|
Two 540s - redundancy question |
Post Reply 
|
| Author | ||
comancheguy 
Senior Member 
Joined: 24 Aug 2011 Location: Maryland Status: Offline Points: 160 |
 Post Options
 Thanks(0)
 Quote Reply
 Topic: Two 540s - redundancy questionPosted: 26 Jul 2015 at 4:32pm |
|
|
Noticed something on the way to OSH. Spoke to the guys in the booth, and wanted to document here.
I have two 540s. I wanted to "tune in a VOR" on the #2. Just to see what radial etc. from it. I push the OBS button on #2 and both of my 540s change to VOR from GPS. I can think of another case where this is "sub-optimal": If I were shooting an ILS, I might want to set #1 GPS, GPSS to the final, or vectors etc. I might want to put the ILS in the #2 540, so that I can see the analog cdi indications and notice that I have or do not have LOC/GS before and as the 540 auto switches. This, and the ensuing discussions brought up a few other points. Background: - My panel is wired, I believe, with the WX-500 and GDL-69 inputs going into the #1 540 and then shared between them. - My GPSS from my Stec-50 AP is wired only to #1. (My shop didn't like the idea of switching that input. - My shop sent my original 106A out to Garmin to be fixed, and installed a new one with the first 540. (530W replacement). My shop installed the fixed 106A with new 540 #2 install. I am not excited about the "single point of failure-ness" of all this. If my #1 box dies, I could lose a LOT of capability: AP/GPSS, XM and stormscope. I am not sure why I bought two 106As ($2500). Since, whatever I have one 540 tracking, the other is, too. I think that there should maybe be a software setting for the second box that says, "do what #1 is doing - or do your own thing" - I admit, that I don't know the whole perfect answer, yet. Any other thoughts on the way I'm wired, and general "no single Point of failure"-ness. I will say, so far... VERY Pleased with the 540s. "DISCUSS" :) Ken
Edited by AviJake - 27 Jul 2015 at 12:29pm |
||
 |
||
|
AviJake
Admin Group 
Joined: 26 Mar 2009 Location: Lincoln MA Status: Offline Points: 2815 |
Post Options
Thanks(0)
Quote Reply
Posted: 26 Jul 2015 at 5:17pm |
|
|
The first thing that sounds funky and not correct is pushing OBS on #2 should not change the nav mode on #1.
Very interested in getting those logs.
|
||
|
Steve Jacobson
sjacobson@avidyne.com |
||
|
||
|
teeth6
Senior Member
Joined: 10 Mar 2014 Status: Offline Points: 741 |
Post Options
Thanks(0)
Quote Reply
Posted: 26 Jul 2015 at 7:48pm |
|
|
Agree something is not right. I have 2 540s also. To change from GPS to VOR it is not a button push but rather a turn of the knob. I am definitely able to have my top 540 in GPS mode and my bottom 540 in VOR mode.
|
||
|
||
|
comancheguy
Senior Member
Joined: 24 Aug 2011 Location: Maryland Status: Offline Points: 160 |
Post Options
Thanks(0)
Quote Reply
Posted: 26 Jul 2015 at 10:11pm |
|
|
Hmmm... Maybe this is operator error. Standby...
|
||
|
||
|
DavidBunin
Senior Member
Joined: 20 May 2015 Location: Rockwall, TX Status: Offline Points: 742 |
Post Options
Thanks(0)
Quote Reply
Posted: 27 Jul 2015 at 10:06am |
|
|
When you push the knob, you toggle between GPS mode and OBS mode (but still in GPS navigation). I can see where this piece of data might be shared across units. When you rotate the knob, you toggle between GPS Navigation mode and VOR Navigation mode. I would not expect this to be shared across units.
|
||
|
||
|
comancheguy
Senior Member
Joined: 24 Aug 2011 Location: Maryland Status: Offline Points: 160 |
Post Options
Thanks(0)
Quote Reply
Posted: 27 Jul 2015 at 11:03am |
|
|
Thanks for the info. I recall trying twisting, pushing, etc... :)
But, ya know, when you are flying along, sometimes you're a bit distracted... Ken
|
||
|
||
|
AviJake
Admin Group
Joined: 26 Mar 2009 Location: Lincoln MA Status: Offline Points: 2815 |
Post Options
Thanks(0)
Quote Reply
Posted: 27 Jul 2015 at 11:06am |
|
|
No problem. Mind if I change the title of the thread? Would love to have it sound a little less serious to reflect the actual condition a little better.
I'll change it to "Two 540s - redundancy question" Edited by AviJake - 27 Jul 2015 at 12:30pm |
||
|
Steve Jacobson
sjacobson@avidyne.com |
||
|
||
|
comancheguy
Senior Member
Joined: 24 Aug 2011 Location: Maryland Status: Offline Points: 160 |
Post Options
Thanks(0)
Quote Reply
Posted: 27 Jul 2015 at 1:52pm |
|
|
Steve -
No problem on the title change. I don't want to be too harsh. :) Ken |
||
|
||
|
AviJake
Admin Group
Joined: 26 Mar 2009 Location: Lincoln MA Status: Offline Points: 2815 |
Post Options
Thanks(0)
Quote Reply
Posted: 27 Jul 2015 at 8:13pm |
|
|
My bad - I had to dope slap myself - wasn't thinking clearly about OBS. You can't have one IFD in leg mode (e.g. GPS or VLOC) and one in OBS mode if they are sharing a flight plan/guidance.
This is a consequence of there being just one FMS. If you want 2 FMS instances running, then CrossSync needs to be turned off. In OBS mode, there is a master (IFD #1) and a slave (IFD #2) for the OBS course. Since they are separate units, they can/will have separate CDIs. When you go into OBS mode on one, they both go into OBS mode. At that point, which selected course do you use? Answer = #1 IFD and we flag IFD #2 CDI as invalid because the selected course shown on CDI #2 has no bearing (pun intended) on the OBS course used in the IFD. Only CDI #1 is in use as the OBS source when in dual IFD with CrossSync and OBS mode active. There is a note to this effect in the OBS Mode part of Section 5 in the pilot guides: Note OBS Behavior in Dual IFD Operations For those installations that include dual IFDs t hat are separately wired to two different nav indicators, the #2 IFD will automatically switch into OBS mode when #1 IFD Nav Source has been put into OBS and the #2 nav indicator will flag invalid. This is because the FMS stays sync’d between the two IFDs. The #2 IFD will display the selected course as set by the #1 nav indicator on the map page. Sorry about the confusion I caused with the silly initial answer.
Edited by AviJake - 28 Jul 2015 at 7:51am |
||
|
Steve Jacobson
sjacobson@avidyne.com |
||
|
||
|
comancheguy
Senior Member
Joined: 24 Aug 2011 Location: Maryland Status: Offline Points: 160 |
Post Options
Thanks(0)
Quote Reply
Posted: 27 Jul 2015 at 10:00pm |
|
|
Now I am confused. I tried turning the obs knob, as suggested on #2 and it did, in fact, go to VLOC and #1 stayed in GPS. But, I had no Flight plan loaded, etc.
Looks like I'm gonna have to go flying again... :) AFTER I read the manual again. Ken Edited by comancheguy - 27 Jul 2015 at 10:01pm |
||
|
||
|
AviJake
Admin Group
Joined: 26 Mar 2009 Location: Lincoln MA Status: Offline Points: 2815 |
Post Options
Thanks(0)
Quote Reply
Posted: 27 Jul 2015 at 10:03pm |
|
|
That knob is the Nav Source knob. Twisting the knob toggles you between GPS and VLOC. In dual IFD installations you can put one IFD in GPS and the other in VLOC. When it is set to GPS and you press in the knob, it will push you into OBS mode.
|
||
|
Steve Jacobson
sjacobson@avidyne.com |
||
|
||
|
comancheguy
Senior Member
Joined: 24 Aug 2011 Location: Maryland Status: Offline Points: 160 |
Post Options
Thanks(0)
Quote Reply
Posted: 27 Jul 2015 at 10:05pm |
|
|
I think that is what I intended to do:
#1 - GPS #2 - VLOC - to tune a VOR or ILS. What is OBS mode? (I promise to read the manual). Ken
|
||
|
||
|
AviJake
Admin Group
Joined: 26 Mar 2009 Location: Lincoln MA Status: Offline Points: 2815 |
Post Options
Thanks(0)
Quote Reply
Posted: 27 Jul 2015 at 10:12pm |
|
|
There are folks who swear by this function but I'm personally no fan of it and never use it operationally. I'm sure some will speak up here and speak positively of the mode.
You use it to set a desired inbound or outbound course to/from a waypoint or fix or airport. Imagine trying to set up your own final approach into a private airfield that doesn't have a published approach. |
||
|
Steve Jacobson
sjacobson@avidyne.com |
||
|
||
|
teeth6
Senior Member
Joined: 10 Mar 2014 Status: Offline Points: 741 |
Post Options
Thanks(0)
Quote Reply
Posted: 27 Jul 2015 at 10:21pm |
|
|
The one benefit I like with OBS mode is to create a "runway extended line" when flying into an unfamiliar field. When I get close, I set the OBS to the runway heading and it creates that course to the field visually. Of course, once Avidyne incorporates an extended line in a release, that function won't be needed. 😉😉
|
||
|
||
|
brou0040
Senior Member
Joined: 13 Dec 2012 Location: KIYK Status: Offline Points: 720 |
Post Options
Thanks(0)
Quote Reply
Posted: 27 Jul 2015 at 11:21pm |
|
|
I'm sure I'm mixing up the exact details of what I did, but I was getting vectors all over the place a few days ago due to Airventure while IFR to eastern WI. I was told maintain heading XYZ and intercept QWE radial to waypoint ICantRemember. Anyways, I think I hit Direct To ICantRemember, put it into OBS mode, dialed in the QWE radial and flew XYZ until I hit the magenta line. If I remember correctly, ICantRemember was an intersection so putting it into VLOC would not have helped.
Unfortunately, my flight back to CA was cut short. A Cessna 340 that wasn't tied down jumped it's chocks and rolled right into my rudder. At least my 540 has been working!
Edited by brou0040 - 27 Jul 2015 at 11:23pm |
||
|
||
|
comancheguy
Senior Member
Joined: 24 Aug 2011 Location: Maryland Status: Offline Points: 160 |
Post Options
Thanks(0)
Quote Reply
Posted: 28 Jul 2015 at 10:16am |
|
|
So, I THINK that was I was trying to do, is possible. (tune a VOR on #2 while using GPS on #1.
That is good. Anyone have any comments on the lack of redundancy with all of the input/outputs going into #1? I was disappointed that I can't drive the STEC GPSS from either box. And that XM WX and Stormscope go into #1 and get shared. This is a philosophy thing. I apologize for the FUD around not understanding OBS mode. I'll dig into the manual. Ken |
||
|
||
|
LANCE
Senior Member
Joined: 06 Dec 2014 Location: TEXAS Status: Offline Points: 277 |
Post Options
Thanks(0)
Quote Reply
Posted: 28 Jul 2015 at 10:57am |
|
Not being able to switch from 1 to 2 on your autopilot and not having your weather on both boxes is laziness on your installer's part or not being willing to pay for the labor to do it. That can be done - has nothing to do with your Avidyne IFDs.
|
||
|
||
|
roltman
Senior Member
Joined: 04 Aug 2011 Status: Offline Points: 173 |
Post Options
Thanks(0)
Quote Reply
Posted: 28 Jul 2015 at 11:20am |
|
Steve, then I'm confused how you would do the following. Since I've been using OBS mode when doing the SID out of Memphis, how would you comply with taking off RWY 36R via the ELVIS3.EONEE? You'd get your initial vectors after takeoff then be told: "Fly 090, Join the departure" Based on what the IFD540 loads for waypoints for the SID and the fact you must join the 071 radial, what sequences would you use to get to EONEE? I can think of more or less 3 ways to do it: 1. Manually add the MEM VOR prior the EONEE fix then manually activate the leg and couple the AP to HDG with NAV armed in GPS. 2. Watch the bearing to the fix manually till it hits 071 then know to press -D-> to EONEE 3. Use the OBS mode on EONEE and twist 071 in the HSI and again leaving AP in HDG arm the NAV. Option #3 is IMHO the least button pushes, automated and it doesn't modify the flight plan, but you do get a flagged CDI on #2. Option #1 would work if you can insert waypoints in the SID and would result in both CDI's working, but seems cumbersome and results in changing the Flight Plan from what the unit loads for the SID. Option #2 results in eyes down watching numbers to time button presses. Or are you flying around using the IFD540 "HDG" mode that we all are waiting for? :) Which, by the way, I'm curious how that'll be rolled out given the current "push vs twist" functionality of the upper right knob. |
||
|
||
|
TogaDriver
Senior Member
Joined: 23 Sep 2013 Location: United States Status: Offline Points: 133 |
Post Options
Thanks(0)
Quote Reply
Posted: 28 Jul 2015 at 11:26am |
|
|
To clarify Lance's comment:
The STEC needs an ARINC 429 input from an IFD to enable GPSS steering. If you have two IFDs, you need a switch to select the ARINC input from either #1 or #2. I had this done for my 2 IFD installation and it works perfectly. On a side note, if you have an Aspen PFD installed and both IFDs already talk to it, you can simply use the Aspen's GPSS and NAV selection to achieve the same result via the STEC HDG mode. In my basic tests the Aspen GPSS and direct GPSS from the IFDs are equally effective. |
||
|
||
|
AviJake
Admin Group
Joined: 26 Mar 2009 Location: Lincoln MA Status: Offline Points: 2815 |
Post Options
Thanks(0)
Quote Reply
Posted: 28 Jul 2015 at 3:25pm |
|
I think we'd recommend Option 3. And for the duration that you have both units in OBS mode, you either turn CrossSync off (we don't recommend that) to get #2 CDI active, or know that it's flagged invalid.
|
||
|
Steve Jacobson
sjacobson@avidyne.com |
||
|
||
|
AviJake
Admin Group
Joined: 26 Mar 2009 Location: Lincoln MA Status: Offline Points: 2815 |
Post Options
Thanks(0)
Quote Reply
Posted: 28 Jul 2015 at 3:26pm |
|
|
Oh and the return of HDG mode to the Nav Source knob is not in the near future. We had a TON of cert hurdles on that.
|
||
|
Steve Jacobson
sjacobson@avidyne.com |
||
|
||
|
AviJake
Admin Group
Joined: 26 Mar 2009 Location: Lincoln MA Status: Offline Points: 2815 |
Post Options
Thanks(0)
Quote Reply
Posted: 28 Jul 2015 at 3:31pm |
|
Can't quite tell if this is understood from the post but to be clear, you have two options for wiring. Each 540 has 6 serial ports (5 usable if you have a dual IFD540 installation) which might be enough for most folks to wire an input (e.g. serial weather) into both IFDs. But for those that don't have enough ports for all their stuff or (understandably) don't want to spend the extra time/expense to add those wires, you can wire the input into one IFD and it is automatically shared with the other IFD across that CrossSync line. Both work equally as well. It's a personal tradeoff for the extra expense vs. the tiny chance that the crosssync wires between the two IFDs fail.
|
||
|
Steve Jacobson
sjacobson@avidyne.com |
||
|
||
|
comancheguy
Senior Member
Joined: 24 Aug 2011 Location: Maryland Status: Offline Points: 160 |
Post Options
Thanks(0)
Quote Reply
Posted: 28 Jul 2015 at 4:36pm |
|
|
Steve -
Or that ONE OF the IFD's fail (the one that everything is wired into). That is what worries me most. And one of the big reasons that I spent the $$$$ to install two of them. My shop chose to wire the inputs into box #1 and then let the IFD540's do the sharing. (I think). Ken |
||
|
||
|
AviJake
Admin Group
Joined: 26 Mar 2009 Location: Lincoln MA Status: Offline Points: 2815 |
Post Options
Thanks(0)
Quote Reply
Posted: 28 Jul 2015 at 4:54pm |
|
|
Of course. I just presumed the chances of an IFD failing is less than zero......
|
||
|
Steve Jacobson
sjacobson@avidyne.com |
||
|
||
|
comancheguy
Senior Member
Joined: 24 Aug 2011 Location: Maryland Status: Offline Points: 160 |
Post Options
Thanks(0)
Quote Reply
Posted: 28 Jul 2015 at 5:02pm |
|
Well, I talked to my shop, when we were planning the install, and they didn't want a switch to choose GPSS between #1 and #2. (Avidyne knows who my shop is, and they are supposedly on Avidyne's "good guy" list from what I gather. I don't want to bad mouth them. They aren't lazy and have a good rep and charge accordingly). If what Lance (and TogaDriver) are saying is true, that switching ARINC 429 is normally done and approved etc., then I may need to reopen this design issue with my shop. Same with wiring XM WX / Storm scope into both boxes. Now, having said this, the #1 box would have to die totally, or mostly, to not share data. But... Avidyne, can you confirm? I mostly sprung for the second 540, for the redundancy, and because my #2 nav/com was on it's last legs. Ken Edited by comancheguy - 28 Jul 2015 at 5:04pm |
||
|
||
|
Gring
Senior Member
Joined: 30 Dec 2011 Location: Kingston, NY Status: Offline Points: 720 |
Post Options
Thanks(0)
Quote Reply
Posted: 28 Jul 2015 at 5:21pm |
|
|
When my dual IFDs were installed, the traffic, weather, and lightning boxes were wired directly to both IFDs for the redundancy you mention. I would revisit the GPSS design with the shop as it isn't forging new ground. They've been doing #1 / #2 switches for NAV, DME, VOR, GPS, GPSS, etc. for many years and it isn't that complicated.
|
||
|
||
|
comancheguy
Senior Member
Joined: 24 Aug 2011 Location: Maryland Status: Offline Points: 160 |
Post Options
Thanks(0)
Quote Reply
Posted: 29 Jul 2015 at 10:59am |
|
|
His point about the GPSS was that it is a binary data format, not a voltage, like switching a VOR.
I agree that they are two different things. But, I don't know the proper answers. Ken
|
||
|
||
|
TogaDriver
Senior Member
Joined: 23 Sep 2013 Location: United States Status: Offline Points: 133 |
Post Options
Thanks(0)
Quote Reply
Posted: 29 Jul 2015 at 11:17am |
|
|
GPSS switching is simply a DPDT switch determining which ARINC 429 feed (2 wires) goes to the autopilot.
For ARINC 429: https://en.wikipedia.org/wiki/ARINC_429 For GPSS: http://www.avionicswest.net/articles/gpss.htm Hope this helps. Switching which IFD sends it's 429 to the autopilot is trivial.
Edited by TogaDriver - 29 Jul 2015 at 2:01pm |
||
|
||
|
AUXAIR
Senior Member
Joined: 01 Jul 2015 Location: KSUA Status: Offline Points: 138 |
Post Options
Thanks(0)
Quote Reply
Posted: 29 Jul 2015 at 1:56pm |
|
|
In an installation with dual IFD's - a 540 and 440, can the MLB 100 be wired to both units, or will it cause some confusion when/if they are in crosslink mode?
|
||
|
David E.
Cessna 182 RG II |
||
|
||
|
comancheguy
Senior Member
Joined: 24 Aug 2011 Location: Maryland Status: Offline Points: 160 |
Post Options
Thanks(0)
Quote Reply
Posted: 29 Jul 2015 at 2:10pm |
|
|
Thanks for the info.
|
||
|
||
|
AviJake
Admin Group
Joined: 26 Mar 2009 Location: Lincoln MA Status: Offline Points: 2815 |
Post Options
Thanks(0)
Quote Reply
Posted: 30 Jul 2015 at 7:41am |
|
MLB100 can definitely be wired to both without causing any confusion in CrossSync. |
||
|
Steve Jacobson
sjacobson@avidyne.com |
||
|
||
|
TogaDriver
Senior Member
Joined: 23 Sep 2013 Location: United States Status: Offline Points: 133 |
Post Options
Thanks(0)
Quote Reply
Posted: 30 Jul 2015 at 2:12pm |
|
|
Any timeline yet for ADS-B Traffic from an MLB100? I'm waiting to order mine until I see the feature in a release.
|
||
|
||
|
AUXAIR
Senior Member
Joined: 01 Jul 2015 Location: KSUA Status: Offline Points: 138 |
Post Options
Thanks(0)
Quote Reply
Posted: 31 Jul 2015 at 11:53am |
|
|
Thanks for that suggestion. Used the pseudo "Extended Center Line" via the OBS radial on my first flight with my new 540/440 and it worked excellently for an arrival at a strange field.
|
||
|
David E.
Cessna 182 RG II |
||
|
||
|
Post Reply
|
|
Tweet
|
| Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |
Topic Options
comancheguy wrote: