Expandable Rotorcraft Diagnostics
Main Gearbox Early Planetary Bearing Fault Detection
The XRDS system identified this fault and the RMCI team notified the operator on July 27. On October 17th the main gearbox was removed from service following chip indicators, 100 flight hours after initial notification.
Teardown analysis revealed the source of metal generation was from a planetary bearing. Collateral damage led to replacement of parts throughout main gearbox. The (XRDS) identified this fault two months prior to chip light.
XRDS Main Gearbox
Accelerometer Locations
Metal indentations as well as heavy spalling and pitting found on bearing races
Krēnō Display of multiple flights
Vibration magnitude trend leading up to main gearbox chip indications.
Timeline Of Events
In-flight hours prior to the main gearbox being removed from service
XRDS
100 Flight Hours
RMCI notifies the aircraft operator
of a developing fault in the main gearbox.
Chip 1
30 Flight Hours
Aircraft experiences chip indication and
precautionary landing.
Chip 2
0 Flight Hours
Aircraft experiences 2nd chip indication.
Gearbox removed from service and transmission sent for repair.