Performed on a routine basis, propellers are balanced using an electronic balancer. Once completed, the full spectrum of engine vibration is recorded using a Chadwick Vibration Analyzer 192A on chart cards, the MicroVib II Aircraft Analyzer (see MORE Service Bulletin 101 for more details), or the ACES GEN II Analyzers covering the ACES Model 2021 Cobra II, ACES Model 4041 Viper II, ACES Model 4041E Viper 2E (see MORE Service Bulletin 104 for more details). Specific speeds (rpm) and balances (ips) are reviewed and identified to the corresponding speeds of critical parts in the engine. The results are used to compare readings from one inspection to the next and any changes are noted or corrected. Increases in vibration can indicate a deterioration of rotating parts. Early identification will keep the engine running safer and keep maintenance costs down.