The characteristics of a required sensor can directly affect the number of nuisance alarms of a Windshear Detection and Guidance System and, in some applications, be a prime factor in determining the detection threshold level of the system. The problem is aggravated in the retrofit of commercial airliners whose sensor technology may be outdated. Sometimes, a required sensor does not exist on the aircraft and must be installed. In other cases, a sensor may be available but both the static and dynamic accuracy may be in question. Since it is not economically feasible to replace all older sensors, means must be found to compensate for known inaccuracies. The availability of sensors required for retrofitting the Honeywell Windshear Detection/Guidance System and the impact of sensor inaccuracies on both detection and flight guidance will be discussed.