Don't be alarmed by the alarms Published May 28, 2008 By Staff Reports 100th Air Refueling Wing Public Affairs RAF MILDENHALL, England -- During the course of the next few weeks, RAF Mildenhall will be testing its Klaxon system. The Klaxon is an alarm system used to notify aircrews on alert status when they need to report to their aircraft. The tests, beginning June 4, will take place the next three Wednesdays at 11 a.m. Each test will last about five to 10 seconds. The klaxon is audible in and around several buildings on base.