Results 1 to 7 of 7

Thread: Tach and Hobbs Timer Incorrect

  1. #1

    Tach and Hobbs Timer Incorrect

    On a very long cross country the Hobbs time didn't seem to agree with my watch or GNS430 timer. While in cruise flight, the elapsed time (about two hours) of the AF-2500 is off by about 12-13%.....it shows less time than actual. It also seems to be a bit variable.....about 12% for one test, about 13% for another test on another day. Does AFS know what would cause this, if it could be variable, if it likely existed since the unit was new? I have used this timer for all log book entries (flight and maintenance) over the last 1100 hours or so......not good.
    Last edited by Mark Spickard; 07-25-2018 at 11:20 AM.

  2. #2
    Advanced Flight Systems Shawn McGinnis's Avatar
    Join Date
    Sep 2012
    Location
    Canby, OR
    Posts
    861
    Are you getting stable RPM readings? For the AF-2500, tach time is hours on engine above 1250 RPM. Hobbs Time is hours on engine above 0 RPM.
    Shawn McGinnis

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

  3. #3
    Quote Originally Posted by Shawn McGinnis View Post
    Are you getting stable RPM readings? For the AF-2500, tach time is hours on engine above 1250 RPM. Hobbs Time is hours on engine above 0 RPM.
    RPM is stable. While in continuous cruise flight, the elapsed tach and hobbs time are the same....and both in error. The clock is always correct. I have dual lightspeed ignition and I have the electronic adapter box you guys provide to get rpm signal from the lightspeed to the analog unit.

  4. #4
    Advanced Flight Systems Shawn McGinnis's Avatar
    Join Date
    Sep 2012
    Location
    Canby, OR
    Posts
    861
    I'm not seeing any notes with time accumulation issues. Can you check which version of software your AF-2500 is running using the TIME button?
    Shawn McGinnis

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

  5. #5

  6. #6
    Advanced Flight Systems Shawn McGinnis's Avatar
    Join Date
    Sep 2012
    Location
    Canby, OR
    Posts
    861
    I don't see any software updates that make changes to this portion of the AF-2500 code. You probably have a hardware issue in the display. Call Tricia at 503-263-0037 x 2 and she can set up an RMA for diagnosis.
    Shawn McGinnis

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

  7. #7
    Mark, did you get a resolution to this issue?
    I have what appears to be the same thing happening with my AF-3500 (non S).
    Looking at a selection of data logs over the years it seems it may have started happening since it clicked over 1000 hrs recently.
    It takes 1 hr, 8 mins & 15 seconds of flight time to register a change of 1.0 on the Tach & Hobbs.

    I've been tempted to reset the Tach & Hobbs back to zero to see if the issue goes away.

    Thanks,
    Chris

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •