Brazil's ATC software is badly designed, contributing to an "unsafe and dangerous" system, the International Federation of Air Traffic Controllers' Associations (IFATCA) alleges. The radar display will automatically indicate a change in altitude to the assigned flight level, without confirmation from a controller, it says. Thus, the screen apparently showed the Legacy jet at FL360, as assigned, even though no communications between the pilots and ATC confirmed the change in altitude, IFATCA says, and the jet never made that change. "Information we have gathered tells us that this 'discrepancy' happens several times a day and is a 'common scenario' for ACC Brasilia...IFATCA believes that operators in the air (the pilots), and on ground (the controllers), fell victim to unacceptable systems traps brought on by non-error tolerant and bad system design of air traffic control and flight equipment in use."
In the Legacy cockpit, it's easy for pilots to accidentally turn off the transponder, thus disarming the TCAS, and the system's warnings are inadequate, IFATCA said. The situation creates "a dangerous trap for pilots." According to Honeywell, "The initial report from the investigation team does not identify any evidence to indicate that Honeywell's equipment failed at any time during the flight. While the report does indicate that the transponder was not on at the time of the collision, there is no evidence that the transponder or radio management unit was defective or malfunctioned in any way. Honeywell's equipment is certified by the National Agency of Civil Aviation (ANAC) in Brazil, the U.S. Federal Aviation Administration and the Joint Aviation Authority in Europe. Pilots who fly these aircraft are trained to operate this equipment and receive annual retraining every year. Honeywell is not aware of any operational issues with either the transponder or the radio management unit in the Embraer Legacy aircraft."