MARITIME HELICOPTERS, INC

Operated by Maritime Helicopters (per NTSB report)

Operated by MARITIME HELICOPTERS INC (per NTSB report)

Operated by MARITIME HELICOPTERS INC (per NTSB report)

ON JULY 22, 2021 AT APPROXIMATELY 0920, INFLIGHT AND IN IMC WHILE PERFORMING THE RNAV RWY 5 APPROACH INTO PAAD THE CREW EXPERIENCED A TEMPORARY LOSS OF VERTICAL AND LATERAL COURSE GUIDANCE AND A CASCADING PRESENTATION OF CAS MESSAGES INCLUDING AMBER: AGM 2 FAIL, APM FAIL, MAU B FAIL, CHECK COPILOT PFD, ASCB FAIL, UNABLE FMS-GPS MON AND CYAN: CMS 2 FAIL, AP 1 FAIL, FD 1 FAIL, YD 1 FAIL, TCAS FAIL, MONITOR FAULT, CAS B FAIL, AURAL WARNING FAULT, AIOP B FAIL AND GIO B FAIL. THE CAS MESSAGES WERE PRESENTING A CONTINUOUS AND REPEATING DISPLAY CYCLING ON AND OFF. ALSO INTERMITTENTLY REMOVED OR INOPERATIVE WERE THE FMS WAYPOINTS, THE PILOT AND COPILOT PFDS, COPILOT ALTIMETER, BOTH PILOT'S SYNTHETIC VISION AND THE INAV DISPLAY, WHICH LOST COURSE GUIDANCE AND WAYPOINT DISPLAY. SHORTLY AFTER THE FAILURE BEGAN THE SYSTEM SLOWLY RETURNED TO NORMAL. THE APPROACH CONTINUED TO A NORMAL LANDING. AFTER LANDING IN PAAD, ON ROLL OUT ANOTHER FAILURE TOOK PLACE IDENTICAL TO DESCRIBED ABOVE AND CONTINUED UNTIL SHUT DOWN ON THE RAMP. AFTER CONFERRING WITH MAINTENANCE A NORMAL AIRCRAFT POWER UP WAS DONE AND 3-4 MINUTES INTO THE POWER UP THE SYSTEM FAILED AS PREVIOUSLY LISTED ABOVE. AFTER CONSULTING WITH OEM (VIKING) TECHNICAL SUPPORT, COMPANY MAINTENANCE FOUND A POOR SOLDER SPLICE BETWEEN THE #2 NETWORK INTERFACE CARD AND THE AIRCRAFT STANDARD COMMUNICATION BUS. MAINTENANCE TESTED ALL THE WIRING AND PIN CONNECTIONS FOR THE MAU MODULES AND FOUND NO FURTHER BAD SPLICES OR CONNECTIONS.

DAILY AIRCRAFT CHECK NOTED DENTS ON TAIL ROTOR BLADES OUTER SURFACE. NON-SHARP DENTS ON OTBD FACE OF BOTH BLADES. NO INDICATION OF STRIKE TO BLADE L/E.

OIL COOLER CRACKED INTERNAL OF COOLER FINS CAUSING OIL LEAK.

DURING NORMAL 600-HOUR/12-MONTH INSPECTION AND REPACK OF MAIN ROTOR DRIVESHAFT, DISCOVERED A GEAR TOOTH (ON THE END) OF THE OUTER COUPLING WAS CHIPPED. SUBMITTER SIFTED THROUGH THE GREASE, BUT COULD NOT FIND ANY EVIDENCE OF THIRD CHIP. PART WAS RED-TAGGED AND DESTROYED. A NEW OUTER COUPLING OF SAME PART NUMBER INSTALLED AND AIRCRAFT RETURNED TO SERVICE. (X)