LIFE FLIGHT NETWORK LLC

Operated by Life Flight Network (per NTSB report)

DURING FLIGHT IT WAS NOTED AN ABNORMAL METALLIC NOISE EMANATING FROM THE TAIL BOOM AREA. IT WAS DECIDED TO PERFORM A PRECAUTIONARY LANDING DUE TO THE NOISE HEARD. UPON INSPECTION OF THE AIRCRAFT THE TAIL ROTOR MAST NUT WAS FOUND IN A LOOSE CONDITION. SAFETY WIRE WAS STILL INTACT AND IN THE CORRECT ORIENTATION

UPON LANDING WOW CAS MESSAGE ILLUMINATED. DURING INVESTIGATION IT WAS FOUND THE BOLT (AN4-27) THAT SECURES THE TRAILING LINK ASSEMBLY (PIVOT PIN 523.10.12.210) HAD SHEARED. THE SHEARED AN4-27 BOLT ALLOWED THE PIN TO ROTATE FREELY IN THE TRAILING LINK, THIS CAUSED THE WOW PROXIMETY SWITCH TO MALFUNCTION DUE TO THE PROXIMITY TARGET BEING MOVED FROM SET POSITION.

UPON START PILOT HEARD HIGH PITCH HOWLING NOISE EMANATING FROM ENGINE/EXHAUST AREA. PILOT ELECTED TO SHUTDOWN TO NOTIFY MAINTENANCE. UPON RECEIPT, PHI CONDUCTED A BORESCOPE INSPECTION AND NOTED DAMAGE ON THE 1ST STAGE TURBINE WHEEL. THE 1ST STAGE TURBINE WHEEL, NOZZLE, & 2ND STAGE TURBINE NOZZLE WERE SUBMITTED TO THE MATERIALS LAB IN INDIANAPOLIS, IN FOR ANALYSIS. THE PRIMARY FINDINGS OF THE METALLURGICAL INVESTIGATION. A SINGLE FIRST STAGE TURBINE WHEEL AIRFOIL FRACTURED AND LIBERATED IN HIGH CYCLE FATIGUE (HCF). A SPHERICAL GAS HOLE APPROXIMATELY 0.009 INCH IN DIAMETER OBSERVED AT THE ORIGIN AREA. THE OVERALL COMPOSITION AND MICROSTRUCTURE OF THE FIRST STAGE TURBINE WHEEL MET THE COMPONENT DEFINITION REQUIREMENTS. OVERALL VIEWS OF THE FIRST STAGE TURBINE WHEEL IN THE AS-RECEIVED CONDITION ARE SHOWN IN FIGURE 1 (LEFT). THE FRACTURED AIRFOIL IS LABELED AS NR 1. 30 AIRFOILS EXHIBITED DAMAGE ON THE TRAILING HALF OF THE AIRFOILS, CONSISTENT WITH SECONDARY DAMAGE THAT OCCURRED AFTER THE LIBERATION OF AIRFOIL #1. A DETAILED VIEW OF AIRFOIL SURFACE IS SHOWN IN FIGURE 1 (RIGHT), EXHIBITING RADIATING LINES AND BEACH MARKS CONSISTENT WITH FATIGUE PROGRESSION OUTWARD FROM THE FRACTURE ORIGIN (ORANGE BORDER, AT THE SUCTION SIDE CROWN ROOT AREA AS SHOWN IN THE BLACK ARROWS) THEN TRANSITIONS TO OVERLOAD, INDICATED BY THE YELLOW DASHED LINES. THE FRACTURE ORIGIN WAS VISUALLY CONSISTENT WITH HIGH CYCLE FATIGUE INITIATION.FIGURE 1, TURBINE WHEEL AS RECEIVED (LEFT). DETAILED VIEW OF AIRFOIL NR 1 FRACTURE SURFACE (RIGHT) JURISDICTION EXPORT CONTROL CLASSIFICATION (RATING) USE OR DISCLOSURE OF THIS DATA IS SUBJECT TO THE RESTRICTION ON THE FIRST PAGE OF THIS DOCUMENT. AIRFOIL #1 WAS EXTRACTED FROM THE WHEEL AND THE FRACTURE SURFACE SUBJECTED TO SCANNING ELECTRON MICROSCOPIC (SEM) EXAMINATION. DETAILED IMAGES OF THE ORIGIN AREA AND FATIGUE REGION ARE SHOWN IN FIGURE 2. THE ORANGE ARROWS INDICATE DIRECTION OF FATIGUE PROGRESSION; THE DASHED YELLOW BORDER INDICATES THE FATIGUE FACETS. THE SOLID YELLOW BORDER INDICATES THE GAS HOLE AT THE ORIGIN. A PORE CONSISTENT WITH A GAS HOLE WAS LOCATED AT THE FATIGUE ORIGIN. THE GAS HOLE WAS APPROXIMATELY 0.009 INCH IN DIAMETER AND LOCATED APPROXIMATELY 0.009 INCHES FROM THE SUCTION SIDE OF THE AIRFOIL. FIGURE 2: DETAILED SEM IMAGES, ORIGIN LOCATION CONCLUSION BASED ON COMPREHENSIVE LABORATORY ANALYSIS, IT IS CONCLUDED THAT THE MOST PROBABLE CAUSE OF THE BLADE LIBERATION WAS THE PRESENCE OF A SPHERICAL GAS PORE LOCATED IN THE CROWN ROOT OF THE AIRFOIL. THIS SUBSURFACE GAS PORE SERVED AS THE INITIATION SITE FOR FATIGUE CRACKING, ULTIMATELY LEADING TO CRACK PROPAGATION AND OVERLOAD FRACTURE OF THE AFFECTED AIRFOIL. THE M250 FAMILY OF STAGE 1 TURBINE BLISKS, INCLUDING THE SUBJECT PART (PN M250-10226), ARE MANUFACTURED USING A CENTER-OUTWARD CASTING PROCESS. THIS METHOD IS CONSISTENT WITH AEROSPACE INDUSTRY STANDARDS & IS SPECIFICALLY DESIGNED TO DRIVE RESIDUAL CONTAMINANTS AND CASTING ANOMALIES TOWARD THE OUTER DIAMETER, THEREBY MINIMIZING THE RISK OF SUCH DEFECTS IN CRITICAL BORE REGIONS. A THOROUGH REVIEW OF THE FIXED MANUFACTURING PROCESS REVEALED NO SYSTEMATIC ISSUES. ALL PARTS UNDERGO RIGOROUS VISUAL, DIMENSIONAL, FLUORESCENT PENETRANT, AND X-RAY INSPECTIONS. ADDITIONALLY, A LEVEL III NDT-CERTIFIED SPECIALIST IS CURRENTLY RE-EXAMINING THE HISTORICAL X-RAY RECORDS FOR THIS COMPONENT AT THE CASTING FACILITY. A REVIEW OF HISTORICAL DATA FOUND NO EVIDENCE OF SIMILAR OCCURRENCES IN STAGE 1 BLISKS. GIVEN THAT THE GAS PORE IS ASSESSED TO BE AN ISOLATED, RANDOM ANOMALY, NO FLEETWIDE ACTIONS ARE RECOMMENDED AT THIS TIME.

TAIL ROTOR BLADE CONTROL PITCH LINK BEARING FAILED, THE INNER RACE SEPARATED FROM THE OUTER RACE, WHICH ALLOWED THE PITCH LINK ROD END TO MOVE AXIALLY ALONG THE ATTACHMENT HARDWARE WITHIN THE FORK OF THE TAIL ROTOR BLADE PITCH CONTROL FITTING.

DURING POST FLIGHT PILOT WALK AROUND, NOTED UPPER CAP OF VERTICAL STABILIZER DEPARTED IN FLIGHT. EXPOSED WIRING WAS VISIBLE.

UPON DISASSEMBLY OF ENGINE FOR 2000HR INSPECTION TECHNICIAN FOUND #2 BEARING RETAINER NUT TO BE LOOSE. REMOVED IT BY HAND.

IN FLIGHT, SMOKE ACCUMULATED IN THE CABIN COMING FROM THE HEATING SYSTEM. PILOT TURNED OFF THE HEATING SYSTEM AND SMOKE DISSIPATED. UPON LANDING, IT WAS FOUND #1 BEARING WAS LEAKING AROUND THE SEAL RESULTING IN THE SMOKE IN THE BLEED AIR SYSTEM.

CLIMBING OUT OF BOI, CREW NOTICED ODD SMELL IN THE BACK OF THE AIRCRAFT AND PILOT RETURNED TO BOI. SUSPECT COCKPIT MIXING VALVE FAILURE BUT SUPPLEMENTAL INFORMATION TO FOLLOW ONCE AN ACTION TO REPAIR HAS BEEN TAKEN AND IS CONFIRMED.

UPON MAINTENANCE INVESTIGATION IT WAS FOUND THAT THE ENGINE DEICE INLET LIP WAS CRACKED.

PASSING 11K ALT PLANE STARTED MAKING A HISSING SOUND BEHIND ME BUT IN FRONT OF THE MED CREW. PASSING 5K ALT. THE MED CREW STARTED TO SMELL FUMES. ON SHORT FINAL I SMELLED WHAT I WOULD EXPLAIN AS BURNING DE-ICE. NO CASS MESSAGES OR ABNORMAL ENGINE INDICATION WERE OBSERVED. SHUT DOWN ON THE TAXI WAY TO EVACUATE AIRCRAFT. NO FINDINGS TO EXPLAIN THE ODOR. POSSIBLE DE-ICE LIP LEAK

FOUND LANDING GEAR SADDLE CRACKED

SMOKE IN CABIN WHEN HEAT IS TURNED ON. FOUND ENGINE #1 BEARING CARBON SEAL LEAKING CAUSING CONTAMINATION OF BLEED AIR. DELAYED SUBMITTAL DUE TO INABILITY TO ACCESS SYSTEM

WE HAD JUST COMPLETING OEI TRAINING WITH THE TRAINING MODE ON THE NUMBER ONE ENGINE. AFTER COMPLETING OUR OEI TRAINING, ROGER PLACED THE TRAINING MODE BACK TO CENTER POSITION AND ALL INDICATIONS ON THE NUMBER ONE ENGINE WERE NORMAL. I PLACE THE RPM SWITCH BACK TO 102% AND PREPARED FOR TAKEOFF. AFTER TAKEOFF AT ABOUT 500’ AND ABOUT 70 KNOTS WE STARTED TO NOTICE A FUEL SMELL AND WITHIN A FEW SECONDS WE GOT INDICATIONS OF A NUMBER ONE ENGINE FAILURE. WE BRIEFLY TRIED TO DIAGNOSE THE PROBLEM WHILE I TURNED BACK TOWARDS THE AIRFIELD FOR A LANDING. WE BOTH CONFIRMED THAT THE TRAINING SWITCH HAD NOT BEEN MOVED SO I CONTINUED BACK TO THE AIRPORT AND LANDED RUNWAY 12. WE PERFORMED A ROLL ON LANDING AND CONTINUED TO ROLL TO THE FBO AND PERFORMED A SHUTDOWN AFTER PARKING. I PLACED ENGINE SWITCHES TO IDLE AND NOTICED THE TOT REMAINED AT ABOUT 450 ON THE NUMBER ONE ENGINE SO ROGER PULLED THE IGN CB IN CASE WE WANTED TO MOTOR THE STARTER. WE DETERMINED THAT MOTORING THE STARTER WAS NOT NEEDED AND SHUT DOWN THE NUMBER 2 ENGINE NORMALLY AND SWITCHED OFF THE NUMBER ONE ENGINE CONTROL KNOB AS WELL. AFTER SHUTDOWN A BRIEF INSPECTION OF THE NUMBER ONE ENGINE REVEALED FUEL ON THE ENGINE DECK AND THE FUEL MANIFOLD (FLOW DIVIDER) ON THE BOTTOM OF THE ENGINE WAS LOOSE, CAUSING THE FUEL TO NOT MAKE IT TO THE ENGINE AND IT FLAMED OUT.

SUSPECTED CRACK IN PROPELLER DRIVE FLANGE CAUSING FLUID LOSS.

DURING INSPECTION, LAG DAMPER UPPER INBOARD ATTACHMENT HOUSING FOUND CRACKED ALL THE WAY THROUGH.

MAIN GEAR BOX TRANSMISSION LIGHT IN FLIGHT. GEAR BOX REQUIRED REPLACEMENT DUE TO CHIP MATERIAL. THIS IS THE THIRD CHIP EVENT ON THE MGB, TWO PREVIOUS INSTANCES WERE ON 11/14/2019 ON MGB SN V3 (TT 2483.1) AND ON 10/18/2019 MGB SN V75 (TT:3182.8).

HYDRAULIC CAS MESSAGE ON APPROACH. NOSE LANDING GEAR HAD TO BE HAND PUMPED TO THE DOWN AND LOCKED POSITION. MAIN HYDRAULIC POWER RELAY (K161) P/N 974.09.26.112 WAS FOUND TO BE IN-OP, AND GROUND (GB501) WAS FOUND TO BE CORRODED.

DURING CLIMB, OIL SPLATTERED ON WINDSHIELD. PILOT RETURNED TO HIS DEPARTURE AIRPORT AND LANDED. UPON INVESTIGATION, IT WAS FOUND THAT THE PROP BETA SEAL WAS LEAKING DURING FULL POWER RUNS BUT NOT AT IDLE. PROPELLER WAS REMOVED AND REPLACED WITH A SERVICEABLE PROPELLER.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT HAND PLATE FITTING CRACKED.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT PLATE FITTING CRACKED.

DURING 2400 HOUR INSPECTION, NDT (FLUORESCENT PENETRATION) PERFORMED ON SWASH-PLATE FIXED ASSEMBLY WHERE INDICATIONS OF CRACKS WERE PRESENT IN THE RECESS WHERE THE DUPLEX BEARING SITS. NDT WAS PERFORMED A SECOND TIME WITH THE INDICATIONS STILL VISIBLE. SWASH-PLATE HAS BEEN RETURNED TO FOR FURTHER EVALUATION TO CONFIRM CRACKS.

DURING INSPECTION FOUND MAIN TRANSMISSION LEFT PLATE FITTING CRACKED.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT HAND PLATE FITTING CRACKED.

DURING INSPECTION, FOUND MAIN TRANSMISSION AFT RIGHT PLATE FITTING CRACKED.

DURING INSPECTION, FOUND MAIN TRANSMISSION AFT RIGHT PLATE FITTING CRACKED.

DURING A MAINTENANCE FLIGHT, MAIN GEAR BOX CHIP ILLUMINATED. AIRCRAFT RETURNED TO ORIGINAL DEPARTURE WITHOUT FURTHER INCIDENT. MAIN GEARBOX HAD .2 HOURS SINCE REPAIR.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT PLATE FITTING CRACKED.

DURING INSPECTION, FOUND MAIN TRANSMISSION AFT RIGHT PLATE FITTING CRACKED.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT PLATE FITTING CRACKED

DURING INSPECTION, FOUND THE MAIN TRANSMISSION AFT RIGHT PLATE FITTING CRACKED.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT PLATE FITTING CRACKED.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT PLATE FITTING CRACKED.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT PLATE FITTING CRACKED.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT PLATE FITTING CRACKED.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT HAND PLATE FITTING CRACKED.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT HAND PLATE FITTING CRACKED.

FORKED END OF HOUSING HAS A CRACK PROPAGATING FROM ONE SIDE OF THE BUSHING BORE AROUND THE OPPOSITE SIDE OF THE BORE.

DURING INSPECTION FOUND MAIN TRANSMISSION AFT RIGHT HAND PLATE FITTING CRACKED.

DURING CLIMB, PILOT NOTICED BINDING IN AILERON CONTROLS. RETURNED TO DEPARTING AIRPORT. UPON INSPECTION FOUND RT AILERON BELL CRANK BEARING WAS FULL OF WATER. SUSPECTED WATER FROZE AT ALTITUDE AND CAUSED BINDING.

DURING CRUISE FLIGHT, ABNORMAL ITT INDICATIONS STARTED TO OCCUR. ATTEMPTED TO TROUBLESHOOT, BUT ENGINE ITT WAS EXCEEDING LIMITATIONS ALLOWED. AIRCRAFT DECLARED EMERGENCY AND LANDED WITHOUT FURTHER PROBLEMS.

DURING CLOSING OF THE LEFT HAND PASSENGER SLIDING DOOR, REAR GUIDE PIN WAS PULLED FROM STRUCTURE CAUSING DAMAGE. DAMAGE WAS DUE TO MISALIGNMENT OF DOOR AND WHEN CLOSED DID NOT CONTACT THE AIRCRAFT STRUCTURE IN THE CORRECT MANNER. DOOR POST REPAIRED.

DISCOVERED CRACK IN LE CAP OF TAIL ROTOR BLADE, APPROX CRACK IS 7MM IN LENGTH, STARTING 2MM FROM TIP END OF LE CAP, CRACK CONFIRMED USING DYE PENETRANT METHOD. ACFT TAKEN OUT OF SERVICE UNTIL REPLACEMENT PARTS COULD BE INSTALLED. ROTOR BLADE CAME NEW WITH ACFT, CURRENT TSN = 65.8HRS, LANDING CYCLES = 116, TR BLADE LIFE LIMIT IS 10,000 LANDINGS.