ZIP AVIATION LLC

Operated by Zip Aviation (per NTSB report)

THIS IS TO REPORT A NEW EVENT FOLLOWING SDR NO. 2120-0663. THE REPAIRED ENGINE WAS TAKEN OUT OF SERVICE FOR THE ENGINE SMOKE WHEN ENGINE TRANSITIONS FROM FLY TO IDLE. TROUBLESHOOTING WAS CARRIED OUT PER THE ROLLS ROYCE MANUAL. NO DISCREPANCIES WERE NOTED. THE REPAIR WAS PERFORMED BY PHI AS PREVIOUSLY NOTED. PHI WAS NOTIFIED ABOUT THE EVENT. THIS EVEN OCCURRED APPROXIMATELY 65 HOURS AFTER REPAIR OF A SIMILAR ISSUE DESCRIBED IN THE SDR NOTED EARLIER IN THIS DESCRIPTION.

UNKNOWN INTERNAL ENGINE COMPONENT CAUSING BURNING OF OIL AFTER ENGINE OVERHAUL AND REPLACEMENT OF ALL 4 TURBINE WHEELS.  FIRST OCCURRENCE RECORDED AFTER SMOKE WAS OBSERVED COMING FROM THE EXHAUST WHEN THE AIRCRAFT WAS AT IDLE AND DURING SHUTDOWN AFTER A FLIGHT ON 7/23/2025, ENGINE TSO: 13.9 HRS. TROUBLESHOOTING OF ENGINE AND AIRFRAME SYSTEMS COORDINATED WITH PHI (WHO PERFORMED THE PRIOR MAINTENANCE) AND ASSIGNED ROLLS ROYCE TECH REP.  OIL APPEARED AND SMELLED BURNED.  NO CONCLUSIVE CAUSE FOUND.  ENGINE WAS REMOVED FROM SERVICE AND RETURNED TO PHI FOR A TEAR DOWN INSPECTION.  DURING THE INSPECTION TIME, A RENTAL ENGINE ACCUMULATED 170.5 HOURS ON THE SAME AIRFRAME WITH NO DISCREPANCIES.  NO CONCLUSIVE CAUSE WAS FOUND DURING PHI'S TEAR DOWN INSPECTION.  ENGINE RETURNED TO ZIP AVIATION AND REINSTALLED ON THE SAME AIRFRAME ON 10/11/2025.  ON 1/8/2026, TSO: 272.2 HRS, SMOKE WAS AGAIN OBSERVED COMING FROM THE EXHAUST AT IDLE AND SHUTDOWN AFTER A FLIGHT.  TROUBLESHOOTING FOUND NO CONCLUSIVE CAUSE.  OIL APPEARED AND SMELLED BURNED.  ENGINE WAS REMOVED FROM SERVICE AND SENT BACK TO PHI FOR ADDITIONAL INSPECTION/TROUBLESHOOTING.  NUMEROUS PARTS OF THE ENGINE HAVE BEEN REPLACED DURING THIS TIME.  AFTER APPROXIMATELY 4 HOURS OF RUNNING ON THEIR TEST CELL, OIL IS STILL BEING FOUND TO BE BURNED.  TROUBLESHOOTING IS STILL IN PROGRESS.  PHI'S THEORY IS THE DISCREPANCY IS INTERNAL OF THE TURBINE MODULE.  OPEN

PILOT REPORTED HEARING A LOUD (THUMP NOISE) WHEN THE AIRCRAFT WAS PICKED UP TO A HOVER DURING REPOSITIONING FROM ONE HELI-PAD TO ANOTHER @ KJRB OPERATIONS. WHEN THE TECH TEAM WAS DISPATCHED, THEY DISCOVERED THE BOTTOM AFT LH LIFT LINK HAVING EXCESSIVE PLAY. AIRCRAFT WAS RECOVERED VIA GROUND TRANSPORT TO BASE. ONCE THE TRANSMISSION ASSEMBLY WAS REMOVED WE DISCOVERED THAT THE LH AFT LIFT LINK BOTTOM IS IN FACT CRACKED AND THE ELASTOMERIC BEARING IS DIS-BONDED AND NO LONGER INTACT. FILED CASE 00231811 WITH BHT PRODUCT SUPPORT TEAM.