N807MH

ATA 6320

OIL PRESSURE LIGHT ILLUMINATES AT GROUND IDLE. NEW SWITCH NORMALLY WORKS WELL BUT ON OCCASION LOSES INTERNAL CALIBRATION OR IS MISCALIBRATED AS NEW SWITCHES SOMETIMES EXHIBIT THE SAME PROBLEM. SUGGEST A MORE MODERN DESIGN BE CONSIDERED FOR THIS PART. (K)

ATA 6720

UPON SHUTDOWN A FAULT CODE WAS GENERATED THAT INDICATED A FAULT WITH COLLECTIVE POTENTIOMETER. A NEW POTENTIOMETER WAS INSTALLED AND NO FURTHER DEFECT NOTED. THIS HAS BEEN A VERY COMMON FAULT FOR THIS PART. RECENTLY IT WAS DETERMINED THAT ELECTRICAL HARNESS FOR THIS SIGNAL WAS LACKING SHIELDING, ADJACENT WIRING MAY HAVE BEEN INDUCING SOME SPURIOUS INPUTS TO FADEC THAT WERE INTERPRETED AS A FAULT. RE-ROUTED OUR AIR CONDITIONING WIRE HARNESS TO INCLUDE SPACERS SO AS TO REDUCE CHANCE OF SIGNAL CORRUPTION, OCCURRENCES OF THIS FAILURE TYPE HAVE BEEN SIGNIFICANTLY REDUCED. THIS MAY BE A COINCIDENCE BUT A CASE IS BUILDING TO USE SHIELDED HARNESS TO CARRY THIS RESISTANCE SIGNAL TO FADEC. (K)

ATA 7410

DURING ROUTINE INSPECTION AN OPERATIONAL CHECK REVEALED VERY SLOW FUNCTION ON (1) OF THE (2) IGNITERS POWER CIRCUITS. A NEW IGNITER BOX WAS INSTALLED AND OPERATIONAL CHECK WAS NORMAL. THIS PARTIAL LOSS OF A CIRCUIT IS TYPICAL FOR THIS ASSEMBLY. USUALLY THIS UNIT IS TROUBLE FREE.

ATA 6320

LOW MGB OIL PRESSURE WARNING LIGHT FLICKERED IN FLIGHT WITH NO AUDIBLE WARNING. SWITCH WAS REPLACED WITH A SERVICEABLE PAR AND WITH NO FURTHER DISCREPANCY NOTED. THIS IS TO AN UNCOMMON FAULT FOR THIS PART. SUGGEST IMPROVED DESIGN OR BETTER QC FOR INTERNAL PARTS AS PERHAPS ONLY A THIRD OF THESE SWITCHES FAIL IN SERVICE. (K)

ATA 6710

A FAULT CODE WAS GENERATED ON SHUTDOWN INDICATING A DEFECT OF COLLECTIVE POTENTIOMETER. A NEW PART WAS INSTALLED, NO FURTHER FAULT WAS DETECTED. THIS IS RECURRING FAILURE FOR THIS PART WHICH HAS EFFECTED DISPATCH RELIABILITY FOR THIS MODEL HELICOPTER. SUGGEST AN ALTERATION OF FAULT SENSING SOFTWARE TO REDUCE FAULT SENSITIVITY TO PERHAPS A SIGNAL LOSS OF 0.5 SECOND RATHER THAN 1/20TH OF A SECOND. AN OPTIC RATHER THAN A RESISTANCE BASED SENSOR SHOULD BE CONSIDERED AS CONTACT POINT IS DAMAGED BY AC VIBRATION WHEN AC POWER SETTINGS ARE SET FOR CRUISE FLIGHT. (K)

ATA 5302

DURING ROUTINE INSPECTION A CRACK WAS DISCOVERED THROUGH THE STRENGTHENING RIB OF THE MOUNTING FLANGE. CRACK DEVELOPMENT IS A VERY COMMON FAILURE FOR THIS PART. SUGGEST A MORE ROBUST MATERIAL SUCH AS SS OR TITANIUM BE UTILIZED. (K)

ATA 6220

DURING ROUTINE INSP A CRACK IN THE YELLOW BLADES FREQUENCY ADAPTER WAS FOUND TO EXCEED THE MM 10MM LIMITATION, CRACK WAS FOUND ON THE T/E SIDE OF THE ADAPTER. (K)

ATA 3150

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 5350

DURING ROUTINE 100 HOUR INSPECTION, A CRACK WAS FOUND RADIATING ACROSS THE CORNER OF THE FIRST HOLE ON THE HINGE END WITH A TOTAL SEPARATION OF THE HINGE CORNER METAL ON THE FAIRING ATTACHMENT FLANGE. A NEW PART WAS INSTALLED IAW THE REQUIREMENTS OF AD2004-01-14 AN INSPECTION DUE AT 110 HOUR INTERVAL. THIS IS A FAIRLY COMMON DEFECT FOR THIS PART. SUGGEST THE NEW IMPROVED PN ASSY BE MADE IN QUANTITIES SO ALL AC MAY BE UPDATED TO THE LATEST NON AD EFFECTED PN. THIS IS A MFG SUPPLY ISSUE THAT THE OEM REFUSES TO ADDRESS. (K)

ATA 6320

PILOT REPORTED THAT THE MAIN GEARBOX LOW OIL PRESSURE WARNING LIGHT ILLUMINATED INTERMITTENTLY AT IDLE. A NEW OIL PRESSURE TRANSMITTER WAS INSTALLED AND NO FURTHER FALSE INDICATIONS NOTED. THIS SWITCH HAS A MODERATE FAILURE RATE USUALLY BY LOSING ITS LOW END CALIBRATION AND ILLUMINATING WHEN AC IS IDLING. SUGGEST A DESIGN UPDATE IS REQUIRED TO IMPROVE THIS TRANSMITTERS RELIABILITY. (K)

ATA 3300

AT FULL BRIGHTNESS ADJUSTMENT ALL CONTROLLED LIGHTING FLICKERS ON AND OFF INTERMITTENTLY. REPLACEMENT WITH NEW PART CORRECTED THE DEFECT. (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 5210

UPON LANDING PILOT FOUND HANDLE TO BE LIMP AND FLOPPING IN THE SLIPSTREAM. DOOR HAD TO BE OPENED UTILIZING THE INSIDE HANDLE. BELLCRANK LEVER WHICH CONNECTED OUTSIDE HANDLE TO THE DOOR LATCHING MECHANISM HAD BROKEN. A NEW DOOR HANDLE ASSY WAS INSTALLED. (K)

ATA 8000

PILOT REPORTED THAT SEVERAL SELECTIONS TO THE ENGINE START POSITION WERE REQUIRED TO GET THE ENGINE TO START. UPON CLOSER INSP IT WAS DETERMINED THAT SELECTING THE ON OR START POSITION GENTLY WITHOUT SNAPPING THE LEVER INTO THE START POSITION COULD CAUSE THE MALFUNCTION. NO FAULT CODE WAS GENERATED. IT THOUGHT THAT DUE TO THE NR OF CONTACTS WITHIN THE SWITCH AND THE RATE OF FADEC INTERROGATION BEING 20 TIMES PER SECOND ANY CONTACTS WITH ARCING SURFACES MAY NOT BE PASSING CURRENT QUICKLY ENOUGH IF SELECTED SLOWLY TO THE START POSITION. REPLACED 8 SUCH SWITCHES IN 50,000 FLIGHT HOURS. MOST SWITCH PROBLEMS BUT NOT ALL HAVE GENERATED A FAULT CODE INDICATING A PROBLEM WITH THE SWITCH ON THE AC VEMD REQUIRING REPLACEMENT. ONLY TWICE DID THE SWITCH COMPLETELY FAIL. SUGGEST SNAPPING SWITCH INTO POSITION, WILL EXTEND LIFE. (K)