The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts.
Piper Meridian turboprops experienced another bout of teething pains with a new airworthiness directive requiring electronic control modules to be replaced with new ones.The airworthiness directive comes on the heels of reports of smoke in the cockpit and a loss of electrical system function. The electronic control modules can short circuit, with internal electrical arcing. In characteristic FAA understatement, the agency says the combination of smoke and loss of function could lead to the inability to properly control the airplane.Analysis of the control modules concludes there inadequate clearance and electrical isolation between the load terminal and the metal case. The load terminal can cut through the rubber insulating grommet and contact the metal case. The design flaw affects the pilots breaker panel, the co-pilots breaker panel, the dimmer lighting module, the stall vane heat module and the propeller heat module.The AD applies to about 152 airplanes. Piper will pick up the cost of the parts but most owners will pay an average of $780 in labor.
Missing Balance Weight
After a flight, the rudder balance weight was discovered to be missing from the top leading edge of the rudder. It was found lying on a taxiway.Further inspection revealed the airplane had not been damaged. The weight assembly was inspected and all screw inserts were serviceable. The weight was reinstalled and checked for security, and at that time the rudder assembly was found to be unbalanced. The technician concluded that the wrong hardware was used to install the assembly and over time it worked loose. No recent work had been done on the rudder or weight assembly. The airplane had over 8,000 hours.
During a routine inspection, the technician found the valve key retainers on the exhaust valve were worn where they contact the rotor cap.The wear was radial and about 0.020 to 0.030 inches deep. There was no strong indication of wear on the rotor cap nor a groove in the valve stem. The engine had 721 hours since overhaul.
Broken Door Hinge Pin
During an annual inspection, the lower right door hinge pin was found to be broken in three places. The condition is easy to spot by observing the pin as the door is opened. If the ends of the pin do not turn equally, then the pin is broken.
Cracked Prop Counterweight
During flight, the pilot noted a vibration that appeared to originate at one engine. The pilot reduced power and landed safely.Inspection revealed the propeller counterweight had shifted on the ferrule due to a fatigue crack in the forward bolt hole. The part had been in service about 700 hours.
Failed Turn Coordinator
The pilot reported the turn coordinator failed during IFR flight.The technician discovered the unit worked on the ground. The pilot then departed VFR and it continued to work.
During a runup, the pilot found the left magneto was inoperative. Inspection revealed the Slick Start magneto start boost box installed under an STC had malfunctioned and grounded the left magneto. The mechanic replaced the box and the problem was solved. The part had been in service 15 hours.
Broken Oil Cooler
During flight, the pilot noticed an oil pressure drop. He declared an emergency and landed safely.Inspection revealed the belly of the airplane was covered with oil. Further inspection revealed oil leaking from the right rear fins of the oil cooler.
Corroded Wing Spar
During an inspection associated with AD 2002-26-02, the technician removed both wings and fuel tanks.Four quarter-sized spots of light corrosion were found on the forward side of the front center section spar. The corrosion was cleaned and the entire area treated with corrosion preventive.