AD/CESSNA 185/45 - Wing Lower Spar Cap Angle Stiffener

Overview

The Civil Aviation Regulations 1998, specifically within Part 39 - 105, were enacted to address safety issues within the aviation sector by the Australian Government. This legislation, administered by the Civil Aviation Safety Authority (CASA), aims to ensure that civil aviation operations are conducted safely and without undue risk to the public. The problem or gap addressed by this regulation is the safety concern arising from the modification of certain Cessna aircraft models, where the absence of a specific angle stiffener was found to compromise the structural integrity of the wings, potentially leading to in-flight failures. The policy objective of this particular airworthiness directive is to mandate the inspection and, if necessary, the reinforcement of the wing lower spar cap angle stiffener in specified Cessna models to prevent wing failure and ensure continued safe operation of the aircraft. This directive became effective on 5 November 1998, with compliance required within 50 hours of the directive's enactment for affected aircraft.

Scope and Application

The Civil Aviation Regulations 1998, as detailed in PART 39 - 105 of the Civil Aviation Safety Authority's Schedule of Airworthiness Directives, apply specifically to Cessna 185 Series aeroplanes, including models 185, 185A, 185B, 185C, 185D, 185E, A185E, and A185F, across all serial numbers, that have been modified with the wing extension supplemental type certificate (STC) SA00276NY or supplemental type approval (STA) SA93-136. This legislation is applicable on a national level under the Commonwealth of Australia, ensuring that the specified aircraft meet stringent safety standards. The directive mandates the inspection and, if necessary, installation of angle stiffeners to prevent potential wing failure, which could lead to loss of control. Compliance with these requirements is mandatory, with a deadline of 50 hours in service after 5 November 1998, unless the necessary actions have already been completed. The directive is effective from 5 November 1998, and its implementation ensures that the affected aircraft adhere to the safety standards set by the Civil Aviation Safety Authority.

Key Provisions

The main sections of the Civil Aviation Regulations 1998, PART 39 - 105, pertaining to the Cessna 185 Series Aeroplanes, specifically address the installation and inspection of an angle stiffener on the lower spar cap of the wings. Section 39-105.45 (AD/CESSNA 185/45) mandates that the inside of the left and right wings, aft of the spar and nearest where the strut connects to the wing, must be inspected between Wing Station (WS) 90 and WS 110. The inspection must be conducted in accordance with Part A of the Accomplishment Instructions of Air Research Technology Inc. (ART) Service Bulletin No. SB-1-96, Issue 1, dated 11 April 1996. If an angle stiffener is not found, a stainless steel reinforcement strap must be installed on the underside of each wing at WS 100.50, as per Part B of the same service bulletin. The directive applies to all Cessna 185 series models with wing extension supplemental type certificates (STC) SA00276NY or supplemental type approvals (STA) SA93-136 incorporated. These regulations impose several obligations on the aircraft owners and operators. Primarily, they must ensure that the specified inspection and, if necessary, installation of the angle stiffener or reinforcement strap are carried out within 50 hours of the aircraft being in service after 5 November 1998. The compliance deadline is strictly enforced, with the directive becoming effective on 5 November 1998. This means that any affected aircraft must be inspected and, if required, modified within the stipulated timeframe to remain airworthy. Failure to comply with these requirements can result in serious legal and safety consequences. The primary risk is the potential for wing failure during flight, which could lead to a loss of control of the aircraft. Such an event could result in severe accidents, injuries, or fatalities. Under the Civil Aviation Act 1988, non-compliance with airworthiness directives can lead to enforcement actions by the Civil Aviation Safety Authority (CASA). These actions can include fines, suspension or revocation of aircraft certificates, and potential criminal charges if negligence or willful misconduct is proven. The maximum penalties for non-compliance can vary, but they can include significant fines and imprisonment terms, reflecting the seriousness of ensuring air safety.