Anemometers: services will only use approved anemometers to measure surface winds during all personnel and cargo parachute operations. The approved anemometers are the DIC-3 and the Turbometer. The DIC-3 and Turbometer cannot be calibrated; they must be given an expedient check before use.Ensure fresh batteries are installed in the anemometer.Check the anemometer in a no wind condition such as in a vehicle cab or a building. Turn on the anemometer and if any reading other than zero registers, the anemometer is not fit for use and must be discarded.Use a three-anemometer check by comparing the reading on three anemometers in identical conditions. Discard the one anemometer that doesn’t read the same as the other two.