VIBRATION MONITORING & ANALYSIS IS RECOGNIZED AS A KEY COMPONENT OF A WELL-FOUND RCM (Reliability Centered Maintenance) PROGRAM. MACHINERY HEALTH AND LONG-TERM RELIABILITY IS INTERPOLATED FROM TRENDS IN VIBRATION AMPLITUDE, HOWEVER, OFTEN THESE LEVELS INCREASE TO DANGEROUSLY HIGH VALUES WITH LITTLE OR NO WARNING! RESONANCE IS FREQUENTLY IDENTIFIED AS THE ROOT CAUSE, AND UNDERSTANDING THE PHYSICS OF NATURAL FREQUENCY, AND THE TOOLS AND METHODS USED TO RECOGNIZE AND CONFIRM A RESONANT CONDITION ARE ESSENTIAL SKILLS FOR THE VIBRATION ANALYST.