WASHINGTON (CN) - The Federal Aviation Administration has proposed two sets of new airworthiness safety standards to match new technology in the Embraer EMB-550 transport cargo airplane.
The plane has a high-speed protection system and comprehensive flight envelope protection features not envisioned when federal regulations governing traditional recovery maneuvers were developed, so the FAA has proposed the conditions under which the features would be tested.
The EMB-550's high-speed protection functions within a so called "fly-by-wire" system, which involves computer control of the airplane, so the pilot or co-pilot is not able to maneuver the plane in a way that would take it beyond its structural limitations. The 550's high-speed protection system limits the ability of a pilot to point the nose of the plane down while flying at top speeds, so it cannot perform a particular maneuver from which the plane is supposed to recover, under federal regulations. The new FAA safety test causes the plane to be "upset" such as it would be with a gust of wind, and the plane must not go over safe speeds.
The fly-by-wire system may electronically keep the plane in its so called "flight envelope," or configuration in the sky that allows it to fly, and is meant to help keep the plane stable, even when something happens, such as an engine going out. The EMB-550's "comprehensive flight envelope protection features," include "limitations on angle-of-attack, normal load factor, bank angle, pitch angle, and speed." To keep the plane within its flight envelope, "a significant change (or multiple changes) occurs in the control laws of the electronic flight control system as the limit is approached or exceeded," according to the FAA's proposed conditions. The proposed safety standards are meant to test each flight envelope protection feature.
The FAA's proposed conditions also note that "when failure states occur in the electronic flight control system, flight envelope protection features can likewise either be modified, or in some cases, eliminated." The proposed conditions test these features, also.
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