INFORMART, CORPORATION

TIRE LOST AIR PRESSURE IN RUN-UP AREA, FOUND TIRE INTERIOR TO HAVE A DEFECT THAT CONTINUED TO CAUSE INNER TUBES TO SLOW LEAK. REPLACED TIER AND TUBE.

ROLL PIN THAT HOLDS PINION GEAR ON SERVO DRIVESHAFT WORKED ITS WAY OUT SO THAT THE GEAR SLIPPED ON THE SHAFT AND THE SERVO WAS MECHANICALLY DISCONNECTED FROM THE FLIGHT CONTROLS. THE SYSTEM DID NOT PROVIDE ANY WARNING OF THIS FAILURE. IT IS ALSO LIKELY THAT A PREVIOUS PITCH TRIM RUNAWAY CAN BE ATTRIBUTED TO THIS FAILURE BECAUSE PERHAPS THE PIN LODGED ITSELF BETWEEN THE GEAR AND CASE OF THE SERVO ON THE WAY OUT. THIS WOULD CAUSE THE SERVO TO JAM AND IT WOULD SENSE EXCESS TORQUE CAUSING THE PITCH TRIM TO ATTEMPT TO COMPENSATE. FORTUNATELY, THIS HAPPENED AT HIGH ALTITUDE IN A REMOTE AREA NOT NEAR OTHER AIRCRAFT AND IT RAN AWAY NOSE UP. HOWEVER, AT LOW ALTITUDE WITH RUN AWAY NOSE DOWN TRIM, IT COULD CAUSE A FATAL ACCIDENT. IN THIS CASE, AT HIGH CRUISE SPEED, THE AIRCRAFT CLIMBED 1000 FEET BEFORE THE PILOT WAS ABLE TO CORRECT THE ALTITUDE DEVIATION.

AIRCRAFT G1000 SYSTEM SHOWED VERSION 17, BUT THERE WAS NO LOG ENTRY FOR APPLICATION OF SERVICE LETTER 1194. A SOFTWARE MISMATCH ERROR WAS NOTED ON A GFC COMPONENT AT 3299 HOURS AND THAT ONE COMPONENT SOFTWARE WAS RELOADED AND ALL SYSTEMS APPEARED TO OPERATE NORMALLY. AIRCRAFT WAS FLOWN FOR APPROXIMATELY 25 HOURS WITHOUT ANY ANOMOLIES. TWO DAYS BEFORE FAILURE, G1000 WAS PLACED IN MAINTENANCE MODE TO CHECK GDU SOFTWARE VERSION TO SEE IF IT WAS CAPABLE OF LP APPROACHES. THE NEXT FLIGHT AFTER THAT, THE FIRST INDICATION OF A PROBLEM WAS THREE LOUD CLICKS IN THE HEAD SET AND APPARENT REBOOTING OF THE AUDIO PANEL AS THE SYSTEM STARTED. THE ACTIVE FREQUENCY DISPLAYED IN THE GDU WAS WHITE INSTEAD OF GREEN, BUT RADIOS APPEARED TO OPERATE NORMALLY. AN AFCS FLAG WAS NOTED IN THE PILOT PFD. RESETTING THE AUTO PILOT AND PITCH TRIM CIRCUIT BREAKERS DID NOT CLEAR THE FLAG. MANUAL ELECTRIC TRIM DID NOT FUNCTION. AFTER TAKEOFF, A WARNING THAT THE TRANSPONDER WAS INOPERATIVE WAS NOTED AND THE TRANSPONDER CYCLED BETWEEN ON, STBY, AND FAIL. FLIGHT WAS DISCONTINUED AND AIRCRAFT RETURNED TO BASE. FOLLOWING GARMIN TECHNICAL SUPPORT ADVICE, A COMPLETE SOFTWARE RELOAD OF VERSION 15 WAS ACCOMPLISHED WHICH RECTIFIED ALL ISSUES.

MANIFOLD PRESSURE OSCILLATED UNCONTROLLABLY FOR 30 SECONDS. REDUCING POWER MAY HAVE STOPPED OSCILLATION. OCCURRED DURING CLIMB AFTER INITIAL POWER REDUCTION. NO FURTHER PRECAUTIONARY PROCEDURES REQUIRED DURING FLIGHT, EXCEPT TO HAVE THE ENGINE INSPECTED AS SOON AS POSSIBLE. INSPECTION REVEALED A CRACK WHERE THE RIGHT TURBOCHARGER ATTACHES TO THE ENGINE OIL SUMP SO AIRCRAFT WAS REMOVED FROM SERVICE PENDING INVESTIGATION BY ENGINE MANUFACTURER.

NR 2 CYLINDER SEPARATED FROM CRANKCASE AT THE MOUNTING BOLTS. ENGINE CONTINUED RUNNING AND SUBSEQUENT SHAKING BROKE EXHAUST MANIFOLD ON LT SIDE BETWEEN CYLINDERS AND TURBOCHARGER. NO HEAT DAMAGE TO SURROUNDING COMPONENTS NOTED PROBABLY BECAUSE AIRCRAFT WAS MOSTLY IN HIGH SPEED DESCENT AT LOW POWER UNTIL SHUTDOWN IN LANDING PATTERN.