Envelope Protection Comes to GA

Systems from Garmin and Avidyne that aim to prevent loss-of-control accidents are already showing up in light airplanes. Here's how one of them might just save your life.

To see the envelope protection capabilities of the GFC700 autopilot, I simulated a level-off on an approach with full flaps and the power retarded. The system kept the airspeed at 70 knots while allowing a rate of descent of around 550 fpm to maintain that airspeed while giving visual and audible alerts of "airspeed."

The Avidyne DFC90 digital autopilot, a slide-in replacement for the popular S-Tec 55X, features extensive envelope protection when the autopilot is turned on.

The DFC90 features overspeed protection. On this maneuver, with the autopilot off, I put the nose down and let the airspeed build to just shy of the SR22's VNE of 201 kias. I then activated the autopilot, which raised the nose to prevent exceeding VNE.

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Flying StaffEditor

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