Airworthiness Directives; Dassault Aviation Airplanes
We are superseding Airworthiness Directive (AD) 2011-16-01 for all Dassault Aviation Model FALCON 7X airplanes. AD 2011-16-01 required adding an automatic reversion logic and a means for the pilot to override pitch trim control normal modes, and installing placards in the cockpit; replacing the frame of the emergency switch box; replacing certain horizontal stabilizer electronic control units (HSECU); revising the Limitations section of the airplane flight manual (AFM); and revising the maintenance program to incorporate a certain task. This new AD requires modifying the fly-by-wire (FBW) standard; and operational testing of the electric motors reversion relays and trim emergency command of the horizontal stabilizer trim system (HSTS), and repairs if necessary. This AD was prompted by an uncontrolled pitch trim runaway during descent. We are issuing this AD to prevent an uncontrolled pitch trim runaway, which could result in loss of control of the airplane.