EricJ Posted May 1, 2018 Report Share Posted May 1, 2018 My installer is claiming that the STC for the IFD540 precludes it from having a second nav connected to the autopilot. In other words, they say my NAV1/NAV2 switch for my autopilot input must be deleted. I've looked in the online literature that I can find and can't find anything to support this claim. I'm skeptical about this for a number of reasons and don't want to lose the ability to drive the autopilot with NAV2 if I don't have to. Has anybody else had any experience with this? Another source that has done it said that the restriction may be valid if the other nav is also an Avidyne, but that's not the case for me. Quote Link to comment Share on other sites More sharing options...
1964-M20E Posted May 1, 2018 Report Share Posted May 1, 2018 I have the selector switch for GPS or NAV-2 in mine and it was there when the IFD540 was installed it is still there no questions asked about it. 1 Quote Link to comment Share on other sites More sharing options...
Marauder Posted May 1, 2018 Report Share Posted May 1, 2018 19 minutes ago, EricJ said: My installer is claiming that the STC for the IFD540 precludes it from having a second nav connected to the autopilot. In other words, they say my NAV1/NAV2 switch for my autopilot input must be deleted. I've looked in the online literature that I can find and can't find anything to support this claim. I'm skeptical about this for a number of reasons and don't want to lose the ability to drive the autopilot with NAV2 if I don't have to. Has anybody else had any experience with this? Another source that has done it said that the restriction may be valid if the other nav is also an Avidyne, but that's not the case for me. I would ask him to show you the specific verbiage from the installation manual that substantiates this claim. It I recall correctly, Avidyne created some conversation when it was asking buyers to sign some sort liability release document. Wonder if it is tied to this. 1 Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted May 1, 2018 Report Share Posted May 1, 2018 I just looked through the Avidyne 5XX and the Garmin 500 install manuals and I can't find anything that says anything about an autopilot switch. 1 Quote Link to comment Share on other sites More sharing options...
LANCECASPER Posted May 1, 2018 Report Share Posted May 1, 2018 2 hours ago, EricJ said: My installer is claiming that the STC for the IFD540 precludes it from having a second nav connected to the autopilot. In other words, they say my NAV1/NAV2 switch for my autopilot input must be deleted. I've looked in the online literature that I can find and can't find anything to support this claim. I'm skeptical about this for a number of reasons and don't want to lose the ability to drive the autopilot with NAV2 if I don't have to. Has anybody else had any experience with this? Another source that has done it said that the restriction may be valid if the other nav is also an Avidyne, but that's not the case for me. What gps are you replacing? Call Avidyne Tech Support in Melbourne FL - they'll be happy to talk to you. Quote Link to comment Share on other sites More sharing options...
EricJ Posted May 1, 2018 Author Report Share Posted May 1, 2018 Just now, LANCECASPER said: What gps are you replacing? New gps install plus a new audio panel and a G5 HSI. Previous stack was a KX170B and a TKM 170C. The TKM will stay as nav2/com2. They don't want to hook the TKM to the autopilot for reasons of which I am skeptical. The Century III autopilot previously had a NAV1/NAV2 switch, and they want to delete that so that only the IFD540 is connected to the autopilot. I want to retain the capability of driving the autopilot with NAV2. 1 Quote Link to comment Share on other sites More sharing options...
LANCECASPER Posted May 1, 2018 Report Share Posted May 1, 2018 5 minutes ago, EricJ said: New gps install plus a new audio panel and a G5 HSI. Previous stack was a KX170B and a TKM 170C. The TKM will stay as nav2/com2. They don't want to hook the TKM to the autopilot for reasons of which I am skeptical. The Century III autopilot previously had a NAV1/NAV2 switch, and they want to delete that so that only the IFD540 is connected to the autopilot. I want to retain the capability of driving the autopilot with NAV2. What are the reasons they are giving you that you are skeptical of? Quote Link to comment Share on other sites More sharing options...
carusoam Posted May 1, 2018 Report Share Posted May 1, 2018 Back in the day (90s) the switch was a requirement... it allowed two different boxes to supply guidance to the AP... VOR, ILS, and the independent GPS box. Today, one box has the internal switching to allow VOR, ILS, and GPS... If you have two, tri-talented boxes.... There isn’t a need to connect both to the AP.... But, There sure is a strong desire to be able to connect both... Review what your installer is saying... it might be the switch you have already can’t do the job? Getting a new switch is probably going to cost some part of an AMU? I always found this switch to be on the edge of an error waiting to happen in IMC. Switching from GPS to ILS for landing... If you go with a switch... have your procedures clear and useable with a back-up to know what source is being used... the last thing you want is to be following the wrong source without knowing it... approaching the ground... A little stress....That special blue light was easy to forget its meaning... blue light on, GPS was active source... Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
EricJ Posted May 1, 2018 Author Report Share Posted May 1, 2018 1 minute ago, LANCECASPER said: What are the reasons they are giving you that you are skeptical of? The IFD STC doesn't allow connection of a 2nd nav to the autopilot. Installation of a NAV1/NAV2 switch presents liability danger to the installer. Because... One of the managing technicians says he was on a flight where the crew flew an approach with the wrong nav selected and therefore he doesn't want to install a switch that makes that possible. Quote Link to comment Share on other sites More sharing options...
LANCECASPER Posted May 1, 2018 Report Share Posted May 1, 2018 Just thinking out loud, but I would think whether it is coupled to the autopilot or not, you would need some type of annunciation as to what nav source you were using near the CDI to make it safe and legal. For Nav 1 (Avidyne) it should tell you whether you are using GPS or VOR/LOC, and the same for NAV 2, since some Nav 2's will be a similar gps. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted May 1, 2018 Report Share Posted May 1, 2018 The danger is pretty clear... Accidently unknowingly following the wrong source... The possibility is pretty strong... like a GU landing... cognitive fatigue driven distractions... cognitive overload... The remedies are procedures and checklists... and a decent modern switch (anunciator) that is clear about the source... not just a blue light... somewhere on the panel... Then there is the concern of connecting some pretty old radio technology to your brand new digital tech... The switch needs to bridge... the two sources The display (HSI) the AP The Anunciator Our biggest electronic gremlins around here start with ‘did you clean the terminals’ As PIC, I would prefer to be able to make this decision myself, with my radio guy... If my radio guy balks, I would need a more knowledgeable radio guy... not one that knew a guy once..... I would expect a marketing/sales driven exclusion to come from Big G, not so much from Avidyne.... MS is a great place to go to ask these questions... PP thoughts only... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
bradp Posted May 1, 2018 Report Share Posted May 1, 2018 31 minutes ago, LANCECASPER said: Just thinking out loud, but I would think whether it is coupled to the autopilot or not, you would need some type of annunciation as to what nav source you were using near the CDI to make it safe and legal. For Nav 1 (Avidyne) it should tell you whether you are using GPS or VOR/LOC, and the same for NAV 2, since some Nav 2's will be a similar gps. My annunciator is a 1970's era rotary switch with an arrow that says "Autopilot Source" and can be rotated to Nav 1 or Nav 2. Kinda hard to miss. Quote Link to comment Share on other sites More sharing options...
carusoam Posted May 1, 2018 Report Share Posted May 1, 2018 25 minutes ago, EricJ said: ... One of the managing technicians says he was on a flight where the crew flew an approach with the wrong nav selected and therefore he doesn't want to install a switch that makes that possible. One of the MS pilots hand flew an approach once... probably yesterday.... Avoiding this is why we have GPSS connected with APs... Eliminating the switch to prevent a pilot error would be nice... but... The same elimination certainly adds to pilot work load when the primary nav box has failed... When the primary nav box has failed... is this the time to add to the work load, or just push the switch and make sure everything is working properly... This makes me think more... I like one very independent nav device... my nav2 with its independent VOR display is good like this. Frying that one big switch is going to take out a lot of nav capability... you kind of need a bachelors degree degree in computer skills to be able to review all the failure modes ... Make a list... if this fails... then use this.... If the list is 10 steps long before you get to the... use the iPad for primary nav... you have done well.... PP thoughts only... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
thinwing Posted May 1, 2018 Report Share Posted May 1, 2018 Seems simple...obtain the stc for the ifd540 and locate the statement.Also locate the stc for the autopilot itself.I have dual ifd install with g500 clearly identifying nav source to autopilot.In this case a single green indicator for Vor nav 1 and a double for vor nav 2.Similarly,gps Nav 1 is single magenta indicator.So there is no general proscription against dual Avidyne navy sources. Quote Link to comment Share on other sites More sharing options...
thinwing Posted May 1, 2018 Report Share Posted May 1, 2018 1 hour ago, N201MKTurbo said: I just looked through the Avidyne 5XX and the Garmin 500 install manuals and I can't find anything that says anything about an autopilot switch. That's because the g500 contains the switch 2 Quote Link to comment Share on other sites More sharing options...
Awful_Charlie Posted May 1, 2018 Report Share Posted May 1, 2018 I have a 540 and 440, and they are switched through the Aspen - works fine, and no questions about this from the installer 1 Quote Link to comment Share on other sites More sharing options...
pirate Posted May 1, 2018 Report Share Posted May 1, 2018 I have 540 and my auto pilot is connected to a switch. Nav 1 / Nav 2 Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted May 1, 2018 Report Share Posted May 1, 2018 1 hour ago, thinwing said: That's because the g500 contains the switch I was unclear about that. The Garmin manual I was reading was the install manual that covers the GNS530. Quote Link to comment Share on other sites More sharing options...
EricJ Posted May 2, 2018 Author Report Share Posted May 2, 2018 So today they clarified that their position is that because the Avidyne schematic does not show a switch between the unit and the autopilot, there cannot be one without them assuming liability for putting one there. I pointed out that at a minimum they should tell people that they will delete a very common item that was already installed sometime *before* their airplane is taken apart in their hangar. I'll try talking to Avidyne tech support about it. Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted May 2, 2018 Report Share Posted May 2, 2018 8 hours ago, EricJ said: So today they clarified that their position is that because the Avidyne schematic does not show a switch between the unit and the autopilot, there cannot be one without them assuming liability for putting one there. I pointed out that at a minimum they should tell people that they will delete a very common item that was already installed sometime *before* their airplane is taken apart in their hangar. I'll try talking to Avidyne tech support about it. The Avidyne schematic doesn't show a connection to a G5, how are they reconciling that? 1 Quote Link to comment Share on other sites More sharing options...
EricJ Posted May 2, 2018 Author Report Share Posted May 2, 2018 6 hours ago, N201MKTurbo said: The Avidyne schematic doesn't show a connection to a G5, how are they reconciling that? I suspect this is a case of somebody over-interpreting a document, but that's always a tough hurdle to get over. Quote Link to comment Share on other sites More sharing options...
thinwing Posted May 2, 2018 Report Share Posted May 2, 2018 It's a liability thing,I think there issue is with the TKM 170C...or more specifically the old tray and wiring (kx170)that it uses...they want to isolate it from ever driving the autopilot,having a wiring failure,causing an accident Quote Link to comment Share on other sites More sharing options...
EricJ Posted May 2, 2018 Author Report Share Posted May 2, 2018 2 hours ago, thinwing said: It's a liability thing,I think there issue is with the TKM 170C...or more specifically the old tray and wiring (kx170)that it uses...they want to isolate it from ever driving the autopilot,having a wiring failure,causing an accident I don't think so because all of that is getting rewired, anyway. They've not indicated that the TKM is the issue, just that the IFD installation manual doesn't specifically show a switch between the IFD and the Autopilot. Quote Link to comment Share on other sites More sharing options...
thinwing Posted May 3, 2018 Report Share Posted May 3, 2018 Hi there ,you think they will rewire entire connectors to kx170 tray?Do you now what that entails? Quote Link to comment Share on other sites More sharing options...
EricJ Posted May 3, 2018 Author Report Share Posted May 3, 2018 2 hours ago, thinwing said: Hi there ,you think they will rewire entire connectors to kx170 tray?Do you now what that entails? The avionics were entirely de-wired. Regardless, they've not cited the kx170 tray or existing wiring as having anything to do with the issue. Their liability worry is somebody having the switch in the wrong position, and it's a switch that doesn't appear in the IFD installation manual schematics. What's on the nav2 side of the switch doesn't matter to them. Quote Link to comment Share on other sites More sharing options...
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