Overview

The Civil Aviation Safety Authority (CASA) issued Airworthiness Directive AD/B737/203 in 2003, targeting specific models of Boeing 737 series aeroplanes. This directive was introduced to address safety concerns associated with the fuel system in certain Boeing 737 aeroplanes. The directive mandates the replacement of existing fuelling float switch and conduit assemblies in the main and centre fuel tanks with new, improved assemblies to prevent fluid contamination or wiring chafing, which could lead to fire or explosion. The directive was issued under subregulation 39.1(1) of the Civil Aviation Regulations 1998 and became effective on 20 February 2003. The objective was to ensure the airworthiness of the specified Boeing 737 aeroplanes by mitigating identified safety risks.

Scope and Application

The Airworthiness Directive issued under the Civil Aviation Regulations 1998, specifically targeting the Boeing 737 Series Aeroplanes, mandates the replacement of the existing fuelling float switch and conduit assemblies in the main and centre fuel tanks with improved versions. This directive applies to Model 737-600, -700, -700C, -800, and -900 series aeroplanes listed in Boeing Alert Service Bulletin 737-28A1142, Revision 2. The directive's aim is to rectify unsafe conditions by mitigating the risks of fluid contamination or wiring chafing, which could lead to a fire or explosion in the fuel tank. Compliance timelines vary based on the total hours in service of the aeroplanes, with stricter deadlines for those with higher accumulated flight hours. This directive is applicable nationwide within the Commonwealth of Australia and becomes effective as of 20 February 2003.

Key Provisions

The Airworthiness Directive (AD) AD/B737/203 mandates the replacement of the existing fuelling float switch and conduit assemblies in the main and centre fuel tanks of Boeing 737-600, -700, -700C, -800, and -900 series aeroplanes with new, improved assemblies (section 1). This action is necessary to correct an unsafe condition that could potentially lead to fluid contamination within the fuelling float switch or chafing of the wiring to the in-tank conduit, which may cause an ignition source, resulting in a fire and explosion in the fuel tank (section 1). This directive applies to aeroplanes listed in Boeing Alert Service Bulletin (ASB) 737-28A1142, Revision 2, dated 26 November 2002 (section 2). The replacements must be carried out in accordance with Work Packages I and II of the Accomplishment Instructions of Boeing ASB 737-28A1142, Revision 2 (section 3). Aeroplanes that underwent replacements before the effective date of this directive in accordance with Boeing ASB 737-28A1142, dated 7 February 2002, are deemed to be in compliance with this directive (section 3, Note 1). It is recommended that Work Package II be completed before Work Package I due to the lack of sleeving on the existing electrical wire installations of the centre fuel tank (section 3, Note 2). The AD imposes several obligations on the parties and entities it governs. Firstly, the directive mandates that the replacement of the existing fuelling float switch and conduit assemblies in the main and centre fuel tanks with new, improved assemblies be carried out in accordance with the instructions set out in the requirement section (section 3). Secondly, aeroplanes that have accumulated fewer than 5,000 total hours time in service (TIS) as of the effective date of this directive must comply within 2 years after the effective date of the directive (section 4). Aeroplanes that have accumulated 5,000 total hours TIS or more, but fewer than 10,000 total hours TIS as of the effective date of this directive must comply within 1 year after the effective date of the directive (section 4). Lastly, aeroplanes that have accumulated 10,000 total hours TIS or more as of the effective date of this directive must comply within 180 days after the effective date of the directive (section 4). Failure to comply with the AD may result in civil or criminal consequences. The AD does not explicitly state any specific offences, penalties, or consequences for breach. However, non-compliance with ADs issued by the Civil Aviation Safety Authority (CASA) can potentially result in the grounding of the aircraft, which may have severe financial and operational consequences for the operator. Additionally, CASA may take enforcement action against the operator for non-compliance, which may include fines, suspension or revocation of the operator's certificate, or other civil or criminal penalties as appropriate. It is essential for the parties and entities governed by this AD to adhere to the specified requirements to ensure the continued airworthiness and safety of the Boeing 737 series aeroplanes.