AIRWORTHINESS DIRECTIVE For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section. Beechcraft 1900 Series Aeroplanes AD/BEECH 1900/39 AC Inverters and Synchronisation Wire 4/2003 Applicability: Model 1900D aeroplanes in the following groups: Group 1 aeroplanes - serial numbers (S/N) UE-1 through UE-265, Group 2 aeroplanes - S/N UE-266 through UE-388, and Group 3 aeroplanes - S/N UE-389 through UE-410. Requirement: 1. For Group 1, 2 and 3 Aeroplanes - Inspect the AC inverter, in accordance with the Accomplishment Instructions section of Raytheon Aircraft Service Bulletin SB 24-3215, Rev. 1, June 2001, to determine if the KGS Electronics AC Inverter part number (P/N) SPC-10(PW), with a serial number in the range of 306 through 803, is installed and is identified as Mod 2DD. If, by checking the aeroplane logbook or by visual inspection, it can be positively shown that a Mod 2DD inverter is installed, then Requirement 2 is not applicable. 2. For Group 1, 2 and 3 Aeroplanes - If, during the Requirement 1 inspection, it is found that the Mod 2DD inverter is not installed, accomplish the AC inverter modification in accordance with the Accomplishment Instructions section of SB 24-3215, Rev. 1 and with the Model 1900D Airliner Maintenance Manual (AMM). 3. For Group 1 Aeroplanes - Inspect the AC inverter in accordance with the Accomplishment Instructions section of SB 24-3215, Rev. 1 to determine if United Stated Federal Aviation Administration (FAA) Supplemental Type Certificate STC SA00245WI-D is installed. If, by checking the logbook or visual inspection, it can be positively shown that FAA STC SA00245WI-D has never been installed, then Requirement 4 is not applicable. 4. For Group 1 Aeroplanes - If during the Requirement 3 inspection, FAA STC SA00245WI-D is found to be installed, accomplish the AC inverter Synchronisation (sync) wire shield modification in accordance with the Accomplishment Instructions section of SB 24-3215, Rev. 1 and with the Model 1900D AMM. Beechcraft 1900 Series Aeroplanes AD/BEECH 1900/39 (continued) 5. For Group 2 Aeroplanes - Accomplish the AC inverter sync wire shield modification in accordance with the Accomplishment Instructions section of SB 24-3215, Rev. 1 and with the Model 1900D AMM. 6. For Group 1, 2 and 3 Aeroplanes - Any KGS Electronics AC inverter P/N SPC-10(PW), with a S/N between 306 through 803 not identified as having Mod 2DD incorporated, may not be installed on any aeroplane as a replacement part. 7. For Group 1 Aeroplanes - FAA STC SA00245WI-D may not be incorporated on any aeroplane unless the Requirement 4 AC inverter modification is accomplished. Note: FAA AD2003-04-26 Amdt 39-13075 refers. Compliance: For Requirement 1 - Before 21 October 2003. For Requirement 2 - Before further flight after the Requirement 1 inspection. For Requirement 3 - Before 21 October 2003. For Requirement 4 - Before further flight after the Requirement 3 inspection. For Requirement 5 - Before 21 October 2003. For Requirements 6 and 7 - As of the effective date of this Directive. This Airworthiness Directive becomes effective on 17 April 2003. Background: The FAA has received nine reports of electrical noise causing the alternating current (AC) inverter to shutdown on certain aeroplanes. These aeroplanes were all equipped with KGS Electronics AC Inverter P/N SPC-10(PW), Mod 2, serial numbers 306 to 803. The shutdown of the inverter resulted in the loss of the electronic flight information system (EFIS), Radio Magnetic Indicator (RMI), and related AC- powered systems. Additionally, some aeroplanes experienced the loss of engine torque indication. Beechcraft 1900 Series Aeroplanes AD/BEECH 1900/39 (continued) This Directive requires an inspection of the AC inverter and, if necessary modification of affected aeroplane. Inspection of some aeroplanes is also required to determine if modification of AC inverter sync wire shield is required. These actions are intended to prevent electrical noise causing the AC inverter to shut down, which could result in failure of key aircraft electrical systems. Such failure could lead to loss of flight instruments during a critical phase of flight. James Coyne Delegate of the Civil Aviation Safety Authority 5 March 2003 The above AD is notified in the Commonwealth of Australia Gazette on 26 March 2003.