N238CH
Registered owner: BANK OF UTAH TRUSTEE, UT (owner ≠ operator)
Operators of this aircraft
Who operated this tail, and how firmly we know it.
No operator established for this aircraft.
Accident & incident history
No NTSB accidents or incidents on file for this aircraft.
Maintenance disclosures
SWASHPLATE ASSEMBLY REMOVED FOR SCHEDULED MAINTENANCE AND RETURNED TO RS FOR OVERHAUL ON SWO-047589-19. ROTATING RING FAILED SB 234-62-1048 INSPECTION REQUIREMENTS WITH AN EDDY CURRENT INDICATION GREATER THAN 25% FSH (ACTUAL 35% FSH). REFERENCE DISC-192262-19.
AFTER REMOVAL, DISASSEMBLY, AND CLEANING OF FIRST STAGE SUNGEAR OUT OF THE AFT TRANSMISSION THAT WAS REMOVED FOR HIGH SOAPS, VISUAL INSPECTION REVEALED A SIZABLE CHUNK MISSING FROM THE DRIVE SIDE OF A GEAR TOOTH. EVIDENCE OF MISSING MATERIAL HAS NOT BEEN THUS FAR FOUND ON CHIP PLUG OR IN REMAINING TRANSMISSION.
SUPPLEMENTARY INFORMATION; CHI ENGINEERING HAS INSPECTED THIS ARTICLE AND CONTACTED THE OIL MANUFACTURER (EASTMAN OIL) TO EVALUATE THE LUBRICATION PROPERTIES. NO SUSPECT CAUSES WERE IDENTIFIED. THE CONCLUSION BY ALL CONCERNED PARTIES WAS THAT THIS WAS AN ANOMALOUS EVENT
DURING FLUORESCENT PENETRANT INSPECTION OF SWASHPLATE ASSY, UPPER RETAINER FOUND TO HAVE 5 CRACKS. MECHANICAL TESTING, METALLURGICAL & CHEMICAL ANALYSIS PERFORMED ON A SUBJECT RETAINER & FOUND TO MEET HARDNESS & ELECTRICAL CONDUCTIVITY REQUIREMENTS. THE PART MEETS CHEMISTRY REQUIREMENTS & MICROSTRUCTURE WAS TYPICAL FOR THE HEAT TREATED CONDITION. RECURRING FAILURE WITH THE CRACKS ALWAYS LOCATED IN THE GROOVE WHICH IS AN OPTIONAL FEATURE FOR THIS PART.THE GROOVE CORNER RADII ACT AS STRESS RISERS, OPERATIONAL LOADS PLUS LOADS INDUCED DURING ASSEMBLY MAY INDUCE CRACKING. ENGINEERING DRAWING CALLS OUT FOR THE GROOVE IS OPTIONAL. MANUFACTURER WILL SPECIFY THE GROOVE NOT BE MACHINED IN THE PART.
ROTOR HEAD WAS REMOVED DUE TO A FWD GREEN BLADE LEADING EDGE HORIZONTAL PIN SEAL PROTRUDING. DURING DISASSEMBLY ON SWO-021196-16, THE MECHANIC FOUND THAT THE SEAL WAS INSTALLED IN A SLEEVE WHICH WAS COMING OUT OF THE SEAL BORE. THE SEAL/LINER WORE INTO THE GREEN PITCH SHAFT LEADING EDGE, NEAR THE FIXED DROOP STOP, ABOUT 0.006" AT THE DEEPEST FOR ABOUT 3 LINEAR INCHES. THE SLEEVE WAS A REPAIR SLEEVE INSTALLED AT THE MANUFACTURER OF THE HUB AND DOCUMENTED IN 09-RDE-0739. THIS CENTER HUB HAS BEEN SCRAPPED AND IT HAS BEEN DETERMINED THAT THIS REPAIR HAS NOT BEEN PERFORMED ON ANY OTHER HUBS. THE PITCH SHAFT HAS BEEN REMOVED FOR FUTURE REPAIR.
TWO CRACKS IN OUTBOARD ADAPTER END. CRACKS GO THROUGH AN OUTBOARD RIVET HOLE AND EXTEND AT A 45 DEGREE ANGLE INBOARD AND OUTBOARD TO THE ADAPTER EDGE. P/N 114D3204-3 ADAPTER END. (X)