Robinson R44
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 90; Flight Crew Total 8000; Flight Crew Type 400
Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Diverted; Flight Crew Landed in Emergency Condition; General Flight Cancelled / Delayed; General Maintenance Action
Aircraft
We had a rupture of the upper mast bearing in flight; which caused contamination and condemnation of the MGB (Main Gear Box) due to corrosion of this bearing and its parts that entered into the main gear box. The MGB chip light did not light and the flight was interrupted at the Captain's discretion without any accidents or casualties. There is no inspection or verification procedure for this bearing before overhaul (2;200 hours) and I consider this a very serious maintenance inspection failure. The manufacturer is checking with the technical industry for perhaps issuing inspection service bulletin of this bearing before overhaul.Our helicopter is only 1;040 hours totals; all the revisions and inspections were done and the try-rap of mast was in good condition; but this bearing was very corroded and we almost had a tragic consequence. If this bearing had been inspected more often this dangerous situation we had could have been avoided.I ask them to acknowledge and check the progress of the issuance of this service bulletin so that we have no possibility of accidents with the R44 of the world fleet.
R44 Captain reported a failure of the upper mast bearing that resulted in a diversion.