Garmin GAP-26 Heated Pitot Tube with AOA, Regulated.
The GAP 26 pitot/AOA probe is available in three versions: unheated, non-regulated heated, and fully-regulated heated. The latter two are heated probes. For both heated versions, the pilot throws a switch to turn the heat on.
The heated, regulated version of the GAP 26 (010-010704-20) has a small box with the regulating circuitry that is mounted near the probe. This version of the GAP 26 probe is also equipped with an internal temperature sensor which the regulating circuit uses to supply as much current as the probe needs to remain ice free. This current, of course, varies with the operating conditions.
The heated, regulated version of the GAP 26 also provides an output discrete that G3X uses to provide alerts related to the heated probe. The alert configuration is configurable in several ways, but one configuration is described below.
You get in your plane on a cold day when the temperature is below 7 degs C (45 degs F) and power on your avionics with the pitot heat switch turned off. A yellow “PITOT TEMP” alert message pops up on your PFD reminding you that it is cold enough that you might want to turn on your pitot heat. You turn your pitot heat on and as soon as the pitot probe temperature rises above approximately 25 degs C (77 degs F) the yellow “PITOT TEMP” annunciator goes away, and you are ready to fly. If you are flying along and experience a problem with your pitot heat and the probe gets too cold the yellow “PITOT TEMP” annunciator will pop up on your PFD as a warning that your pitot probe heat is not working.
The probe temperature is regulated to approximately 75C to 80C (167F to 176F) so, even on a very hot day, you will still be able to tell the probe is heating up if you turn it on and carefully perform a ramp check. With the active monitoring built-into the heated, regulated probe, the ramp check shouldn’t be necessary.
People buy the regulated version of the GAP26 when they want to both not draw any more power from their alternator than necessary, and also want active monitoring of the pitot temperature to let them know if there is a problem.