Overview

The Civil Aviation Safety Authority (CASA) issued the Airworthiness Directive (AD) AD/SF340/96 in 2004 to address concerns about the reliability and safety of the starter generators in Saab SF340 Series aeroplanes, particularly the SF340A and SF340B models. This directive was introduced in response to reports from the Swedish Luftfartsverket (LFV) regarding premature failures of generator brushes, which could lead to engine start failures or low voltage situations during flight. The AD mandates repetitive inspections of the starter generator brushes to ensure continued airworthiness and safety, applying specifically to aircraft with certain serial numbers and requiring modifications to the generator control unit. The policy objective is to maintain high safety standards in aviation by preventing potential hazards associated with generator brush failures.

Scope and Application

This Airworthiness Directive (AD) issued by the Civil Aviation Safety Authority (CASA) applies specifically to Saab SF340A aeroplanes with serial numbers from SF340A-004 to -159 and Saab 340B aeroplanes with serial numbers from 340B-160 to -367, provided they do not have the Saab Aircraft Service Bulletin (SB) 340-24-026 (Mod 2533) incorporated. The directive mandates actions to address the unsafe condition identified in the generator brushes of these aircraft, which have been linked to premature failures that could result in engine start failures or low voltage situations during flight. The directive requires inspections of the starter generator brushes in accordance with Saab Aircraft SB 340-24-035, with specific timelines for compliance based on the time in service (TIS) of the generators at the effective date of the directive. The AD becomes effective on 30 September 2004, and its application is limited to the specified aircraft models and serial numbers. Compliance must be achieved within 600 to 800 hours TIS after each overhaul for generators with less than 800 hours TIS at the effective date, and within 100 hours TIS after the effective date for those with more than 800 hours TIS.

Key Provisions

This Airworthiness Directive (AD), issued under the Civil Aviation Safety Regulations 1998 (CASR), pertains specifically to Saab SF340A and Saab 340B aeroplanes with certain serial numbers that do not yet have Saab Aircraft Service Bulletin 340-24-026 (Mod 2533) incorporated. The AD, numbered AD/SF340/96, mandates that repetitive inspections of the starter generator brushes be carried out in accordance with Saab Aircraft SB 340-24-035. This directive applies to generators overhauled under MRB task 243104. It is important to note that generators overhauled under MRB Task 243103 or with brush replacement in accordance with MRB Task 243101 are exempt from this directive. The AD stipulates two different compliance timelines depending on the time in service (TIS) of the generators at the effective date of the directive. For generators with less than 800 hours TIS at the effective date, the inspections must be performed between 600 and 800 hours TIS after each overhaul. For generators with more than 800 hours TIS at the effective date, the inspection must be conducted within 100 hours TIS after the effective date and then between 600 and 800 hours TIS after each subsequent overhaul. This AD became effective on 30 September 2004. The primary obligation under this AD is for the aircraft operators to ensure that the specified repetitive inspections of the starter generator brushes are performed in accordance with the set timelines and instructions. Failure to comply with the AD may result in the aircraft being deemed unairworthy, which could lead to operational restrictions or grounding of the aircraft until compliance is achieved. The potential consequences of non-compliance include significant operational disruptions, financial penalties, and legal action by the Civil Aviation Safety Authority (CASA). The severity of the penalties can vary based on the extent of non-compliance and the impact on air safety.