On this Baron YT video:

what are the two devices sitting on top of the instruments panel, on both sides of the compass?

YT screenshot

I though at first it is some kind of HUD (Head-Up Display), but it looks way too small, compared to, for example, this Garmin device.

I tried to zoom in to see the marking on the left one but no success.


2 Answers 2


It’s a STC head up display angle of attack kit. In addition to an angle of attack sensor being installed on the exterior of the aircraft, this device provides eye-level display of an angle of attack indicator. They’re becoming increasingly popular in general aviation airplanes and provides an additional sense of angle of attack, especially during low speed maneuvers.

You can see a similar STC part here


  • 1
    $\begingroup$ Oh my god the product in the link! Talk about confusing and counterintuitive symbology!!! $\endgroup$
    – Jpe61
    Aug 8, 2021 at 16:18
  • $\begingroup$ I’m not sure why you would call it confusing per se. It displays the same info as any other angle of attack indicator. $\endgroup$ Aug 8, 2021 at 16:32
  • 1
    $\begingroup$ Wedges, triagles, a split ball, a line. Designers of this system forgot the KISS principle. I have a hunch I've seen this symbology in a military HUD somewhere, not sure. If it in fact is copied from a military system, it is still unnecessarily complicated. $\endgroup$
    – Jpe61
    Aug 8, 2021 at 18:08
  • 6
    $\begingroup$ @Jpe61 Other than the see-thru nature of it, this looks very much like the AoA indexer I remember from the T-38. Having flown with it for a while, it became quite familiar and intuitive to refer to in flight. $\endgroup$
    – Ralph J
    Aug 8, 2021 at 19:25
  • 7
    $\begingroup$ @Jpe61 Don't confuse violation of the KISS principle with your own lack of familiarity with the indications. It is a quite simple and intuitive display, inherited from military aircraft, when you have become acquainted with it. Most instruments in aircraft, even the best designed modern ones, can look counterintuitive to those unfamiliar. $\endgroup$
    – TypeIA
    Aug 8, 2021 at 21:06

This is an Angle Of Attack indicator, specifically Alpha Systems’ Eagle Above Dash HUD Kit:

enter image description here

  • $\begingroup$ Thanks for that link! The operation and installation manuals give a good explanation on the principles (measuring the air pressure difference on two nearby locations, from what I understood). $\endgroup$
    – kebs
    Aug 9, 2021 at 9:52
  • 1
    $\begingroup$ Appropriate that they're mounted next to a little eagle statuette... $\endgroup$ Aug 9, 2021 at 19:31

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