Overview

The Civil Aviation Regulations 1998 (CAR 1998) were enacted to provide a comprehensive regulatory framework for civil aviation in Australia, aiming to ensure the safety and efficiency of air travel and operations within Australian airspace. One of the key mechanisms through which this is achieved is the issuance of Airworthiness Directives (ADs), which are regulatory mandates that require aircraft operators to address specific safety concerns. The AD/PC-12/25 issued by the Civil Aviation Safety Authority (CASA) under subregulation 39.1(1) of CAR 1998 is an example of such a directive. This particular AD addresses an issue with the Pilatus PC-12 Series aeroplanes where the operation of the windshield heater in the LIGHT mode during prolonged periods, especially in very cold outside air temperatures, could cause the circuit breakers to trip, rendering the windshield heating system ineffective and potentially leading to hazardous icing conditions. The directive mandates specific actions, such as modifying the aircraft's wiring and circuit breakers, updating the Pilots Operating Handbook with a restriction on using the LIGHT mode, and installing a placard to warn against this unsafe practice, to ensure the continued airworthiness and safety of the affected aircraft.

Scope and Application

This Airworthiness Directive (AD) issued under subregulation 39.1 (1) of the Civil Aviation Regulations 1998 (CAR 1998) pertains to all Pilatus PC-12 and PC-12/45 aeroplanes from Manufacturers Serial Numbers (MSN) 201 up to and including MSN 320, as well as those from MSN 101 up to and including MSN 200 where the old windshields have been replaced with new Pilatus Part Numbers 959.81.10.107 LH and 959.81.10.108 RH (PPG P/N NP172121-5 LH and NP172121-6 RH). The directive applies to these aircraft due to the risk of the windshield heater circuit tripping during prolonged operation in the LIGHT mode, which could lead to icing of the windscreen. The AD mandates specific actions to mitigate this risk, including the modification of the Pilots Operating Handbook (POH) and de-ice system, and the verification or installation of a placard on the DE-ICING panel. Compliance with the AD is required by specified deadlines, with modifications to the de-ice system to be completed within 200 hours of service or at the next inspection for maintenance release, whichever comes first. This directive is effective as of 16 October 2000 and supersedes the previous AD/PC-12/23, which had similar objectives but required different actions.

Key Provisions

The Airworthiness Directive (AD) issued under section 39.1(1) of the Civil Aviation Regulations 1998 (CAR 1998) specifically applies to Pilatus PC-12 Series Aeroplanes, namely Models PC-12 and PC-12/45 with certain Manufacturer Serial Numbers (MSNs) and windshield part numbers. This directive mandates corrective actions to address a safety concern regarding the operation of the windshield heater in the LIGHT position, which can cause the circuit breakers to trip, leading to a loss of windshield heating capability and potential icing of the windscreen. The directive requires operators to update the Pilots Operating Handbook (POH) by inserting Temporary Revision No 21, install a placard adjacent to the windshield heating switch if not already present, and modify the de-ice system wires and circuit breakers according to Pilatus Aircraft Ltd Service Bulletin 30-006 dated 22 May 2000. The obligations imposed by this AD include ensuring compliance with the specified timeline for each requirement. Specifically, operators must update the POH with Temporary Revision No 21 before 30 October 2000. They must also verify and install the placard on the DE-ICING panel before the same date. The modification of the windshield de-ice system must be completed within 200 hours of time in service after the AD's effective date or at the next inspection for a Maintenance Release, whichever comes first. Failure to comply with these obligations may compromise the airworthiness of the affected aircraft and expose operators to potential safety risks. Failure to adhere to the provisions of this AD can result in serious safety implications, as the corrective actions are designed to prevent the tripping of the circuit breakers during flight, which can lead to a loss of windshield heating and increased risk of icing. While the AD itself does not explicitly outline specific penalties for non-compliance, violations of the CAR 1998 can result in enforcement actions by the Civil Aviation Safety Authority (CASA). Such actions may include the issuance of a Notice of Proposed Civil Penalty, leading to fines or other civil consequences. In severe cases, CASA may take further enforcement action, including grounding of the aircraft, prosecution of individuals or companies, and potential criminal charges, especially if non-compliance results in an aviation accident or incident.