Planet ES-10024B-1 Maintenance Manual page 40

3.4 Continued
J. Whenever the pilot notes belt noise, it is important to determine the type of noise and
under what circumstances it occurs. Repairing a drive misalignment (chirp) is not likely to
resolve a slip noise (squeal) that may be caused by insufficient tension.
(1) Check if the problem is more noticeable when starting and while the engine is cool
(cool wet belt).
(2) Is the noise loudest at idle speed, or when accelerating the engine RPM (rapid
changes in RPM speed can cause a belt to slip).
(3) Try to recreate the problem in the maintenance run area. If the noise is heard, use
a spray bottle or other source of misting water and mist the belt lightly. If the noise
level recedes or goes away for several seconds, then returns, the problem is most
likely misalignment.
(4) If the noise immediately increases after the belt is sprayed, slipping is likely.
(5) If the water spray test is inconclusive and the noise remains unchanged, the
problem is not likely related to drive alignment.
24-30-01
Page: 3-10
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Aircraft Alternator
Maintenence Manual
ES1031
Rev. A: 11 Aug. 2021