LONDON—The FAA is calling on Bell to introduce additional protections into the fly-by-wire control system of its new Model 525 intermediate-heavy twin-engine helicopter. The regulator has issued a special conditions document urging the introduction of a Flight Envelope Protection (FEP) algorithms that would stop the pilot or the aircraft’s autopilot from forcing the aircraft to “exceed its structural, aerodynamic or operating limits.” The FAA’s calls have been ...