The FAA has made it much easier for aircraft owners to install angle-of-attack (AOA) indicating systems in light aircraft, and avionics manufacturers have responded with relatively low-cost products that could help prevent loss-of-control accidents. AIN recently flew in Garmin’s AOA-equipped A36 Bonanza to see how the company’s AOA system works.

AOA systems measure the acute angle between the chord line of the wing and the relative wind then display the airplane’s AOA condition on a cockpit instrument or on the primary flight display.

Starting at $1,499, Garmin’s AOA system consists of three components: the GI 260 AOA indicator, GAP 26 probe and GSU 25 air-data computer.

On the Garmin A36, the GI 260 is installed on the left side of the compass on top of the glareshield, so it could easily been seen by the pilot in the left seat, although it was not oriented toward the right-seater’s view. The A36 is equipped with Garmin’s G1000 avionics suite, but Garmin doesn’t offer an AOA indication on the G1000 with this AOA package. For the experimental amateur-built market, Garmin does offer the option of displaying AOA on its G3X avionics primary flight display.

What makes the Garmin AOA easy to install is the GAP 26 probe, which is fitted to an inspection plate positioned under the Bonanza’s right wing. The GSU 25 is hooked up to the probe and to static pressure. Once installed, the system must be calibrated by flying the airplane and matching the approach AOA indication to the typical 1.3 Vso approach speed. “Once the AOA angles have been calibrated, they will be accurate in the calibrated flap configuration, at any gross weight or altitude, every time,” according to the Garmin AOA system owner’s manual.

The AOA system automatically indicates AOA after the airplane reaches at least 50 knots. The pilot can view the symbols on the GI 260 indicator, which also provides aural warnings through the audio system.

In normal flight there usually is no indication showing on the GI 260. As we slowed the Bonanza down, green bar annunciators started showing up on the bottom of the instrument. At 1.3 Vso, the instrument shows the approach AOA reference dot flanked by two green bars. From here, the next bar is yellow, then it transitions to yellow then red chevrons. The aural warnings start as slow beep-beeps with the first yellow chevron. These warnings then speed up as the red chevrons illuminate. Just before the airplane stalled, the entire indicator lit up while it beeped rapidly.

The proper way to handle this situation is to lower the nose, which matches the downward-pointing direction of the red and yellow chevrons, and doing so quickly returned the AOA indicator to the safe green bars and AOA reference dot.

The Garmin AOA system is uncomplicated and priced to encourage aircraft owners to install the device and realize the benefits of AOA indicators. And as more aircraft are equipped with AOA indicators, flight instructors will spend more time not only learning how they work but teaching the important concept of AOA and how relying on airspeed can leave little margin for error.