AD/B767/72 - Static Inverter Replacement

Overview

The Civil Aviation Regulations 1998, as amended, introduce specific safety directives aimed at enhancing the operational safety of civil aircraft within Australian airspace. Part 39, specifically under AD/B767/72, addresses the critical issue of static inverter malfunctions in Boeing 767 series aeroplanes, as identified in Boeing Alert Service Bulletin 767-24A0085 dated 17 September 1992. This directive was enacted to mitigate the risk of electrical power loss to the standby bus during ground power transfer operations, which could lead to severe operational hazards such as the inability to restart engines in the event of a dual engine flameout. The policy objective, as articulated in the directive, is to ensure the safe operation of Boeing 767 series aircraft by enforcing timely inspections and necessary replacements of the static inverter, thereby safeguarding against potential flight safety incidents. Compliance with these directives is overseen by the Civil Aviation Safety Authority, ensuring adherence to stringent safety standards mandated by both Australian and international aviation authorities.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, addresses the safety directives for the Boeing 767 series aeroplanes through the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives. This particular directive, AD/B767/72, mandates that all model 767 series aircraft identified in Boeing Alert Service Bulletin 767-24A0085 dated 17 September 1992 must undergo a thorough inspection of their static inverter to determine the part number. If the part number S282T004-7 is identified on the static inverter, the aircraft must replace it with an improved model before further flight, accompanied by an operational test as outlined in the Boeing alert service bulletin. Additionally, static inverters bearing the part number S282T004-7 are prohibited from being used as replacements in Boeing 767 series aircraft, though existing installations of this part number may remain in service until the replacement requirement is fulfilled. The directive is applicable across the Commonwealth of Australia, and compliance dates are set for these requirements, with a specific focus on preventing the shutdown of the static inverter during power transfer, which could potentially result in engine restart difficulties during critical situations.

Key Provisions

The Civil Aviation Regulations 1998, specifically in Part 39 - 105, outline the Airworthiness Directives (ADs) which govern the maintenance and safety standards for aircraft operating within Australia. One such directive, AD/B767/72, pertains to the Boeing 767 series aeroplanes and mandates the replacement of a static inverter (section 1). The directive applies to all Boeing 767 series aircraft identified in Boeing Alert Service Bulletin 767-24A0085 dated 17 September 1992. The key requirement is to inspect the static inverter to determine its part number as per the aforementioned service bulletin. If the static inverter is identified as part number S282T004-7, it must be replaced with an improved model before further flight, and an operational test must be conducted in accordance with the service bulletin (section 1). Furthermore, static inverters with part number S282T004-7 must not be used as replacements in Boeing 767 series aircraft, although existing installations of this part number can remain in service until the directive is complied with. Compliance with these provisions is mandatory. Requirement 1 must be completed unless it has already been accomplished, and this must occur before 16 September 1994 (section Compliance, Requirement 1). Requirement 2, which prohibits the use of part number S282T004-7 static inverters as replacements, takes effect from 16 September 1993 (section Compliance, Requirement 2). Failure to adhere to these directives can result in serious safety implications, as highlighted by the Federal Aviation Administration (FAA) reports of the loss of 115 volt AC electrical power during ground power transfer operations, which have been confirmed through laboratory tests. Non-compliance could lead to the shutdown of the static inverter during power transfer, potentially resulting in an inability to restart the engines in the event of a dual engine flameout. The potential consequences for breaching these requirements are severe. The FAA AD 93-13-01 Amendment 39-8614 outlines the penalties and consequences for non-compliance with the directive. While the exact penalties are not specified in the legislative instrument, it is clear that non-compliance with Airworthiness Directives is taken seriously and can result in civil or criminal penalties, depending on the severity and intent of the breach. The FAA compliance time has been extended by approximately one month, indicating the importance of adhering to these safety standards to prevent any risk to flight operations.