N74608
Registered owner: PALMER THOMAS R, OH (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
Maintenance disclosures
Service Difficulty Reports filed with the FAA for this airframe. Filing is largely voluntary — the number of reports is not a measure of reliability. To verify a report, search its control number at the FAA SDRS site.
4 reports on file, 1995-07-25 – 2004-03-01.
Part: MOUNT — CRACKED (ENGINE)
DURING ANNUAL INSP, A CRACK WAS NOTED IN THE LOWER HORIZONTAL CROSSPIECE OF THE ENGINE MOUNT. THE CRACK IS APPROX .5000 INCH AWAY FROM THE PILOT SIDE END OF THIS TUBE, NEAR THE WELD THAT ATTACHES THIS TUBE TO THE DIAGONAL TUBE THAT ATTACHES TO THE FIREWALL LOWER PILOT SIDE SUPPORT BRACKET. THIS SAME CRACK LOCATION HAS BEEN SEEN IN SEVERAL AIRCRAFT. APPEARS TO BE A POINT OF HIGH VIBRATION INDUCED STRESS, AS THERE IS LITTLE LOAD ON THE PART DURING OPERATION.
Part: BRUSH — WORN (ALTERNATOR)
ALTERNATOR FAILED TO CHARGE 672 HOURS AFTER OVERHAUL. INSPECTION REVEALED THAT ALTHOUGH BOTH BRUSHES HAD BEEN REPLACED DURING OVERHAUL, ONE BRUSH WAS FULLY WORN OUT WHERE THE OTHER WAS ONLY 50 PERCENT WORN. OVERHAULER SAID HE HAS SEEN THIS BEORE AND ATTRIBUTES IT TO POOR MANUFACTURING AND/OR QUALITY CONTROL BY THE BRUSH VENDOR. BOTH BRUSHES EXISTED IN THE SAME ENVIRONMENT AND RODE ON THE SAME ARMATURE AND THIS SHOULD HAVE WORN AT APPROXIMATELY THE SAME RATE.
Part: VALVE GUIDE — EXCESS WEAR (CYLINDERS 1-3)
NR 1 AND NR 3 CYLINDERS FAILED LYC SB 388B TEST FOR EXCESS WEAR (.035 INCH AND .043 INCH RESPECTIVELY). THESE EXACT SAME TWO GUIDES AND CORRESPONDING VALVES HAD BEEN PREVIOUSLY REPLACED AT 408 HOURS SINCE NEW ENGINE. FOUR-PROBE EGT/CHT SHOWED ALL TEMPS NORMAL AND BAFFLE SEALS WERE GOOD. GROUND RUN ENGINE AND COLLECTED OIL FROM ROCKER BOXES OF THE 4 CYLINDERS. FOUND NR 1 AND NR 3 CYLINDERS GETTING MUCH LESS THAN NR 2 AND NR 4. NR 2 AND NR 4 GUIDES PASSES SB 388B TESTS AND THEY HAVE 821 HOURS TTSN. IN THAT TIME, 2 SETS OF NR 1 AND NR 3 EXHAUST VALVES/GUIDES HAVE FAILED THE TEST IN SB 388B. SUBMITTER SUSPECTS POSSIBLE DESIGN PROBLEM THAT PROVIDES INSUFFICIENT OIL TO NR 1 AND NR 3 CYLINDERS.
Part: BEARING CAP — WORN (MAG ROTOR)
PART NR M-3485 HAS A STEEL BEARING PRESSED INTO AN ALUMINUM BEARING CAP. IT PROVIDES SUPPORT TO THE ROTOR. DURING ROUTINE 500-HOUR INSPECTION (500 TTSN), A BLACK POWDER-LIKE SUBSTANCE WAS SEEN THROUGHOUT THE MAG. FOUND STEEL BEARING WAS MOVING INSIDE THE BEARING CAP, ABRADING ALUMINUM PARTICLES AWAY TO CONTAMINATE THE MAG. SUSPECT EXCESSIVE CLEARANCE AT OPERATING TEMP. SUBMITTER RECOMMENDS: 1) TIGHTER PRESS FIT BETWEEN BEARING AND CAP, OR, 2) FLUSH SET SCREWS AROUND EXTERIOR SIDES OF CAP TO HOLD BEARING IN PLACE, OR, 3) MAKE ALUMINUM CAP OF STEEL TO AVOID DIFFERENT EXPANSION RATES.