Air Data Computers have some unique qualities. One of these is SSEC or Static System Error Correction. High speed aircraft distort the air they fly through such that the static port pressure does not accurately represent the undisturbed air. Data from the development cycle of the aircraft is programmed into the ADC against the speed and the altitude correspondingly increased or decreased at the display. There is a SSEC disable switch on the front of many ADC's during testing.