Frequently Asked Questions


			Answers to Frequently Asked Questions

			Do I need to complete a Form 337 for a dynamic propeller balance?

			Not always. If the manufacturer has an established written procedure for the dynamic balance of the propeller, no 337 is required. If no such guidance is available, you may use the information in FAA Advisory Circular 20-37E (or subsequent) and the FAA-approved document "ACES Systems Guide to Propeller Balancing" as reference material. Remember that this is in lieu of any available guidance from the manufacturer which would always take precedence. The requirement for the 337 is spelled out in AC20-37E.

			Is ACES equipment approved by the FAA?

			No. It isn’t required to be approved by the FAA. The analyzer you use, ACES Systems or otherwise, is only a tool much as a wrench or screwdriver. As such, the equipment itself needs no approval. The FAA approval often confused with this assumption is in the hardware and associated methods of application needed to accomplish the dynamic balance. To say ACES Systems' equipment (or any other equipment) is FAA approved is misleading. To say a balance job done with ACES equipment (or any other equipment) is FAA approved is also misleading. The only portion of the job that requires an FAA approval is the actual hardware and associated methods of application used to accomplish the task. ACES publishes an FAA-approved document which spells out these requirements of hardware and methods. The "ACES Systems Guide to Propeller Balancing" is provided with each propeller balancing kit sold by ACES Systems or you can download one from the Manuals page of this web site. You may use the guide with any balancing equipment and be assured that it is FAA-approved.

			I balanced my customer's propeller down from .5 IPS to an acceptable level of .06 IPS with an ACES Systems' balancer but I could still feel vibration in the yoke and rudder pedals. What did I do wrong?

			Nothing. When you balance the propeller you are balancing at a specified frequency, the RPM you selected as a balance speed. In doing so, your balancer displayed the once-per-rev synchronous vibration associated with that frequency. Anything vibrating outside that frequency isn't displayed in the propeller balancing program. Other components may be vibrating at different frequencies. You may also be feeling a resonate vibration in the airframe structure that has been excited by the propeller or other fundamental frequency source. If you perform a vibration or acoustic survey and read the overall vibration you should see a level (IPS) higher than that being read from the propeller assembly. Having an operating frequency chart of common components for the aircraft will greatly simplify the task of pin-pointing the source of the vibration. A full graphics spectrum survey can be accomplished using a Model 2020 ProBalancer Analyzer or any one of the ACES Systems 1700 series analyzers.

			I own another brand of balancer with all the sensors recommended to do a track and balance on my helicopter. If I upgrade to an ACES Systems' Model 2020 do I need to buy all new sensors to fit it?

			No. The Model 2020 ProBalancer Analyzer uses a wide range of sensors. The analyzer can be programmed to use most sensors you own. In some cases we may even have an adapter that allows you to use the cables you also have. If not, we build cables for most sensors. We also work with individual needs. If we don’t have the cables or sensor you need, we will be happy to find them and build the necessary cables to use them. Contact ACES Systems for more information.

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