Rotax 912 Series Maintenance Manual page 116

Effectivity 912/914 Series
Edition 1 / Rev. 0
BRP-Rotax
Maintenance Manual
Spallation (large zones of the tooth flank have broken off)
See Figs. 72-49 and 72-50.
Characteristics:
Large triangular areas of the tooth flank have broken off, starting in a
grey zone or area of minor pitting on the root of the tooth. The spalling
area is of relatively constant depth. Additional cracks may stretch
across the flank from the main area. In some areas, the damage
reaches the tip area of the tooth, resulting in tooth tip fracture.
Causes:
This type of damage is usually the result of using oil of low viscosity or of
high oil temperatures. Otherwise, the causes are the same as for other
types of pitting.
Conclusion:
■ CAUTION:
If spallation is detected, the gear set must be replaced.
Max. permissible pitting or spallation. See section on advanced pitting.
◆ NOTE:
Figs. 72-49 and 72-50. show triangular spallation.
▲ WARNING: Gears must always be replaced as a set. Replacement
of individual gears is not permissible.
Fig. 72-50
Magn.: approx. 100%
Fig. 72-49
Magn.: approx. 75%
00153
00154
72-00-00
page 48
May 01/2007