AD/B767/8 Amdt 3 - Intermediate Pressure Check Valves

Overview

The Civil Aviation Regulations 1998, under Part 39 – 105 of the Civil Aviation Safety Authority Schedule of Airworthiness Directives, includes Airworthiness Directive AD/B767/8 Amdt 3, issued in 2000. This legislative instrument addresses safety concerns related to the intermediate pressure check valves in Boeing 767 series aircraft, particularly those equipped with specific Hamilton Standard bleed pneumatic system check valves. The directive was introduced in response to reports of valve fragments becoming lodged in other pneumatic system components, resulting in engine damage and cracked valves. The policy objective is to ensure the ongoing airworthiness of these aircraft by mandating regular inspections and maintenance of the check valves to prevent such incidents. The Civil Aviation Safety Authority, as the relevant authority, issued this directive to ensure compliance with safety standards and to protect both the aircraft and its occupants.

Scope and Application

This airworthiness directive applies specifically to Boeing 767 series aircraft that are equipped with Hamilton Standard 8th stage bleed pneumatic system check valves, identified by the parts numbers 773856-3 through -15. The directive mandates that inspections of the affected check valves be conducted in accordance with Hamilton Standard Service Bulletin 36-2078, or its revisions 1 and 2. Compliance with Hamilton Standard Service Bulletin 36-2116, whether in its original issue or as Revision 1, serves as the terminating action for this directive. The directive outlines that inspections must be performed within 500 flight hours following the directive's effective date and subsequently at intervals not exceeding 1200 flight hours. This directive, issued by the Civil Aviation Safety Authority (CASA), supersedes previous amendments and aligns with FAA AD 90-12-02, which in turn supersedes AD 90-04-10. This directive is applicable across the Commonwealth of Australia and extends to all aircraft operators within its jurisdiction, ensuring that safety measures are uniformly enforced to mitigate risks associated with valve failures and associated damages.

Key Provisions

The Civil Aviation Regulations 1998, particularly in Part 39 - 105 under the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, specifically addresses the Boeing 767 series aeroplanes, with a focus on the intermediate pressure check valves. The Airworthiness Directive (AD) AD/B767/8 Amdt 3 issued under subregulation 39.1 (1) of CAR 1998, mandates that specific inspections and actions be taken on Boeing 767 aircraft equipped with Hamilton Standard 8th stage bleed pneumatic system check valves, Part Nos. 773856-3 through -15 (section 1). The directive requires the inspection of these check valves in line with Hamilton Standard Service Bulletin 36-2078, including its revisions, to address the identified unsafe conditions (section 2). Compliance with Hamilton Standard Service Bulletin 36-2116, either original or Revision 1, is considered the terminating action for this directive, ensuring that the identified issues are fully addressed (section 3). The obligations imposed by this AD are stringent and clear. Operators of Boeing 767 aircraft with the specified check valves must conduct the required inspections following the stipulated service bulletins. These inspections must be performed within 500 flight hours after the effective date of the AD and subsequently at intervals not exceeding 1200 flight hours (section 4). This requirement ensures that the identified risks are mitigated in a timely and consistent manner, safeguarding the aircraft's airworthiness. Failure to comply with the AD can result in significant consequences. The AD explicitly outlines that non-compliance with the mandated inspections and actions could lead to unsafe conditions persisting, potentially resulting in severe incidents such as fragments of failed valves lodging in other pneumatic system components, engine damage due to fragment ingestion, and cracked valve removals (section 5). Although specific penalties are not detailed within the AD itself, the broader regulatory framework under CAR 1998 allows for substantial penalties, including fines and imprisonment, for breaches of airworthiness directives. These penalties underscore the importance of strict adherence to the AD to ensure the safety and reliability of civil aviation operations.