NicoN

To be honest, the installation of our GI275s was not "flawlessly". First, the installer could not go through the calibration process for the GMU11. We could solve this problem, but then the A/P did not react to the heading bug as expected. It turned out, that the C21 flight controller was still jumpered for using a DG, but the GI275 "talks" HSI. It was not easy to convince the installer of what ist wrong, but finally it worked. Our C21 was working absolutely fine before the GI275-move, but is still not completely fine. 1. NAV/APPR mode is always working ( a little of center, but working) 2. HDG mode is always while the A/C is in the hangar. 3. Sometimes HDG mode stops working while in flight or while taxiing. In the air, the A/C is simply flying straight and wings level, like a wing leveller not reacting on the HDG bug. 4. Sometimes the function comes back shortly after landing. 5. It seems to be related to temperature. On real hot days it did not work. Last weekend I did several flight each 2h and it worked perfect. My first suspicion was a faulty connection from GI 275 (heading error) to the C21 flight controller. I followed the signal from the connector Pin 17 to the upmost PCB (it is a stack of 3 PCBs and soldered a little cable to measure the signal. If anything works, I can measure a voltage of 0... 9,7V, depending on the position of the heading bug (max to the left is 9.7V, max right almost 0V, or vice versa). in the middle position the voltage is around 4.8V (half of 9.6V). So, exactly as you posted it. If the HDG mode stops working, I measure 4,77V on this Pin 17 and it does not change with moving the heading bug. Of course, this can be a phantom voltage which does not come from GI275, but from the flight controller itself. So, the faulty connection is not completely ruled out. I was lucky, to buy a C21 flight controller for almost nothing on ebay, which is only partially working. The C21 Flight controller has 3 stacked PCB which are folded and connected with ribbon cable. The upper 2 can be easily removed while the bottom one is together with the front panel and the housing - so i call it the "chassis" - Our flight controller was bench checked as fully working - i was not possible to "provoke" the failure with a heater in the footwell - the misbehaviour happens also if I change the upper 2 stacked PCBs to the ebay chassis. So, a problem can still be on the upper 2 PCBs @Jake@BevanAviation: Can you give me additional information about that "routing" IC? All the ICs are thru-hole chips which are availbale via digikey, but there are many chips to change. So, a lot of work. Most of the chips are 4xAND, NAND, OR, NOR chips. Still, I am not sure that the GI275 is NOT the reason. At least, I can confirm that the HSI becomes not more than handwarm. Is the PFD with ADHARS-AP running hot? I am also not sure, that the AP HEADING ERROR LO signal is connected correctly.

A couple of days ago, I was forwarded a beechtalk newsletter, where on topic is something about GI 275s and Century A/P The beechtalk.com website is not available at the moment. I was pretty electrified , that there was information about problems with GI275s an some Century A/P, e.g. the 21 model which we have. Since the GI 275 was installed we have intermittent trouble but only with the HDG-mode. Everything else is working fine (more or less). It seems that especially under high temperatures, the A/P stop reacting on changes on the heading bug. The A/C then simply flies straight on the last heading (of course starts deviating). It is a wing leveler only then. Sometimes the HDG mode comes back by opening the ventilation air. Sometimes you can kill this function by switching on cabin heat. In the failure case, I can measure a voltage of 4.77V on the heaidng error signal inside the A/P controller! The beechtalk newsletter says something to install a 1kOhm resistor to improve impedance and avoid "power fault " messages. For our C21 this is even warranty reimbursed! To be honest: I have never seen this message, but I am pretty interested to see WHERE this resistor is installed. I am afraid, the newsletter does not giv any information about that! I do not even find a SB about that, rather than an installation manual with the necessary information. Has anyone additional information ?

In the meantime my partner analysed our JPI data and is of the opinion that in September 2023 the spread increased. I think a couple of month we had 2 cylinders replaced. At least one is in the group of leanest/ richest.

Recently, my co-owner found a GAMI-spread of 1,0 ..1,2 gallons between leanest and richest cylinder 2 and 4. Our A/P cleaned the nozzles with ultrasound and MEK, but teh result is noo change. What to do in this case? Swap nozzles 2 and 4? BTW: my co-owners says not to fly LOP. Is our GAMI-Spread really too high?

Yes, I have it

Thank you! I am also of the opinion that it is not a general problem. 1. HSI can work as a PFD, I checked the auto-revert feature a couple of months ago - IAS and altitude are the same and headings is also fine 2. you can see that the msic. Field CAN indicate the winds aloft. Nevertheless there are rumours that in general the winds aloft calculation might confuse left and right Garmin was not interested in my video but recommended to find a solution with my authorized Garmin dealer. To be honest: my "authorized Garmin dealer" was not able to complete the calibration of the GMU11. They did not even have a secret contact to a Garmin guru to find the solution We are definitely not on the latest firmware (we have 2.62). Wasn't there something that the latest firmware makes my analog NAV2 (KX155) useless? I was hoping that someone says "this problem is solved with FW xyz" or a sophisticated config value

Video to demonstrate th eproblem As you can see, I have winds aloft indication on the PFD and also TAS. The problem for the HSI is also shown

Sorry, my posting was not precise. English is not my native language. And yes - we have OAT, we see as calculated TAS on PFD; that works The Misc. Field on the PFD can display winds aloft in different flavors, such as Headwind/crosswind, windspeed and a little arrow for direction and also windspeed and driection in degress. All work fine on the PFD Same can be configured on the HSI and this time the indication of valid information does not start automatically, but only afetr appling the setting again. then I see the information I want. On top, the setting seems to be volatile; with the next flight the same problem arises - definitely not a real problem but annoying.

GI275 has an option to display a "Misc. Field" in the display of a PFD and also on the HSI. one option is to display wind/velocity in different versions I configured the HSI to display wind direction and velocity. Therefore a little block appears on the display with "360/--"; sounds fine. The aircraft is on ground, so no GPS-Speed or track and also no airspeed. But, while in the air, it did not display the wanted information - still "360/--". Then - while - flying, i configured the same setting again, and voila, now it displayed a value (no clue if correct). on my next flight - same problem again, information is displayed but non-sense. And again, problem can be solved by applying the setting again. Any ideas ? is this a known problem? i did not see that this is addressed by a higher firmware (we have 2.62)

Our A/P wants to overhaul our alternator and/or the slip clutch (?) I saw once in januaray a fluctuatiing indication of our amperemeter (rapidly moving hand, but only about 10% of the meter range). This stopped after a couple of minutes and I have never seen it again.

We have this little panel with 4 fuses in the copilots foot well. One is for instrument lighting. On top there is a C/B for the same purpose. Why?

I was asked from my partner if we (also) have an additional screen filter besides the normal oil filter. The reason for the question: In a PIPER owned by his son horrible things were found in the screen filter

I started this topic a long time ago. I simply noticed that your CDT needle did not move at all A shop diagnosed the indicator as faulty, but it was never changed. Trying to find out what to do, I simply disconnected the sensor and measured the resistance: overload. Then I shortened the wires to the instrument with master switch on - full deflection. So instrument is fine. we then replaced the sensor and CDT is working since then. My experience: during takeoff, at sea level CDT was never an issue. The needle is moving a little but never critical. The higher I climb, the more CDT is rising. I saw situation where I had to lower the power as CDT was approaching the limit temperature.

Right, we also have electrical trim but not auto-trim. So, the answer is: we need THREE servos Next question: We have 2 GI275 installed; do we ONLY need Servos (3) and a mode controller, or do we need another G5 or GI275?

I Recently changed the setting for the MISC.Field on the PFD and the HSI The PFD shows now a direction arrow and wind speed. On the HSI , I configured this MISC Field to indicate Headwind/crosswind, but this shows only two lines of dashes (in the air) The previous setting was TAS and it worked. So, I think the HSI has all necessary information it needs What is worng?