AD/CHA/22 Amdt 2 - Front Spar Wing Strut Upper Attachment Fitting

Overview

The Civil Aviation Regulations 1998, specifically Part 39 - 105, addresses safety concerns related to the maintenance and operation of aircraft. Enacted by the Parliament of Australia, these regulations aim to ensure the highest standards of safety and airworthiness across the aviation sector. One such regulation, AD/CHA/22 Amendment 2, pertains to the American Champion (Aeronca, Bellanca) Series Aeroplanes, focusing on the front spar wing strut upper attachment fittings. This amendment responds to reported incidents of fatigue cracking and failures in the fittings, particularly in the P/N 2-1976 and P/N 3-1658 models. The policy objective is to mitigate the risk of in-flight failures by mandating specific inspection and replacement procedures for these critical components, thereby enhancing the overall safety of these aircraft models in service.

Scope and Application

The Civil Aviation Safety Authority (CASA) Regulations 1998, specifically Part 39 - 105, addresses the airworthiness of American Champion (Aeronca, Bellanca) Series aeroplanes, particularly focusing on the 8KCAB model. The regulations mandate that for the P/N 2-1976 fittings, a magnetic particle inspection must be conducted in accordance with the procedures outlined in Civil Aviation Order 108-8 Issue 1, with a particular emphasis on the welds that connect the strut attachment bolt hole reinforcement plates to the forward and aft “U” channels. This requirement must be fulfilled either before the component time in service accumulates to 500 hours or within 50 hours of 3 September 1990, whichever is later, and subsequently at intervals not exceeding 250 hours of component time in service. Additionally, P/N 3-1658 fittings must be retired from service before exceeding 1500 hours of component time in service. These directives aim to mitigate the risk of fatigue cracking, as evidenced by five reported overseas occurrences, including one in-flight failure in P/N 2-1976 fittings on 8KCAB aircraft.

Key Provisions

The Civil Aviation Regulations 1998, specifically under Part 39 - 105, include an airworthiness directive (AD) that pertains to American Champion (Aeronca, Bellanca) Series Aeroplanes. This AD, known as AD/CHA/22 Amendment 2, focuses on the front spar wing strut upper attachment fittings on all model 8KCAB aircraft (1). The directive may be expanded to include other models, such as the aerobatic 7 series, based on future service experiences or analyses (1). For Part Number (P/N) 2-1976 fittings, the requirement is to remove the left and right front spar wing strut upper attachment fittings from the aircraft and perform a magnetic particle inspection following the procedures outlined in Civil Aviation Order (CAO) 108-8 Issue 1 (1). This inspection should particularly focus on the welds that connect the strut attachment bolt hole reinforcement plates to the forward and aft “U” channels. It is imperative that the fitting is re-protected after the inspection is completed (1). For P/N 3-1658 fittings, the requirement is to retire these fittings from service before they exceed 1500 hours of component time in service (1). Compliance with these requirements is strictly enforced. For P/N 2-1976 fittings, the inspection must be conducted before the component accumulates 500 hours of service time or within 50 hours of service time after 3 September 1990, whichever comes later. This initial inspection must be followed by subsequent inspections at intervals not exceeding 250 hours of service time (1). Notably, aircraft with fittings that have exceeded 500 hours of service time should not perform aerobatic manoeuvres until the initial inspection is completed (1). For P/N 3-1658 fittings, they must be retired from service before reaching 1500 hours of service time (1). Failure to comply with the airworthiness directive may result in serious safety risks. The directive stems from five reported overseas occurrences of fatigue cracking originating from the weld area, including one in-flight failure in P/N 2-1976 fittings on 8KCAB aircraft (1). The Federal Aviation Administration (FAA) AD 90-15-15 and American Champion Aircraft Corporation Service Letter 402 are referenced as foundational documents for these requirements (1). Any breach of these regulations could potentially lead to severe civil or criminal consequences, as the AD is designed to ensure the safety and airworthiness of the aircraft in question.