Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede an existing airworthiness directive (AD) that applies to all Dassault Aviation Model FALCON 7X airplanes. The existing AD currently requires 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); operating the airplane according to the limitations and procedures in the airplane flight manual (AFM); revising the Limitations section of the AFM; and revising the maintenance program to incorporate a certain maintenance planning document (MPD) task. Since we issued that AD, Dassault Aviation has developed a modification of the fly-by-wire (FBW) standard; changed the AFM to incorporate changes resulting from the FBW modification; and revised the airplane maintenance manual (AMM) to incorporate repetitive operational tests of the electric motors reversion relays and trim emergency command of the horizontal stabilizer trim system (HSTS). Once incorporated, these actions allow restoration of the originally certified minimum equipment list items. This proposed AD would retain certain requirements of the previous AD; would require modifying the FBW standard; operating the airplane according to the limitations and procedures in an approved AFM; and operational testing of the electric motors reversion relays and trim emergency command of the HSTS, and repairs if necessary. We are proposing this AD to prevent an uncontrolled pitch trim runaway, which could result in loss of control of the airplane.