N812MH

ATA 7200

PRIOR TO OPS CHECK, FLIGHT TAKEOFF ENGINE CHIP LIGHT ILLUMINATED. FLIGHT WAS ABORTED. ALL DEFECTIVE INSPECTED AND METAL RECEIVED. RUNS COMPLETED. NO LIGHT . EVEN THOUGH FOLLOWING SUCCESSFUL PENALTY RUNS AND NO LIGHT AFTER 1.5 HOURS OF FLIGHT CHECK IT WAS APPARENT THAT METAL WAS CONTINUED TO BE GENERATED. METAL ON MODULE 5 CHIP DETECTOR AND PICKUPS FOUND MODULE 5 REPLACED. NO FURTHER DEFECT NOTED. METAL GENERATION SO SHORTLY AFTER OVERHAUL IS A BIT UNUSUAL BUT WITH THIS MODULE, MAKING METAL IS EASILY IDENTIFIED BY METAL COLLECTING ON THE HIGHLY MAGNETIC PICKUPS AS WELL AS THE CHIP DETECTOR. (K)

ATA 5302

CRACK DISCOVERED DURING ROUTINE INSPECTION ON FITTING FLANGE AND GOING THROUGH AN ATTACHMENT BORE. A NEW FITTING WAS MATCH DRILLED AND INSTALLED. THIS IS A VERY COMMON PROBLEM FOR THIS PART. SUGGEST THIS PART BE MANUFACTURED FROM A MORE DURABLE MATERIAL SUCH AS TITANIUM OR STAINLESS STEEL. (K)

ATA 7200

SHORTLY AFTER ENGINE OVERHAUL WAS COMPLETED AND ENGINE RETURNED TO FLIGHT STATUS THE POWERSHAFT SEAL BEGAN TO WEEP AND PROGRESSIVELY THE WEEP BECAME A LEAK. A NEW SEAL WAS INSTALLED AND NO FURTHER LEAKAGE WAS NOTED. SUGGEST IMPROVED QUALITY CONTROL FOR THESE SEALS BEFORE INSTALLATION MAY BE REQUIRED. (K)

ATA 6700

PILOT REPORTS HAVING AN AMBER GOVERNOR LIGHT IN FLIGHT. UPON AC SHUTDOWN, A FAILURE CODE WAS GENERATED INDICATING THE COLLECTIVE POTENTIOMETER WAS DEFECTIVE. A NEW PART WAS INSTALLED WITH NO FURTHER DEFECT REPORTED. THIS IS A RECURRING PROBLEM FOR THIS PART THAT HAS EFFECTED THE DISPATCH RELIABILITY FOR THIS MODEL AIRCRAFT. AS THIS DESIGN HAS SUCH A HIGH FAILURE RATE PERHAPS AN OPTIC DESIGN WITH NO CONTACT WITH A RESISTANCE RIBBON AS WITH THE CURRENT DESIGN SHOULD BE CONSIDERED. (K)

ATA 8000

FOUND CRACKED DURING ROUTINE 100 HOUR INSPECTION. THIS IS A VERY COMMON PROBLEM FOR THIS PART. SUGGEST A MORE ROBUST MATERIAL SUCH AS SS BE UTILIZED TO REDUCE THE CRACKING OR PERHAPS A MACHINED PART. (K)

ATA 5302

CRACK FOUND DURING ROUTINE INSPECTION RADIATING FROM A SCREW HOLE TO THE EDGE OF THE MACHINED FLANGE. A NEW FITTING WAS MATCH DRILLED AND INSTALLED. (K)

ATA 5302

CRACK FOUND DURING ROUTINE INSP RADIATING FROM A SCREW HOLE ON MOUNTING FLANGE SURFACE AND ONTO REINFORCEMENT RIB SURFACE. A NEW FITTING HAS BEEN MATCH DRILLED AND INSTALLED. (K)

ATA 3150

PILOT REPORTS AMBER GOVERNOR LIGHT CAME ON IN FLIGHT. NO FAULT CODE WAS GENERATED INDICATING A POTENTIOMETER DEFECT HOWEVER CIRCUMSTANCES REPORTED POINTED TO THIS. A NEW POTENTIOMETER HAS BEEN INSTALLED. PROBLEM FIXED THIS PART HAS LASTED MUCH LONGER THAN TYPICAL THIS IS A RECURRING PROBLEM FOR THIS PART THAT HAS EFFECTED THE DISPATCH RELIABILITY OF THIS MODE AC. THIS PART CAN ON OCCASION ALSO CAUSE ENGINE FLUCTUATIONS IN FLIGHT WHEN THE RESISTANCE VALUE SIGNAL IS DISRUPTED FOR A LITTLE AS 1/20TH OF A SECOND, WHICH IS THE SAMPLE RATE FOR THE ENGINE CONTROL SYS. AN ADDITIONAL FACTOR FOR THESE TYPE OF FAULTS IS NO RESET FUNCTION AVAILABLE TO THE PILOT TO DIFFERENTIATE BETWEEN A MOMENTARY OR AN ACTIVE FAULT. ONCE THE AMBER WARNING LIGHT IS ILLUMINATED IT REMAINS ON UNTIL THE FLIGHT IS TERMINATED EVEN IF SIGNAL DISRUPTION WAS ONLY FOR 1/20TH OF A SECOND DURING AN IN-FLIGHT TURBULENCE EVENT. (K)

ATA 6200

THIS PART WAS FOUND CRACKED DURING ROUTINE INSPECTION. THE CRACK ALWAYS OCCURS IN THE RADIUS OF THE LOWER IB CORNER FLANGE ALMOST ALL OF THESE SPRING COVERS WILL REQUIRE REPLACEMENT MULTIPLE TIMES WITHIN THE FIRST FEW THOUSAND FLIGHT HOURS OF THE AIRCRAFT. THE MFG HAS BEEN ASKED TO CHANGE THE DESIGN OR MATERIAL TO CORRECT THIS REPETITIVE CRACK PROBLEM BUT NO ACTION OTHER THAN MAKING THE PART PROCURABLE AS A SUBASSEMBLY OF THE AVA LOWER FLANGE ASSY HAD BEEN TAKEN BY THE MFG. (K)

ATA 5200

DURING ROUTINE INSPECTION IT WAS NOTED THAT THE TOP OF THE FLAP DOOR WAS EXCESSIVELY LOOSE. CLOSER INSPECTION REVEALED THAT THE DOOR’S ATTACHMENT HARDWARE HAD LOOSENED ALLOWING THE FITTING TO WEAR AROUND THE SCREW AND ULTIMATELY BREAK THROUGH THE METAL FLANGE EDGE. A SERVICEABLE PART WAS INSTALLED. RECOMMEND THAT ALL HARDWARE BE CHECKED FOR PROPER TORQUE ON ALL THE DOOR FITTING AS JUST A VISUAL CHECK MAY NOT REVEAL THIS PROBLEM DEVELOPING BEFORE PARTS ARE DAMAGED. PART WAS MADE OF ALUMINUM AND SUGGEST THAT IT BE MADE WITH SS TO BE MORE DURABLE. (K)

ATA 6220

DURING SCHEDULED MAINT ONE ADAPTER OF SET OF 3 FOUND TO HAVE INTERNAL/EXTERNAL ELASTOMER CRACK EXCEEDING MM LIMITATIONS OF 10MM. THIS IS A VERY COMMON FAILURE THAT OCCURS AT HALF OR LESS OF THIS PARTS SERVICE LIFE LIMIT OF 3000 HOURS. THE OLDER PN ADAPTERS USED A DIFFERENT ELASTOMER FORMULATION THAT ALMOST ALWAYS LASTED 3000+ HOURS. SUGGEST THIS FORMULATION AGAIN BE USED. (K)

ATA 7261

ENGINE OIL VENT TUBE, AIRFRAME PART, MOUNTED ON ENG WITH VENTING ORIFICE PLACED IN EXHAUST PATH HAS ANTI-ROTATION CLAMP WELDED TO STAINLESS TUBE BODY, CRACKS INITIATE IN SPOT WELDS CAUSING CLAMP FLANGE TO CRACK. REPAIR, DRESSING OFF FLANGE REMNANTS, INSTALLING A HIGH TEMP FITTED CLAMP HAS BEEN RECOMMENDED BY AC MFG ENGINEERING DEPART. TUBES NOW HAVE CRACKS DEVELOPING AROUND TUBE CIRCUM EMANATING FROM CLAMP SPOT WELDS. THESE TUBES HAVE BEEN REMOVED AND REPLACED. UNDISCOVERED CRACK AT TUBE SECTION COULD LEAD TO 10 IN LONG, .6250 IN DIA PIECE OF TUBE DEPARTING THE AC, POSSIBLY STRIKING MAIN ROTOR BLADES OR TAIL ROTOR BLADES. RECOMMEND NEW TUBES W/O WELDED CLAMPS, THAT ARE HELD WITH HIGH TEMP CLAMPS.