This Aerospace Recommended Practice (ARP) specifies the requirements of balancing machines that make them suitable for the subject class of work. It was developed for soft-bearing balancing machines but may also be used for hard-bearing machines until ARP4048 is issued for that type of machine.

Particular note should be taken that this ARP examines only the capability of a balancing machine to indicate the correct amount of dynamic or static/couple unbalance in specified proving rotors. Such rotors are commonly used for testing balancing machines to provide precisely controlled and comparable test results. Further tests of a particular machine may be necessary to assess the capability to balance rotors of different weights and configurations, rotors with outboard c.g. and/or correction planes, and those with disturbance causing features, such as rotors subject to blade scatter, windage, etc.

This ARP specifies dimensional and performance requirements in the following areas:

a. Machine capacity relating to weight and physical dimensions of the rotors that can be balanced

b. Accuracy of amount and angle indication

c. Sensitivity and linearity of amount indication

d. Ability to separate dynamic unbalance into two planes or into static and couple unbalance

e. Balancing speed and direction of rotation

f. Drive requirements

g. Proving rotors, test masses, and storage containers