Certain software issues that Embraer 170 and 190 operators experienced with the airliners' highly integrated Honeywell-built Primus Epic avionics suite have been resolved.
Honeywell says that between the time that the US Federal Aviation Administration opened for comment a proposed airworthiness directive on the issue and on 29 August, Honeywell released an updated software load, 21.2, which addressed the agency's concerns.
"As a result, all US operators have installed 21.2 and are in compliance with the AD," says the manufacturer.
The Primus Epic handles the digital avionics, integrated utilities and fly-by-wire flight controls on all E-Jets. It had been found that some "caution" messages issued by the flight guidance control system (FGCS) are not displayed on aircraft equipped with certain earlier Epic software loads.
Therefore, says the FAA in a final AD issued in August, following a possible failure on one FGCS channel during a given flight, such a failure condition will remain undetected.
If another failure occurs on the second FGCS channel, the result may be a hardover command by the autopilot, which could cause a sudden roll, pitch, or yaw movement, resulting in "reduced controllability" of the aircraft.
Source: Flight International
