Embraer has paused the flight test program on its KC-390 medium-lift, multi-mission aircraft after an unplanned upset in early October, said the company in a statement. The twin-jet was performing tests on its slow flight characteristics with simulated ice formation at 20,000 feet, according to the company. In attempting to recover to cruise flight, Flightradar24 data shows the KC-390 prototype losing 17,000 feet before ADS-B coverage was lost, at one point reporting a vertical speed of -31,000 feet per minute.
The Brazilian aerospace contractor has been coy on the nature of the test incident, except to say that “all aircraft systems behaved as expected throughout the flight.” An unnamed engineer says test equipment came loose during the flight and slid aft, moving the center of gravity to an almost unrecoverable position, according to Brazilian Aero Magazine. Aero Magazine reports that Embraer denies the upset was related to movement of the center of gravity or the fly-by-wire control system.
Embraer, in their public statement on the incident, reported that the aircraft was not structurally damaged and will return to flight after repair of some external pieces damaged by overspeed during the recovery maneuvers. The company says the KC-390 is still on track for certification next year, when the Brazilian air force is expecting to take delivery of the first two production aircraft. Embraer hopes the KC-390 will compete for contracts to replace aging C-130s built in the middle of last century still in use around the world.
