after eliminating all individual and combined sources of mechanical failure, the ntsb ruled that the extension of the slats was due to the flight crew manipulating the flap/slat controls in an inappropriate manner. investigators believed that 727 pilots (in general, and this flight specifically) were setting the trailing edge flaps to two degrees during high altitude cruise, while at the same time pulling the circuit breaker for the slats so that they would not activate. this configuration was rumored to result in increased lift with no increase in drag, thus allowing more speed, higher elevation, or decreased fuel consumption. flaps and slats were intended to only be deployed at low speeds during take-off or landing.