The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts.
Nose Gear Extension Failure
The aircraft sustained nose damage due to the nose gears failure to extend for landing. The propeller linkage runs down the outside of the nose landing gear tunnel, and is attached in two places with Adel clamps, stand-offs and AN-3 bolts. The aft attach hole is directly in line with the nose door actuator arm, p/n 2213022-14. This aircraft had the aft AN-3 bolt installed with the threads and nut protruding into the wheelwell. The hollow actuator arm impacted the protruding bolt, loosening it with each gear cycle and, eventually, locking it into a retracted position. This prevented gear extension. During repairs, the l/h tunnel side was replaced with a factory part (p/n 2213001-3) which came pre-drilled in the same location. Neither the maintenance manual nor the parts catalog reference prop cable routing.Part Total Time: Unknown.
Gear Retraction Failure
The landing gear failed to fully retract after takeoff. The mechanic found the wire soldered to the hydraulic power pack pressure switch (p/n 9880710-1) had corroded beneath the heat-shrink tubing near the solder joint and surmises acid core solder may have been used to attach the leads to the switch.Part Total Time: 195.0 hours.
Failing Slick Magneto
A 500-hour magneto inspection revealed internal arcing between a coil and a carbon brush, though the aircraft ran well with a 100-rpm drop (preflight check). Arc damage occurred to both a brush and spring, and the mechanic noted part of the distributor block was missing. He recommends mandatory internal magneto inspections during annual inspections.Part Total Time: 602.0 hours.
Main Bearing Delamination
One technician documented apparent delamination for an engines number three main bearing (p/n 634503), stating, All the brass or bronze separated from the bearing shell. The crankshaft number three journal does not show signs of oil starvation. Another submission describes p/n 630571 (bearing for prop-driven gear in engine crankcase) marked on packaging as p/n 630571. Bearing itself marked as p/n 634503; p/n 634503 is crankshaft main bearing. Purchased new from Teledyne Continental Motors. Bearings will fit in crankcase saddles when switched, but oil holes do not line up and bearing oil grooves are different widths. Could cause bearing failure/oil starvation.Part Total Time: Unknown.
Piper PA 31T3
An investigation produced noise and vibration from the blower when the Janitrol combustion heater was operated (p/n 89D22-2). The inspection found the heater motors frame and end-plates loose, the fan hub loose, and paper measuring 1.5 by 0.5 inches lodged in the fan louvers. The mechanic states, Paper caused the fan to be out-of-balance, which led to the fan and motor components vibrating loose and causing the motor (p/n CD-21402) to run hot.Part Total Time: unknown.