 It has quadruple-redundant fly-by-wire flight controls.To lower development costs, the avionics, fly-by-wire systems, and other parts were derived from the General Dynamics F-16 Fighting Falcon, McDonnell Douglas F/A-18 Hornet and McDonnell Douglas F-15E Strike Eagle.The parts were originally described as spares on budgets for these aircraft, to keep the F-117 project secret.