either dimming or a paper cover. :-/

I don't remember if ADC and AHRS are on separate circuit breakers in the Nav 3 Cessna singles, but Garmin says—
*The simulated loss of AHRS and ADC cannot be accomplished individually in Cessna NAV III aircraft. In this case, the
applicant must simulate navigation on a desired course during en-route or approach operations by using the moving map
display. In order to determine more precisely the horizontal distance from the desired active leg, the applicant or the examiner
may select the cross-track (XTK) data bar field option on the MFD.
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Pull breakers, just don't reset them till you have the system completely shut down. I used to save my partial panel stuff till the end, pull breakers, shut down, and then put them back in.
 
Pull the breakers. It's good for the breakers to get exercised once in a while, otherwise as they age they get set and won't trip at the proper amperage. This is straight from an FAA study on aging airplane electrical systems, BTW. Go ahead and reset them in flight, that is exactly the same electrically as turning on the switch. I would suggest against doing it in IMC though, there is always that chance that the breaker won't reset. Oh, and I have no idea why Cessna decided to put the 2 most critical EFIS boxes (ADC and AHRS) on the same breaker. Terrible idea.
 
I dim the PFD. Circuit breakers aren't meant to be used as switches. This meets the requirements of the PTS and is better for the airplane.

The abnormal or emergency procedure for loss of the
electronic flight instrument display appropriate to the aircraft will be
evaluated in the Loss of Primary Instruments TASK. The loss of the
primary electronic flight instrument display must be tailored to failures
that would normally be encountered in the aircraft. If the aircraft is
capable, total failure of the electronic flight instrument display, or a
supporting component, with access only to the standby flight
instruments or backup display shall be evaluated
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mojo6911 said:
Circuit breakers aren't meant to be used as switches.
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You won't hurt anything pulling breakers. As I already posted, according to studies of old airplanes, exercising breakers actually makes them last longer. I wouldn't do it on every flight, but once in a while is not going to hurt anything.
 
You know those green, plastic, stick-on sun shades that they have for cars (and planes)? The DPE on my CFI-I checkride carried a double-layered one to cover the PFD. Works great and you don't have to fiddle around dimming the display or pulling CB's
 
Hey thanks for the replies from everyone. What we were looking for was something that might back that preference to not pull circuit breakers. One of the instructors tried the stick on type but after about half a dozen flights they were pretty useless. Dimming the screen is the option we have tried except that if you forget the position of the cursor or if the student, as they sometimes do, just starts pushing buttons and closes the menu, then you are screwed, time to kill the power to get a reset.

I was really looking for the any information from Cessna but google search hasn't turned up anything but the guide distributed by Garmin.

Ah well, post it notes seem to be the most economical and easiest way to kill it, guess we will stick with those.
 
Maddog1974 said:
Dimming the screen is the option we have tried except that if you forget the position of the cursor or if the student, as they sometimes do, just starts pushing buttons and closes the menu, then you are screwed, time to kill the power to get a reset.
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Just DIM the PFD. Once the student presses the red button and it goes into reversionary mode, you have access to the menu on the MFD, just as you did on the PFD.
 
Blackhawk said:
The aging aircraft study did say to reset circuit breakers during annuals, but it ALSO said NOT to use CBs as switches as this does the opposite- it puts too much wear and tear on CBs. Here is the Cliff Notes version.
http://www.aviationtoday.com/region...afe-Functioning-of-Circuit-Breakers_2043.html

This is one of those "a little knowledge being a dangerous thing" situations.
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Fair enough, I had not read that particular aging aircraft study. The ones I was familiar with were based on the PA31 and C402 series' of aircraft and didn't say anything about not using breakers as switches.

So now here is a question for you...
Would it be worthwhile for flight schools to replace G1000 circuit breakers with switch breakers of the same rating?
 
Just dim it! Works great. I fail to see why there is any other solution needed. It dims down to dark. For a reason. When done, use one of the (or *the* ) other displays to menu it back.
 
Roger Roger said:
Fair enough, I had not read that particular aging aircraft study. The ones I was familiar with were based on the PA31 and C402 series' of aircraft and didn't say anything about not using breakers as switches.

So now here is a question for you...
Would it be worthwhile for flight schools to replace G1000 circuit breakers with switch breakers of the same rating?
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Up to the school. They would need either an STC or field approval to do so. If they have a number of airplanes maybe it would be worthwhile.
 
Blackhawk said:
Up to the school. They would need either an STC or field approval to do so. If they have a number of airplanes maybe it would be worthwhile.
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Would it though? Electrically, a switch breaker is the same as a circuit breaker, so I doubt that would constitute a major alteration.
 
Roger Roger said:
Would it though? Electrically, a switch breaker is the same as a circuit breaker, so I doubt that would constitute a major alteration.
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Tell you what bud. Go ahead and install a switch in an aircraft that can be used to disable parts of the G1000 without an STC and see what the FAA has to say.
 
Blackhawk said:
Tell you what bud. Go ahead and install a switch in an aircraft that can be used to disable parts of the G1000 without an STC and see what the FAA has to say.
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You mean like a pullable circuit breaker? The mechanical action is different, but the function is exactly the same.

Have seen many aircraft with switch breakers in place of regular breakers for EFIS components. Don't know that an FAA inspector would have a legal leg to stand on. That doesn't mean they wouldn't throw a fit, but you know as well as I do that FAA inspectors throw fits about all kinds of things that are perfectly legal.

I also don't think anyone really cares enough to actually do it. Those who would want to, will probably just pull the circuit breaker and replace it for 20 bucks after 10k cycles or whatever when it stops latching, and those who care enough to not pull circuit breakers would worry themselves about putting in a switch breaker. It's an interesting thought though, at least to me.
 
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