AD Number: AD/PC-12/45
Subject: Windshield De-Ice System Wiring - Inspection/Replacement
Applicability: Model PC-12 and PC-12/45 airplanes, Manufacturer Serial Numbers (MSN) 322 through MSN 400 inclusive.
Requirement: 1. Perform an inspection for signs of heat damage of the wires, splices and related link wires in the area of terminal block (TB152) in accordance of paragraph 3 of Pilatus PC-12 Service Bulletin (SB) 30-009.
2. Perform a check of the wires and related link wires to verify that wires of correct size (American Wire Gauge [AWG]) are installed as specified in paragraph 3.B. of SB 30-0009 and Wiring Manual (WM) 30-40-00 and 30-40-10.
3. If any signs of heat damage or incorrect wiring are found during the Requirements 1 and 2 inspections, replace them in accordance with SB 30-009. Note: FOCA Switzerland AD HB-2005-079 refers.
Compliance: For Requirements 1 and 2 - Within the next 10 hours time-in-service but not later than three calendar months after the effective date of this Directive. For Requirement 3 - Before further flight. This Airworthiness Directive becomes effective on 18 February 2005. Background: The Swiss Federal Office for Civil Aviation (FOCA) has advised of a report of a Co-Pilot’s windshield de-ice system failure. The cause of the defect was found in an overheating of the return wire from the windshield heating system. Investigation revealed that the installation of the wiring in question was not in accordance with the specifications given in the applicable wiring diagrams (incorrect AWG). This could result in heat damage of the wiring and as a consequence, electrical arcing or possible fire in the overhead panel in the flight-compartment.

FMI: http://casa.gov.au/avreg/aircraft/ad/ADfiles/UNDER/PC-12/PC-12-045.pdf