New airplane, finished initial phase of flight test, no issues to speak of.

Now the background:
First attempt to do an engine run (few months back). Lane A and B indicate RED for 3-4 seconds, then go out . . . except for lane A; it goes to about half brilliance. No faults logged. After various conversations with the Vans guys, they said "no worries, go ahead and run the engine". Engine ran great.
After a couple of ground runs, I notice that it (Lane A annunciation) no longer has the half brilliance situation. All is normal.
Flew Phase 1 - all is good

Now the problem:
Flew today (about 6-7 hours total on the aircraft at this point), the Lane A light is doing it again. No faults logged, and all else looks/acts normal.
All interconnect has been inspected and metered to print.  Both lights are interfaced the same and are the "standard" RV-12 annunciations (LED).

Thx Guys!


After a fairly long conversation with the Van's guy (sorry, forgot his name but he was really good at electrical things), his conclusion was an internal fault of some sort on the ECU. . . But not a "log-able" fault.

Any ideas?

  • Re: Lane A status light partially illuminated

    by » 4 months ago

    It sounds like the 1.5K Shunt Resistor in the Lane A Lamp Circuit could be intermittent.
    The Lane Lamp circuit was designed with Incandescent lamps in mind.
    The leakage current in the OFF state is not enough to affect an Incandescent bulb but is more than enough to illuminate an LED Lamp.
    The Shunt Resistor drains off the leakage current.
    It will cause No Faults if it goes OPEN Circuit but it would allow the LED to illuminate dimly.

    It could be just a bad solder joint.

    The Lamp Circuit is shown in the 912is Installation Manual, Chapter 24-00-00, Page 32, Fig. 3.14,  in the Upper Left Corner of the drawing.
    Also, read the notice at the top of Page 24.

    Bill Hertzel
    Rotax 912is
    North Ridgeville, OH, USA
    Clicking the "Thank You" is Always Appreciated by Everyone.

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