N4082T

Part: BRACE — CRACKED (LT MLG) · airframe 28,860 hrs

CRACKS IN AFT MAIN GEAR SIDE BRACE FITTING ASSEMBLY P/N 40294-00. WE INITIATED A DYE PENETRANT INSPECTION PROGRAM ON THE FORWARD AND AFT MAIN GEAR SIDE BRACE FITTING ASSEMBLIES OF OUR PIPER CHIEFTAIN NAVAJO FLEET. THE INITIAL INSPECTION OF OUR AIRCRAFT REVEALED THAT SEVERAL OF THE AFT FITTING ASSEMBLIES ON BOTH THE LEFT AND RIGHT LANDING GEAR HAVE CRACKS LOCATED IN THE LOWER INBOARD WEB OF THE SIDE BRACE (PIPER PART NUMBER 40294-00). AS A RESULT OF FINDING THESE CRACKS, WE HAVE ADDED A 1,000 HOUR SPECIAL INSPECTION TO OUR PA31-350 AAIP, SO THAT WE MAY MONITOR AND REPLACE ANY ASSEMBLIES WHICH EXHIBIT THE CRACKING FOUND IN THE FITTING ASSEMBLIES. IT IS INTERESTING TO NOTE THAT THE CRACKS HAVE ONLY BEEN FOUND IN THE AFT ASSEMBLIES ON OUR AIRCRAFT.

Part: TRUNNION — CRACKED (RT MLG) · airframe 28,630 hrs

DYE PENETRENT INSPECTION REVEALED SMALL CRACK BEGINNING TO FORM ON TRUNNION JUST BELOW THE BUSHING AREA ALONG A CASTING RIDGE. THIS WAS THE RIGHT AFT MLG TRUNNION. IDENTICAL PART IS USED ON BOTH AFT TRUNNION, LEFT SIDE NOT CRACKED. FWD TRUNNIONS (DIFFERENT PART NUMBER) NOT FOUND TO BE CRACKED AT THIS TIME. ALTHOUGH TOTAL PART TIME IS NOT KNOWN, IT IS ASSUMED THAT THESE ARE ORIGINAL EQUIPMENT, WE HAVE NEVER REPLACED THESE BEFORE ON ANY OF OUR FLEET OF 8 OTHER NAVAJO CHIEFTANS.

Part: UNKNOWN — UNKNOWN (UNKNOWN) · airframe 6,484 hrs · 544 cycles

ON 5/25/04, WHILE RETURNING, THE PILOT NOTICED AN INTERMITTENT LOSS IN MANIFOLD PRESSURE ON THE RT ENGINE. A GRADUAL LOSS OF OIL PRESSURE BEGAN TO DEVELOP SO THE PILOT SHUT DOWN THE ENGINE AS A PRECAUTIONARY MEASURE AND CONTINUED ON COURSE TO FAI. AIRPLANE LANDED WITHOUT PROBLEMS. MAINT THOROUGHLY INSPECTED THE ENGINE AND FOUND NO MAJOR DEFECTS. OIL WAS ADDED TO BRING THE LEVEL FROM FOUR TO ELEVEN QUARTS AND OPERATIONAL CHECK FLIGHT WAS CONDUCTED TO SEE IF THE PROBLEM PERSISTED. AFTER THE CHECK FLIGHT, THE OIL FILTER WAS REINSPECTED AND NO DEFECTS WERE NOTED. AIRCRAFT RETURNED TO SERVICE.

Part: WASTEGATE VALVE — LEAKING (TURBOCHARGER)

AIRCRAFT ENROUTE, MANIFOLD PRESSURE AND OIL PRESSURE STARTED DECENDING. AIRCRAFT LANDED. MECHANICS FOUND WASTEGATE LEAKING OIL FROM DRAIN. WASTEGATE REPLACED, TESTED ON RUNUP, WAS SATISFACTORY. AIRCRAFT RETURNED TO SERVICE.

Part: GASKET — MISINSTALLED (LT ENGINE)

FLIGHT DEPARTED, PILOT NOTICED FLAMES FLICKERING THROUGH THE INSPECTION DOOR ON THE LEFT ENGINE AFTER REDUCING POWER, HE NOTED NO OIL PRESSURE AND SECURED THE ENGINE. THE AIRCRAFT RETURNED TO AIRPORT WITHOUT FURTHER INCIDENT. IT WAS DISCOVERED THAT CONVERTER KIT LW-13904D HAD BEEN INSTALLED SEVERAL HUNDRED HOURS PRIOR WITHOUT THE TECHNICIANS KNOWLEDGE OF THE REQUIREMENTS OF MSB 543A SUPP NR1 ENGINE IS RETIRED FROM SERVICE.

Part: PUMP — INOPERATIVE (FUEL SYSTEM)

DURING POST INSPECTION GROUND RUN, IT WAS OBSERVED THAT THE RIGHT ENGINE WOULD NOT RUN WITH OUT BOOST PUMP ASSISTANCE. WHEN REMOVED IT WAS NOTED THAT THE SHAFT ROTATED WITH ROUGHNESS. PUMP WAS REPLACED.

Part: REGULATOR — LEAKING (HEATER)

DURING INSPECTION EVENT FUEL WAS OBSERVED COMING OUT OF THE DRAIN FOR THE COMBUSTION HEATER. THE FUEL PRESSURE REGULATOR WAS REMOVED AND FOUND TO LEAKING FROM PARTING SURFACE. PART WAS REPLACED PER SB. RECOMMEND MACHING THE HOUSING AND USING AN (ORING TYPE SEAL).

Part: CHANNEL — CRACKED (NLG)

DURING INSPECTION, THIS AREA WAS LOOKED AT AFTER FINDING OTHER AIRCRAFT WITH THIS CHANNEL CRACKED THE PART WAS REMOVED AND REPLACED. IT MAY BE THAT THE CUT OUT NOT BEING DRESSED TO RELIEVE THE STRESS CAUSED THE PART TO FAIL AS EXTRA STRESS IS INDUCED FROM THE NOSE GEAR ACTUATOR ATTACH BRACKETS , 2 REAR BOLTS COMING THROUGH THE CHANNEL. THE OUTBOARD ACTUATOR ATTACH HOLE WAS CRACKED FROM THE HOLE TO THE EDGE OF THE CHANNEL.

Part: REGULATOR — LEAKING (HEATER)

UPON INSPECTING THE FUEL PRESSURE REG IT WAS FOUND THAT THE REGULATOR WAS LEAKING PROBABLY FROM THE LOWER BODY PARTING SURFACES. REMOVED AND REPLACED UNIT LEAK CHECK GOOD.

Part: PUMP — FAILED (FUEL SYSTEM)

PILOT REPORTED DECREASE IN FUEL PRESSURE AT CRUISE POWER SETTINGS. PUMP WAS REMOVED AND REPLACED.

Part: CAMSHAFT — DAMAGED (ENGINE)

DURING INSPECTION, METAL CONTAMINATION WAS DISCOVERED IN OIL FILTER. A CHECK OF VALVELIFT WAS DONE AND IT WAS DISCOVERED THAT NR5 AND NR6 INTAKE LOBES WERE EXCESSIVE. NR6 CYLINDER WAS REMOVED AND DAMAGE OBSERVED ON THE CAM LOBES AND TAPPET FOLLOWERS. NOTE: THIS IS THE 14TH ENGINE IN 3 YEARS. LUBRICATION PRACTICES HAVE BEEN MONITORED/ POOR QUALITY CONTROL ON NITRIDING.

Part: PUMP — MALFUNCTIONED (LT ENGINE)

ON PRE INSPECTION RUN UP, IT WAS NOTICED THAT THE FUEL PRESSURE WAS LOW ON THE LEFT ENGINE. THE FUEL PRESSURE WAS ADJUSTED IN ACCORDANCE WITH INSTRUCTIONS IN THE SERVICE MANUAL FOR THE AIRCRAFT WHICH RESULTED IN NO CHANGE IN THE FUEL PRESSURE ON THE GROUND RUN CHECK. THE PUMP WAS RETIRED FROM SERVICE.

Part: BULKHEAD — CRACKED (FUSELAGE)

DURING INSPECTION, A CRACK WAS OBSERVED ON DOUBLER PN 40682-10 AT BS 317.75. THIS WAS LOCATED AT THE UPPER LEFT BOLT ALONG THE TOP OF THE WASHER. CRACK WAS THREE-FOURTHS OF AN INCH IN LENGTH. AFTER REMOVING THE VERTICAL, THE TOP OF THE BULKHEAD WAS FOUND TO HAVE A CRACK 1.25 INCHES ON THE LEFT SIDE SPANNING THE UPRIGHT BRACE. THIS AIRCRAFT DOES NOT HAVE AD 96-12-12 APPLY PER THE SERIAL NUMBER. SUBMITTER RECOMMENDED THIS AREA BE LOOKED AT ON THE NEXT HEAVY INSPECTION. AIRCRAFT TOTAL TIME IN SERVICE 14,601.7 HOURS. (X)

Part: REGULATOR — LEAKING (HEATER)

DURING ROUTINE INSPECTION, REGULATOR WAS FOUND LEAKING AT PARTING SURFACES. (X)

Part: SWITCH — FAILED (AFCS)

PILOT REPORTED AUTOPILOT WOULD DIS-ENGAGE IN FLIGHT AND WOULD NOT RE-ENGAGE. SYSTEM WAS CHECKED ON GROUND PER A/C P.O.H. ACCELEROMETER SWITCH WOULD NOT TEST IN THE UP POSITION AND WAS INTERMITTENT IN THE DOWN POSITION. SWITCH WAS REMOVED FROM SERVICE. (X)

Part: REGULATOR — LEAKING (HEATER FUEL)

DURING A NORMAL AIRCRAFT INSPECTION, FORWARD FUEL PRESSURE REGULATOR WAS FOUND TO BE EXTREMELY STAINED FROM FUEL LEAKING BETWEEN BODY HALVES. TIME IN SERVICE ON THIS PARTICULAR REGULATOR IS UNKNOWN. THERE HAS BEEN APPROX 120 HOURS SINCE LAST INSPECTED AND 1,191.2 HOURS TIME IN SERVICE ON THE HEATER ASSY ITSELF. SUBMITTER SUGGESTED THAT PARTICULAR ATTENTION BE PAID TO INSPECTING THESE REGULATORS DUE TO EXCESSIVE FAILURES IDENTICAL TO THIS ONE. (X)

Part: SWITCH — FAILED (AFCS)

AUTOPILOT: UNIT FAILED TEST FUNCTION IN THE UP POSITION. UNIT IS NEWER, MOD SEEMS TO FAIL WITHIN SAME TIME FRAME AS PREVIOUS MODEL. RECOMMEND ELIMINATING THIS SWITCH FROM SYSTEM AS PILOT CAN OVERRIDE AN EXTREME PITCH UP OR DOWN MANUALLY. (X)

Part: SWITCH — MALFUNCTIONED (AUTOPILOT)

AUTOPILOT WILL NOT TEST UP OR DOWN.

Part: SWITCH — MALFUNCTIONED (AUTOPILOT)

AUTOPILOT WILL NOT TEST DOWN, ALWAYS TESTS UP.

Part: SWITCH — MALFUNCTIONED (AUTOPILOT)

AUTOPILOT WILL NOT ENGAGE.

Part: SWITCH — MALFUNCTIONED (AUTOPILOT)

AUTOPILOT KICKS OFF IN SMOOTH AIR.

Part: SWITCH — MALFUNCTIONED (AUTOPILOT)

AUTOPILOT INTERMITTENLY KICKS OFF IN SMOOTH AIR. WILL NOT TEST UP OR DOWN. REMOVED UNIT AND BENCH TESTED; DUPLICATED MALFUNCTION.

Part: SWITCH — MALFUNCTIONED (AUTOPILOT)

AUTOPILOT WILL NOT TEST UP, ALWAYS TESTS DOWN.

Part: SWITCH — MALFUNCTIONED (AUTOPILOT)

AUTOPILOT KICKS OFF IN SMOOTH AIR.

Part: SWITCH — MALFUNCTIONED (AUTOPILOT)

SUCCESSFULLY TEST UP ONLY INTERMITTENTLY; AFTER SUCCESSFUL DOWN TEST, WILL NOT TEST UP UNTIL TEST SWITCH HAS REPEATEDLLY BEEN PLACED IN UP POSITION. WHEN AUTOPILOT ENGAGED AND ENGINES ARE BROUGHT UP TO HIGH RPM, THE FOLLOWING OCCURS. AP ANNUNCIATOR LAMP BRIGHTENESS DIMS SLIGHTLY. AP ANNUNCIATOR LAMP INTENSITY CONTINUOUSLY VARIES FROM BRIGHTNESS NOTED ABOVE TO HALF. ROLL AND PITCH SERVOS WILL NOT DRIVE. COMMAND BARS FUNCTION PROPERLY. UNIT REMOVED AND BENCH TESTED. MALFUNCTION DUPLICATED ON BENCH.

Part: SWITCH — MALFUNCTIONED (AUTOPILOT)

AUTOPILOT WILL NOT ENGAGE.

Part: SWITCH — INTERMITTENT (AUTOPILOT)

AUTOPILOT INTERMITTENTLY WILL SUCCESSFULLY TEST. AUTOPILOT INTERMITTENTLY WILL NOT ENGAGE.

Part: SWITCH — MALFUNCTIONED (AUTOPILOT)

AUTOPILOT WILL NOT ENGAGE.

Part: SWITCH — MALFUNCTIONED (AUTOPILOT)

DURING A PRE-FLIGHT CHECK, PILOT TESTED THE ACCELEROMETER SWITCH. IT WOULD TEST OK IN THE DOWN POSITION, BUT WOULD NOT TEST IN THE UP POSITION. SUBMITTER RECOMMENDS THAT THE PART BE TSO'D OUT OF THE SYSTEM.

Part: SWITCH — FAILED (AUTOPILOT)

PILOT REPORTED UPON COMPLETION OF PRE-FLIGHT CHECK, ACCELEROMETER SWITCH WOULD NOT TEST OR DISCONNECT AUTOPILOT AS REQUIRED BY POH INSTRUCTIONS. THE SYSTEM WAS FOUND TO DISCONNECT IN THE DOWN POSITION SOMETIMES, AND WOULD NOT DISCONNECT IN THE UP POSITION. THE SWITCH IS OF VERY POOR DESIGN AND CONSTRUCTION. INNER AND OUTER HOUSINGS ARE OF DISSIMILAR METAL AND DO NOT EXPAND AND CONTRACT AT THE SAME RATE NOT ALLOWING THE SWITCH TO MOVE AT DIFFERENT TEMPS. WHOLE SYSTEM IS OVER-ENGINEERED. ONE SIMPLE TSO TO REMOVE THE SWITCH FROM THE SYSTEM WOULD CURE THE PROBLEM. IF SWITCH IS USED FOR WHAT IT WAS DESIGNED, PILOT HAS ALREADY LOST CONTROL OF THE AIRCRAFT!!

Part: ACCELEROMETER — MALFUNCTION (AUTOPILOT)

AUTOPILOT WOULD KICK OFF IN STRAIGHT AND LEVEL FLIGHT WITH NO TURBULENCE. ALSO, THE ACCELEROMETER WOULD NOT TEST PROPERLY IN THE UP POSITION.

Part: FUEL PUMP — GASKET FAILED (ENGINE)

GASKET PUSHED OUT OF VALVE BODY AND DUMPED ALL THE FUEL OVERBOARD.