AD/B737/11 - Horizontal Stabilizer Centre Section - Rear Spar Upper Chord Attach Lugs

Overview

The Civil Aviation Regulations 1998, established by the Parliament of the Commonwealth of Australia, address the need for stringent safety standards in the aviation sector. Specifically, Part 39 - 105 of these regulations, which pertains to the Civil Aviation Safety Authority's schedule of airworthiness directives, was enacted to ensure the safety of aircraft operations. One such directive, AD/B737/11, was introduced to address a critical safety issue related to the Boeing 737 series aeroplanes. The directive mandates inspections of the horizontal stabilizer centre section's rear spar upper chord attach lugs, aiming to prevent potential structural failures that could lead to catastrophic outcomes such as the loss of the horizontal stabilizer. The policy objective is to enhance aviation safety by ensuring the integrity of key structural components of the aircraft, thereby protecting passengers, crew, and the general public from potential hazards.

Scope and Application

The Civil Aviation Regulations 1998, specifically within PART 39 - 105, mandate the application of Airworthiness Directives concerning Boeing 737 series aeroplanes, notably addressing the horizontal stabilizer centre section rear spar upper chord attach lugs. This directive applies to all 737-100, -200, and -200C models with specific line numbers, namely 316 to 322, and 325 onwards. The regulation necessitates an inspection protocol as detailed in the Flight Safety Inspection Program outlined in Boeing S.B. 737-55-1033. Compliance with this directive is essential to ensure the detection of any cracks in the lugs, which, if left unaddressed, could result in the loss of the horizontal stabilizer. The inspections must occur before the aeroplane exceeds 40,000 landings or 40,000 landings after a chord replacement or modification, whichever is later, and subsequently at intervals not exceeding 5,700 landings. The geographic and jurisdictional reach of this regulation is national, applying across all Commonwealth territories, and extends through subordinate instruments to maintain stringent safety standards within Australia's civil aviation framework.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, which pertains to the Civil Aviation Safety Authority's (CASA) schedule of airworthiness directives, includes an important directive for Boeing 737 Series Aeroplanes. The directive AD/B737/11 addresses horizontal stabilizer centre section rear spar upper chord attach lugs (section 10/86). This directive applies to all 737-100, -200, and -200C models with Line Numbers 316 to 322, and 325 and subsequent (section 10/86). The requirement set forth is that these aeroplanes must be inspected in accordance with the Flight Safety Inspection Program specified in Boeing S.B. 737-55-1033 (section 10/86). It is noteworthy that FAA AD 86-12-05 also references this directive. Compliance with this directive necessitates that inspections occur before the aeroplane exceeds 40,000 landings, or before it exceeds 40,000 landings following a chord replacement or modification in accordance with Option 1 of the Requirement Document, whichever is later (section 10/86). Subsequent inspections must be carried out at intervals not exceeding 5,700 landings (section 10/86). The obligations imposed by this directive are stringent and must be meticulously followed to ensure aviation safety. Operators of the specified Boeing 737 models must ensure that all inspections are conducted in alignment with the Flight Safety Inspection Program outlined in Boeing S.B. 737-55-1033. This entails detailed and regular checks of the horizontal stabilizer centre section rear spar upper chord attach lugs to detect any potential cracks. It is critical that these inspections are performed by qualified personnel and that any findings are appropriately documented and acted upon to prevent any risk to flight safety. Failure to comply with these inspection requirements could lead to significant safety issues, including the potential loss of the horizontal stabilizer. Any breach of the requirements outlined in AD/B737/11 could result in serious civil or criminal consequences. The Civil Aviation Regulations 1998 establish a framework under which non-compliance with airworthiness directives can lead to enforcement actions. If an operator fails to adhere to the inspection schedule or if inspections are not performed correctly, CASA may take enforcement actions against the operator. These actions could include fines, operational restrictions, or even the grounding of the affected aeroplanes. The severity of the penalties depends on the nature and extent of the non-compliance, but the overarching goal is to ensure that all safety directives are strictly observed to maintain the highest standards of aviation safety.