N804MH

ATA 3150

Part: POTENTIOMETER — DEFECTIVE (WARNING LIGHT)

PILOT REPORTS AMBER GOVERNOR LIGHT ILLUMINATED DURING FLIGHT. A FAULT CODE WAS GENERATED INDICATING THE POTENTIOMETER AS THE LIKELY DEFECTIVE UNIT. A NEW PART WAS INSTALLED AND NO FURTHER DEFECTS WERE NOTED. THIS IS A RECURRING PROBLEM FOR THIS PART THAT HAS EFFECTED THE DISPATCH RELIABILITY FOR THIS AC MODEL. (K)

ATA 5100

Part: FITTING — CRACKED (UNKNOWN)

PART FOUND CRACKED DURING ROUTINE INSP IAW AD2004-01-14/SB53A004 REQUIREMENTS AT THE 110 HOURS INTERVAL INSPECTION. A NEW PART OF THE OLD PN WAS INSTALLED. SUGGEST MFG MAKE AVAILABLE THE NEW PN IMPROVED FITTING THAT DO NOT HAVE THE AD REQUIREMENT TO ALL EC130B4 OPERATORS AS SOON AS POSSIBLE. (K)

ATA 3150

Part: POTENTIOMETER — DEFECTIVE (WARNING LIGHT)

PILOT REPORTS AMBER GOVERNOR LIGHT ILLUMINATED DURING FLIGHT. A FAULT CODE WAS GENERATED INDICATING THE POTENTIOMETER AS THE LIKELY DEFECTIVE UNIT. A NEW PART WAS INSTALLED AND NO FURTHER DEFECTS WERE NOTED. THIS IS A RECURRING PROBLEM FOR THIS PART THAT HAS EFFECTED THE DISPATCH RELIABILITY FOR THIS AC MODEL. (K)

ATA 6700

Part: POTENTIOMETER — INTERMITTENT (COLLECTIVE)

THIS PART IS THE POSITION INDICATOR FOR BOTH COLLECTIVE AND TAIL ROTOR FADEC CONTROL ACTIONS. IT ALMOST NEVER FAILS TOTALLY BUT GENERATES A FAILURE CODE THAT REQUIRES THEY BE REPLACED. THESE PARTS CAN LAST THOUSANDS OF HOURS OR LESS THAN FIFTY. ONLY RECENTLY DID THE AIRCRAFT MFG MAKE THIS A TIME CHANGE ITEM AND UP TO THAT POINT THEY VERY RARELY HAD A PROBLEM. DUE TO THE WEEKLY FAILURE OF ONE OF THESE POTENTIOMETERS IN OUR FLEET WHICH WE NEVER EXPERIENCED BEFORE REPLACING THE ORIGINAL PARTS ON OUR OLDER AC AND THE FACT THAT AC DELIVERED ABOUT THE SAME TIME AS THE NEW REPLACEMENT PARTS WERE BEING INSTALLED IN OUR FLEET BEGAN HAVING RELIABILITY PROBLEMS WE ARE SURE THAT A QC ISSUE EXISTS. (K)

ATA 6700

Part: POTENTIOMETER — INTERMITTENT (COLLECTIVE)

THIS PART IS THE POSITION INDICATOR FOR BOTH COLLECTIVE AND TAIL ROTOR FADEC CONTROL ACTIONS. IT ALMOST NEVER FAILS TOTALLY BUT GENERATES A FAILURE CODE THAT REQUIRES THEY BE REPLACED. THESE PARTS CAN LAST THOUSANDS OF HOURS OR LESS THAN FIFTY. ONLY RECENTLY DID THE AIRCRAFT MFG MAKE THIS A TIME CHANGE ITEM AND UP TO THAT POINT THEY VERY RARELY HAD A PROBLEM. DUE TO THE WEEKLY FAILURE OF ONE OF THESE POTENTIOMETERS IN OUR FLEET WHICH WE NEVER EXPERIENCED BEFORE REPLACING THE ORIGINAL PARTS ON OUR OLDER AC AND THE FACT THAT AC DELIVERED ABOUT THE SAME TIME AS THE NEW REPLACEMENT PARTS WERE BEING INSTALLED IN OUR FLEET BEGAN HAVING RELIABILITY PROBLEMS WE ARE SURE THAT A QC ISSUE EXISTS. (K)

ATA 7230

Part: BEARING — SEIZED (IMPELLER)

PILOT WAS IN A HOVER TAXI WHEN AN UNUSUAL HIGH FREQUENCY VIBRATION WAS FELT IN THE AC AND PARTIAL POWER LOSS BECAME APPARENT AND AC WAS LANDED WITH A CHIP LIGHT ILLUMINATING WITHIN SECONDS OF GROUND CONTACT AND ENGINE WAS SHUTDOWN. A VERY RAPID DECAY OF NG SPEED WAS NOTED. EXAMINATION OF ENGINE REVEALED THAT COMPRESSOR WAS LOCKED UP AND WHEN VIEWING INTO THE BLEEDVALVE SCREEN THE CENTRIFUGAL IMPELLER SHROUD HAD BEEN PENETRATED BY THE IMPELLER AND SOME SMALL PIECES HAD BEEN EJECTED FROM THE BLEED VALVE PORT AND WERE ON THE ENGINE DECK. MODULE 1 AND THE ENGINE ELECTRICAL CHIP DETECTOR PLUGS HAD A GENEROUS AMOUNT OF METAL ON THEM. A PREVIOUS LIKE FAILURE HAD BEEN DETERMINED TO BE THE BEARING JUST FWD OF THE CENTRIFUGAL COMPRESSOR STAGE HAD FAILED. OUR EXPERIENCE HAS BEEN OF 2 SUCH FAILURES DURING 50,000 HOURS WE HAVE OPERATED THIS MODEL ENGINE. THIS DESIGN HAS BEEN RELIABLE AND UNCHANGED FOR MILLIONS OF FLIGHT HOURS IN THESE SERIES ENGINES. A QUALITY ISSUE? (K)

ATA 3300

Part: LIGHT — UNKNOWN

THIS LIGHT ASSY HAS BEEN FAIRLY RELIABLE BUT IS A LITTLE DIFFICULT TO WORK ON REQUIRING PIN EXTRACTION TOOLING TO TROUBLESHOOT OR REPLACE. THE TYPICAL FAILURE IS INSIDE THE SEALED UNIT. THE QUALITY OF CONSTRUCTION IS EXCELLENT. (K)

ATA 7320

Part: HMU — FAILED (ENGINE)

AFTER TAKEOFF, AC CWP RED AND YELLOW GOVERNOR LIGHT SEGMENTS ILLUMINATED, IT BECAME APPARENT BY ENG INDICATIONS THAT EMERGENCY BACKUP CONTROL UNIT HAD TAKEN CONTROL OF ENG. PILOT ELECTED TO LAND AC AT FIRST SUITABLE LANDING SITE. VEMD INDICATED A FAULT WAS DETECTED WITH PUMP AND ADJUSTED VALVE METERING UNIT (HMU). METERING VALVE CONTROL STEPPER MOTOR APPEARED TO WORK NORMALLY SO IT IS ASSUMED THAT INTERNAL PRESSURE REGULATING DIAPHRAGM RUPTURED. A SERVICEABLE HMU WAS INSTALLED, SUBSEQUENT TESTS VERIFIED DEFECT CORRECTED AND AC RETURNED TO BASE. THIS WOULD BE SECOND INSTANCE KNOWN OF SUCH A RUPTURE, EACH CASE CONTROL HAD APPROX 2500 HOURS TIME IN SERVICE. RETURNED TO OEM FOR EVALUATION AND REPAIR. (K)

ATA 2913

Part: PUMP — INOPERATIVE (HYDRAULIC SYS)

DURING RUNUP, IT WAS NOTICED THAT HYDRAULIC PRESSURE WARNING FAILED TO EXTINGUISH UNTIL AIRCRAFT WAS RUN-UP ABOVE IDLE TO FLIGHT IDLE SPEED. SUBSEQUENT INVESTIGATION REVEALED NO FLUID RETURN TO THIS PUMPS RESERVOIR. REPLACEMENT OF THE PUMP CORRECTED THE PROBLEM. EXTERNALLY THE REMOVED PUMP APPEARED NORMAL. PUMP RETURNED TO MFG FOR INSPECTION. THIS IS A 2-PUMP HYDRAULIC SYSTEM. (K)