Do I need/should I go to an avionics shop?

Discussion in 'Avionics and Upgrades' started by Sluggo63, Jan 2, 2021.

  1. Sluggo63

    Sluggo63 Cleared for Takeoff

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    Sorry if this is a basic question. New owner here looking to install an engine analyzer in my panel (Seneca III). Is this something any A&P can do, or should I be looking at a "dedicated" avionics shop.

    Also thinking while they have the panel apart, having some old stuff removed (LORAN, ADF, etc.). Same question as above.

    TIA
     
  2. WannFly

    WannFly Final Approach PoA Supporter

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    My engine analyzer was installed by AP/IA. The connection to GPS is something he didn’t want to touch but ran the wires.

    Don’t know about removing other avionics
     
  3. Bell206

    Bell206 Final Approach

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    Depends on the APIA. Some prefer not to get involved in the more complex analyzers. But if your APIA elects to install it perhaps turn into an owner-assist job if their willing? Outside certain test/check/dealer requirements an APIA can install/sign off a wide range of equipment.
    Same as above, depends on the APIA. If it's only a removal I've found most mechanics will take it on provided they don't mind messing with wires.
     
  4. Dana

    Dana En-Route

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    An A&P can do it, but a lot of A&P's aren't particularly good with electrical stuff.
     
  5. Tom-D

    Tom-D Taxi to Parking

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    It is a case if when the smoke gets out, who is going to replace it.
     
  6. kshaw

    kshaw Pre-takeoff checklist

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    My IA did the entire installation for me. He is good with avionics installations.
     
  7. Sluggo63

    Sluggo63 Cleared for Takeoff

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    Thanks, all. It sounds like it might be best to go to an avionics shop for all this.
     
  8. TommyG

    TommyG Pattern Altitude

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    Me and my buddy who is an A&P did ours in our 182. It was a lot of work that was tedious. Took about 40 hours, all except for linking it up to the Garmin 530.
     
  9. WannFly

    WannFly Final Approach PoA Supporter

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    Bw I am not sure avionics shop would be willing to drill holes for the EGT probes or play with the fuel sender. My avionics shop is next to the APIA, anything firewall forward, they refer to the APIA. Check with the shop first.
     
  10. JOhnH

    JOhnH Touchdown! Greaser!

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    My A&P did a good job with my EDM 700, but I think I'll take it to an avionics shop when upgrade it to an EDM 900/930. Largely because, like you, "while I'm in there I might as well . . ." I'll probably do a full panel upgrade.
     
  11. Wagondriver

    Wagondriver Pre-takeoff checklist

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    I did my own, and one other. And I hate electrical stuff, they aren’t very hard to do. If in doubt, follow the instructions!
     
  12. David Megginson

    David Megginson Pattern Altitude

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    You're going to get a lot of answers. I'm not going to try to claim any general truths, but just relate my own experience.

    For my intercom in 2002, my Stormscope in 2005, my autopilot in 2011, and my IFR GPS in 2017, I chose a major, reputable avionics shop every time (the kind that works on higher-end aircraft, like turbines, as well as our little pistons). Their hourly rate is usually a bit higher than a general-purpose shop — maybe $25/hour higher or more — and there's a bit more of a wait to get in, but to offset that, there were huge advantages:
    • They do these installations all the time, so I wasn't paying them extra hours for on-the-job training.
    • They did it right.
    • They stood behind their work.
    • They finished the work quickly, so I was without my plane for only about a week in each case.
    • They finished when they said they would.
    • They finished within their cost estimate.
    Many people (not everyone) who go shopping for the lowest quot. end up having things go badly wrong on at least one of these points.
     
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  13. Domenick

    Domenick Line Up and Wait

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    It depends on the engine analyzer. I installed a simple 4-cyl CHT only unit (AeroSpace Logic) under supervision. I'm pretty sure I could have handled a CHT/EGT unit, but beyond that, I would have gotten help.
     
  14. bnt83

    bnt83 Final Approach

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    Engine monitors

    A&P IAs can do them, but I would certainly consult them about it.

    Primary concerns off top of my head;

    Do they have the tooling to do it? Do they have D-Sub contact crimper to install GPS data interfaces? What about contact extractors?

    Do they have the knowledge and tools to complete simple sheet metal projects, making adapter plates and brackets as needed?

    Do they have have tools to crimp heavy gauge cables like 8 gauge and bigger if locating and installing shunts?

    Does the airplane already have enough breakers to add needed busing per the STC? If not, do they have the skill and knowledge to fabricate and install bus bars and add breakers?

    Does this install require a compass swing?

    Do they have knowledge and experience to complete an electrical load analysis?

    Will this install be interfacing legacy fuel quantity transmitters? If so, do the existing transmitters work well enough to be interfaced to a digital instrument? If unknown, is there enough budgeted to replace the fuel quantity transmitters?

    Will this be interfaced to a legacy instrument lighting dimmer?

    Obviously there needs to be a log entry, 337, equipment list revision, weight and balance revision and any airplane flight manual supplements provided.
     
    Last edited: Jan 4, 2021
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  15. murphey

    murphey Touchdown! Greaser! PoA Supporter

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    For the engine analyzer, there's not much needed in the panel other than connecting the wiring to the display in the panel. If it's a JPI or EI, the wiring diagram comes along with the gear and display. On the JPI they are DB9 and DB15. If Radio Shack were still around, you could go there and get the plugs.
    If an A&P is unwilling to install an analyzer, I'd really wonder about the A&Ps qualifications. As for removing old stuff, again, it's removing the displays, removing the wiring from the antennas (which should be removed, too), and removing the wiring to the electrical system. Wouldn't hurt to have the airplane weighed after all this is done. When I had 40 yr old wiring and gear removed, I gained 10 pounds of load!

    I hung out at the shop while they were installing the JPI - punch holes and install the probes. GPS isn't required for analyzer, but is an add-on. If you don't have a GPS, no need for that wiring.

    Here's the back of the JPI 730 - standard connectors.

    upload_2021-1-4_9-35-51.png

    Here's the EGT probe and the CHT probe :
    upload_2021-1-4_9-38-47.png upload_2021-1-4_9-39-16.png


    If the A&P doesn't understand how to take the end of the CHT or EGT cable, get the correct connector (DB9 or DB15 on the JPI) and crimp the wire into the connector, they should go back and take General again. This is all stuff taught in A&P school, nothing out of the ordinary. But that's my opinion.
     

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  16. David Megginson

    David Megginson Pattern Altitude

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    Not being an A&P (avionics or otherwise), I'm still curious about the original questions:

    How do decide if that specific installation requires a new compass swing?
    Do they know enough to avoid overloading the bus?
    Do they know how to do an electrical-load analysis after installing?

    etc.
     
  17. murphey

    murphey Touchdown! Greaser! PoA Supporter

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    FAR 23.1327
    AC 43.13-1B lists several instances when a compass swing must be performed. These include:

    • Whenever the accuracy of the compass is suspected
    • After a cockpit modification or major replacement involving ferrous metal
    • Whenever a compass has been subjected to a shock; for example, after a hard landing or turbulence
    • After aircraft has passed through a severe electrical storm
    • After a lightning strike
    • Whenever a change is made to the electrical system
    • Whenever a change of cargo is likely to affect the compass
    • After an aircraft has been parked on one heading for more than a year
    • When flux valves are replaced. (No clue what these are)

    So, the answer depends on where the analyzer display is installed, which indicates where the wiring is located, and if any of it is affecting the compass. When I had the JPI 730 installed, the display was below everything, next to the tach, so the A&P/IA decided it did not affect the compass on top of the glareshield.

    Best way to find out - turn everything on. If the headings match what's on the correction card, then the analyzer display is not affecting the compass so no need for a new compass swing.

     
  18. Bell206

    Bell206 Final Approach

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    FYI: Depends. Some APs turn down work based on the type of work. I used to handle the oddball installs (Analyzers, avionics, etc.) other APs would pass on as it wasn't as profitable to them to perform that type work. But yes there are some APs who have never done electrical type work and prefer not to do electrical work but it's hardly a "qualification" issue.
     
  19. murphey

    murphey Touchdown! Greaser! PoA Supporter

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    I put this in the qualification category because they're supposed to know this stuff. I agree that many don't want to do it, but the FAA has declared them qualified when they passed the A&P exams - written and practical.
     
  20. Bell206

    Bell206 Final Approach

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    If the installation documents do not reference or answer those questions then the answers are in various FAA mx reference docs. As with any alteration it falls to the installer to know and follow the correct references and guidance. But if you're curious to those actual answers it would be specific to the equipment installed.
     
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  21. Power cat

    Power cat Pre-Flight

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    Stop making sense
     
  22. murphey

    murphey Touchdown! Greaser! PoA Supporter

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    Forgive me! I don't know what I was thinking....I'm just not in the right mindset to write more python code to translate silly parameters into binary values usable by a C++ program.
     
  23. Bell206

    Bell206 Final Approach

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    You do realize engine analyzers are not part of the A&P curriculum? Rather they fall under the catch all performance rule in Part 43.13 after an A&P receives their certificate just as the 99.9% of all the other work an AP might perform. There are technically no "qualifications" for an A&P only basic knowledge/experience/skill requirements and per Part 65 in order for an A&P to exercise their privileges, like install an engine analyzer system for the 1st time, they must meet certain minimums to legally perform the work. It is what it is.
     
  24. bnt83

    bnt83 Final Approach

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    Just a few things considered on my last one,

    Sheet metal bracket needed to mount the ammeter shunt, Simple enough how I did it. This airplane had the OEM shunt built into the OEM engine instrument cluster and my chosen location of the new shunt required fabrication of replacement 8 gauge cables to connect the bus to the shunt.

    Mounting the engine data converter required fabricating and installing a plate that adapted an existing previously removed vacuum air filter assembly location to mount the data converter.

    Connecting the engine monitor to the GPS required removal of the entire avionics stack for reasonable access the Garmin GTN connectors behind the panel. Since this aircraft already had an array of RS-232 connections I rang out all the wires and made a diagram that recorded how it was already wired so I could plan how the monitor was going to be added.

    Manifold pressure sensor required fabricating a simple hat shape bracket and riveted to the firewall.

    The original oil pressure sense hose was about 4 feet long and wrapped all the around the engine from LH front of the engine to the RH upper firewall. That hose was removed and a new 18" teflon hose with a straight fitting was ordered. After fighting with the straight fitting connection to the engine I order another hose with a 45 degree fitting. The oil pressure sensor needed another bracket which I made from adels, using two adels around the steel engine mount tubes and by flattening one adel strap to connect them, drilling a few holes in the straps and mounting the sensor.

    With the OEM engine instrument cluster now removed I had a pretty large hole to fill, more sheet metal.

    The engine monitor display resides in an a factory cut VOR hole which only has three screw holes, so I made a plate and filler to lay over that and capture all 4 screws for the display.

    Then there is the fuel quantity system, wiring, draining the fuel tanks, leveling the airplane and adding fuel while going through the calibration process. The old floats in the tanks were shot so this went swimmingly after giving up and ordering new ones.

    EGT/CHT probes harness bundling, routing & mounting.

    The OP's Seneca is a twin so take some that work times 2.
     
    Last edited: Jan 4, 2021
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  25. MooneyDriver78

    MooneyDriver78 En-Route

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    There are special concerns that an inexperienced AP may not know, I’ve seen some bad installations of an EM.

    2 common mistakes:
    The FF sensor should be horizontal and no 90° bends near the end for accuracy, and protected from heat of the engine.
    The EGT/CHT thermocouples are sensitive to induced currents from other electric wires (spark plug wires), do not cable tie them together, keep them apart, like ignition wires on the inside of the pipes and EM wires on the outside.

    Also, sometimes you’ll need to add a snubber to the MP sensor to smooth it out.
     
  26. Martin Pauly

    Martin Pauly Line Up and Wait PoA Supporter

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    Really depends on the A&P. Some are good at electrical stuff, and others aren't. An engine analyzer installation is a large job, but not a very difficult one. Compared with "real" avionics (say, EFIS+GPS+autopilot), the configuration options of an engine analyzer are pretty straightforward.

    It's something that even a talented owner could do with A&P supervision and sign-off.

    - Martin
     
  27. CA182R

    CA182R Pre-takeoff checklist

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    I think Garmin even allows the GI 275 EIS to be installed by A&P (ie. outside of their dealer network). But I don't know if there are special restrictions such as connecting to other avionics.