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Thread: On the ground - in the hanger - EFIS says we're doing 29-31 KIAS!

  1. #1

    On the ground - in the hanger - EFIS says we're doing 29-31 KIAS!

    I have checked my entire pitot and static systems for a blockage.
    Went so far as disconnecting the pitot and static sources at the back of the display - still shows airspeed.

    Is there a way to calibrate the zero-baseline? Although the numbers match the steam guages when I am actually flying - and I just did the homemade tests with the manometer and vacuum puller. System is tight.

    Is there a way to tell the device - you're on the ground and not flying - in order to perform log retrievals? Getting system data is disabled when the unit thinks it is flying!

  2. #2
    Advanced Flight Systems Shawn McGinnis's Avatar
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    Call us from the display and we can walk you through the process. 503-263-0037 x 1
    Shawn McGinnis

    Advanced Flight Systems
    support@advanced-flight-systems.com

  3. #3
    I called in and the gent I talked to indicated you would send an instruction set as I am not local to the plane during the week.

    Thinking the instruction set is for the screen interface.

    I'm thinking that would modify the AIRDATA.AFC file:

    AIRSPEED.NUM_CAL_PTS, 16
    AIRSPEED.TEMP_CAL_AD_VALUE, 2590
    AIRSPEED.HI_TEMP_SLOPE, -50
    AIRSPEED.LOW_TEMP_SLOPE, 42
    AIRSPEED.DISPLAY_VALUE_1, 0
    AIRSPEED.AD_VALUE_1, 660
    AIRSPEED.DISPLAY_VALUE_2, 300
    AIRSPEED.AD_VALUE_2, 929
    AIRSPEED.DISPLAY_VALUE_3, 400
    AIRSPEED.AD_VALUE_3, 1158

    Am I on the right track here?

    Thanks!

  4. #4
    Using the instructions provided, it appears to have set things to working correctly again!

    Here's what the AIRDATA.AFC file looks like now:

    AIRSPEED.NUM_CAL_PTS, 16
    AIRSPEED.TEMP_CAL_AD_VALUE, 2590
    AIRSPEED.HI_TEMP_SLOPE, -50
    AIRSPEED.LOW_TEMP_SLOPE, 42
    AIRSPEED.DISPLAY_VALUE_1, 0
    AIRSPEED.AD_VALUE_1, 824
    AIRSPEED.DISPLAY_VALUE_2, 300
    AIRSPEED.AD_VALUE_2, 929
    AIRSPEED.DISPLAY_VALUE_3, 400
    AIRSPEED.AD_VALUE_3, 1158

    I will update after the next flight - but since it shut off 'normally' and allowed me to download my data, I think we have a good solution.

    Thanks Shawn!

  5. #5
    After the flight, it still showed 28 KIAS of airspeed - I manually shut it down.
    After getting it in the hangar and putting the pitot tube cover on, I restarted it to get my data - airspeed shows as zero now.
    There was a little wind out there and it was a crosswind I had turned in to when I shut down so I can put the plane directly back in the hangar.

    Thoughts about making the "AIRSPEED.AD_VALUE_1, 824"
    read like "AIRSPEED.AD_VALUE_1, 860"? Still gives me 50 points before the VALUE_2 entry....

    I really like the automatic shutdown as it doesn't kill the backup battery.

  6. #6
    Advanced Flight Systems Shawn McGinnis's Avatar
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    Quote Originally Posted by recapen View Post
    and putting the pitot tube cover on
    Most pitot covers cause the airspeed to change. Have you tried removing the cover? You could add a small hole in the front to allow venting.
    Shawn McGinnis

    Advanced Flight Systems
    support@advanced-flight-systems.com

  7. #7
    In this case, the airspeed went to zero WITH the cover on. I'm trying to get the machine to ignore ground wind.
    Would increasing the "AIRSPEED.AD_VALUE_1" setting to a higher number like 860 help increase the 'ignore' factor?

  8. #8
    Advanced Flight Systems Shawn McGinnis's Avatar
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    Yes that would do it. If the cover was on when you recalibrated the settings it would have had pressure from the cap creating a higher reading. The hole in the cap will fix this for future baro pressures.
    Shawn McGinnis

    Advanced Flight Systems
    support@advanced-flight-systems.com

  9. #9
    Excellent - thanks - another thing to do this weekend......

  10. #10
    Set it to 869 since the next setpoint was 929 and the instructions indicated a 50 point minimum difference - works fine.
    Thanks for everyone's help on this one!

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