Ask any successful military leader – no matter how well you can execute, a battle is generally won or lost in the planning stages. The same is true when planning an avionics upgrade (or initial installation for that matter, but that is a slightly larger topic), so I thought I’d share a little of the planning I am doing for a minor set of panel changes I have coming up. I estimate that the actual work will take a few days – the planning will, by the time I start, have consumed probably twice the number of hours. That’s a good ratio to think about when considering a project of this sort.
In this case, I am going to be upgrading my Grand Rapids EFIS system from a Single HX, Single HS, Single AHRS to a Dual HX, Dual AHRS system. Simply put, I will replace the single AHRS with a Dual, and the HS Display with an HX. The DU is ALMOST plug and Play (it would be if not for an internal GPS I have installed), and the AHRS requires a little additional serial (RS-232) wiring plus the installation of a second Magnetometer. Since I have the RAIM GPS module on the HS display, and it won’t plug in to the HX (without an external adapter), I’ll wire up my 696 as “GPS 2” for the overall system – been meaning to add that as an additional option anyway. In addition to this project, I am going to upgrade my Tru Trak Pictorial Pilot/Altrak to a Digitrak II VSGV. This means changing the control head and pitch servo, as well as removing the Altrak control box and push button/light. Since I have the Altrak controller in the back of the airplane near the servo, it means running some new servo wire all the way back behind the baggage compartment from the panel. Since adding the additional Magnetometer also means about six new conductors taking the same route, it makes sense to do the two upgrades at the same time. Since I’ll take the panel out to add the serial connections, that makes it super easy to do the additional autopilot wiring then as well.
That paragraph (above) is the culmination of the first part of the planning – figuring out the broad strokes of the project. I could do the two at different times, but that would require opening up the whole cabin and reclosing it twice. I could elect to do one or the other now, and only run additional wiring at this time, then hook up boxes later – but doing it at one time makes sense if I can afford it. I can do all the check-outs at once, and the airplane will be out of service less time. (Since the interior has to come out for the annual Condition Inspection now anyway – it’s a three-way winner!) Coming up with the conceptual plan for the upgrade involved requirements definitions, looking at what played well together, what was available, and what we could afford. It involved a little perusing of the manuals to understand the interconnections between the various boxes, and looking at such things as dimensions, panel layout issues (there aren’t any), and what to do with the empty hole where the Altrak button is now (still not sure, but I’ll come up with something…)
Armed with this overall plan, the next step was getting the hardware ordered and enroute – then once the reality had sunk in that equipment was on the way and work will actually begin in a short time, detailed planning was in order! One of the most awesome things about the modern experimental avionics market is the fact that almost everyone’s manuals are online. That gives me instant access to wiring diagrams, wire lists, pin numbers – and better than all that, installation plans for various avionics combinations. I salute all the manufacturers who recognize that their equipment is going to be used with the equipment from other manufacturers to build a system, and have already developed detailed drawings for how an installer can set things up to make them work. In my case, GRT and Tru Trak have drawings that show how to hook up exactly the system I am building with the Garmin 430 that I have had in the airplane all along. Since I already have the wiring drawings for the system as it is installed today, it was simply a matter of looking at the changes between the two configurations and building a DETAILED list of new interconnects that I have to make.
Note the emphasis on the word DETAILED. That is the key. Long before I pull the panel apart, or even open the boxes as they arrive, I should know, wire for wire, what I need to do to achieve a given configuration. Without this knowledge, you’ll find yourself working in the blind, stumbling along at the workbench until you figure out that you don’t have enough D-Sub pins, or that Male 9-pin shell you thought you had has disappeared (oh yeah, you used it on another project months ago!). Planning includes getting ALL the resources lined up – including wire stock, heat shrink, back shells, cable clamps – everything that you need to install the project without having to stop and order something. Only by developing a detailed plan can you anticipate these needs.
In this case, here is how I documented the work needed for this project. I simply built a “wire change” list That starts like this:
Dual AHRS Install
Wire AHRS 2 to DU 1:
DU 1 Connector A - Pin 24 to AHRS 2 Pin 03 (AHRS 2 Input to DU1 - Serial 6)
Wire AHRS 2 to DU 2:
DU 2 Connector A – Pin 4 to AHRS 2 Pin 05 (DU Output to AHRS 2 – Serial 4)
DU 2 Connector A – Pin 19 to AHRS 2 Pin 01 ( AHRS 2 Input to DU 2 – Serial 2)
Wire AHRS 2 to Mag 2:
AHRS 2 Pin 7 – Mag 2 Pin 2 (Z)
AHRS 2 Pin 8 – Mag 2 Pin 1 (Y)
AHRS 2 Pin 9 – Mag 2 Pin 3 (X)
AHRS 2 Pin 14 – Mag 2 Pin 5 (GND)
AHRS 2 Pin 18 – Mag 2 Pin 6 (CNTL)
AHRS 2 Pin 22 – Mag 2 Pin 4 (Power)
[And So on.....]
I build this list for each and every connection that has to be made or changed, researching the contents by looking in the manuals and drawings. Identifying connector and pin numbers at your desk and writing them all down will pay off when you get in the shop – you’re less likely to make a mistake if you have done your research and checked the work over. Doing this detailed review will ensure that what you plan is actually feasible, and will identify any “gotcha’s” in your plan. In addition to this wiring list, you can do just as detailed list of the wires that need to be dragged through the fuselage, and where they have to go.
There are several other things you can put in to your “pre-battle-plan”. Will you need hardware for mounting anything? Raw material for fabricating brackets? Are there drawings out there that will allow you to pre-fab the brackets? Will you need to upgrade or add circuit protection? How about cooling? Once you get that UPS shipping notice, the clock is ticking – and you can’t play with the new toys until they are fully installed, so get to work early and be ready to storm the castle!
Paul
In this case, I am going to be upgrading my Grand Rapids EFIS system from a Single HX, Single HS, Single AHRS to a Dual HX, Dual AHRS system. Simply put, I will replace the single AHRS with a Dual, and the HS Display with an HX. The DU is ALMOST plug and Play (it would be if not for an internal GPS I have installed), and the AHRS requires a little additional serial (RS-232) wiring plus the installation of a second Magnetometer. Since I have the RAIM GPS module on the HS display, and it won’t plug in to the HX (without an external adapter), I’ll wire up my 696 as “GPS 2” for the overall system – been meaning to add that as an additional option anyway. In addition to this project, I am going to upgrade my Tru Trak Pictorial Pilot/Altrak to a Digitrak II VSGV. This means changing the control head and pitch servo, as well as removing the Altrak control box and push button/light. Since I have the Altrak controller in the back of the airplane near the servo, it means running some new servo wire all the way back behind the baggage compartment from the panel. Since adding the additional Magnetometer also means about six new conductors taking the same route, it makes sense to do the two upgrades at the same time. Since I’ll take the panel out to add the serial connections, that makes it super easy to do the additional autopilot wiring then as well.
That paragraph (above) is the culmination of the first part of the planning – figuring out the broad strokes of the project. I could do the two at different times, but that would require opening up the whole cabin and reclosing it twice. I could elect to do one or the other now, and only run additional wiring at this time, then hook up boxes later – but doing it at one time makes sense if I can afford it. I can do all the check-outs at once, and the airplane will be out of service less time. (Since the interior has to come out for the annual Condition Inspection now anyway – it’s a three-way winner!) Coming up with the conceptual plan for the upgrade involved requirements definitions, looking at what played well together, what was available, and what we could afford. It involved a little perusing of the manuals to understand the interconnections between the various boxes, and looking at such things as dimensions, panel layout issues (there aren’t any), and what to do with the empty hole where the Altrak button is now (still not sure, but I’ll come up with something…)
Armed with this overall plan, the next step was getting the hardware ordered and enroute – then once the reality had sunk in that equipment was on the way and work will actually begin in a short time, detailed planning was in order! One of the most awesome things about the modern experimental avionics market is the fact that almost everyone’s manuals are online. That gives me instant access to wiring diagrams, wire lists, pin numbers – and better than all that, installation plans for various avionics combinations. I salute all the manufacturers who recognize that their equipment is going to be used with the equipment from other manufacturers to build a system, and have already developed detailed drawings for how an installer can set things up to make them work. In my case, GRT and Tru Trak have drawings that show how to hook up exactly the system I am building with the Garmin 430 that I have had in the airplane all along. Since I already have the wiring drawings for the system as it is installed today, it was simply a matter of looking at the changes between the two configurations and building a DETAILED list of new interconnects that I have to make.
Note the emphasis on the word DETAILED. That is the key. Long before I pull the panel apart, or even open the boxes as they arrive, I should know, wire for wire, what I need to do to achieve a given configuration. Without this knowledge, you’ll find yourself working in the blind, stumbling along at the workbench until you figure out that you don’t have enough D-Sub pins, or that Male 9-pin shell you thought you had has disappeared (oh yeah, you used it on another project months ago!). Planning includes getting ALL the resources lined up – including wire stock, heat shrink, back shells, cable clamps – everything that you need to install the project without having to stop and order something. Only by developing a detailed plan can you anticipate these needs.
In this case, here is how I documented the work needed for this project. I simply built a “wire change” list That starts like this:
Dual AHRS Install
Wire AHRS 2 to DU 1:
DU 1 Connector A - Pin 24 to AHRS 2 Pin 03 (AHRS 2 Input to DU1 - Serial 6)
Wire AHRS 2 to DU 2:
DU 2 Connector A – Pin 4 to AHRS 2 Pin 05 (DU Output to AHRS 2 – Serial 4)
DU 2 Connector A – Pin 19 to AHRS 2 Pin 01 ( AHRS 2 Input to DU 2 – Serial 2)
Wire AHRS 2 to Mag 2:
AHRS 2 Pin 7 – Mag 2 Pin 2 (Z)
AHRS 2 Pin 8 – Mag 2 Pin 1 (Y)
AHRS 2 Pin 9 – Mag 2 Pin 3 (X)
AHRS 2 Pin 14 – Mag 2 Pin 5 (GND)
AHRS 2 Pin 18 – Mag 2 Pin 6 (CNTL)
AHRS 2 Pin 22 – Mag 2 Pin 4 (Power)
[And So on.....]
I build this list for each and every connection that has to be made or changed, researching the contents by looking in the manuals and drawings. Identifying connector and pin numbers at your desk and writing them all down will pay off when you get in the shop – you’re less likely to make a mistake if you have done your research and checked the work over. Doing this detailed review will ensure that what you plan is actually feasible, and will identify any “gotcha’s” in your plan. In addition to this wiring list, you can do just as detailed list of the wires that need to be dragged through the fuselage, and where they have to go.
There are several other things you can put in to your “pre-battle-plan”. Will you need hardware for mounting anything? Raw material for fabricating brackets? Are there drawings out there that will allow you to pre-fab the brackets? Will you need to upgrade or add circuit protection? How about cooling? Once you get that UPS shipping notice, the clock is ticking – and you can’t play with the new toys until they are fully installed, so get to work early and be ready to storm the castle!
Paul
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