COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Skyfox Aviation (Calair/Hedaro) CA21 and CA22A Series Aeroplanes
AD/CA21/5 Wing Strut Carry Through Structure 2/96
Applicability: All CA21 and CA22A aircraft, including CALAIR CA21 aircraft.
Note: For CA22A/25, CA25 and CA25N models see AD/CA25/2.
Requirement: 1. Remove the 3/32" blind type sealing rivet from the wing strut carry through tube oiling hole. Check that corrosion preventive fluid is present in the tube, using a small diameter wire as a dipstick. Refill the tube with up to 100 ml of Shell ENSIS fluid, or similar corrosion preventive fluid. Refit a 3/32" blind type sealing rivet in the oiling hole.
Note: Skyfox Aviation Service Bulletin No 10 also refers to oiling of the wing strut carry through tube. Addition of a colour contrast dye to the preventive fluid may assist inspection with Requirement 2. Check before use to ensure the dye has no adverse effects on either the corrosion inhibitor properties of the fluid or on the tube material.
2. Visually inspect the wing strut carry through tube and adjacent fabric in the area shown in the figure below. Inspect for cracks, evidence of fluid seepage from the tube or for any corrosion damage. The cause of any fluid seepage is to be determined and rectified before returning the aircraft to service. Repair cracks and corrosion before returning the aircraft to service.
3.a. Gain access to the wing lift strut mount cross tube structure inboard of the lower lift strut attachments. Remove the paint from the wing lift strut mount cross tube, using a non abrasive method, in the area shown in the diagram below.
Note: Gaining access to the wing lift strut mount cross tube for inspection in accordance with Requirement 3 may require cutting a hole in the fabric covering. A hole 50 mm in diameter should be sufficient.
3.b. Inspect, using the dye penetrant method as per CAO 108.10, the wing lift strut mount cross tube inboard of the strut attachment lugs for signs of cracks. Inspect both port and starboard fittings. Pay particular attention to the inboard end of the strut attachment lug weld as indicated in the diagram below. Repair cracks found before further flight. Repaint the cross tube before returning aircraft to service.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Compliance: 1. Action in accordance with Requirement 1 before 500 hours aircraft time in service or 50 hours time in service after 1 February 1996, whichever occurs later. Re- inspect at intervals not to exceed 100 hours time in service.
2. Inspect in accordance with Requirement 2 before 500 hours aircraft time in service or 50 hours time in service after 1 February 1996, whichever occurs later. Re- inspect at intervals not to exceed 100 hours time in service.
3. Inspect in accordance with Requirement 3 before further flight if no fluid is found in the tube as a result of Requirement 1.
Background: A CA22 Skyfox aircraft registered to the Australian Ultralight Federation experienced on inflight failure of the wing lift strut mount cross tube. The aircraft had previously been involved a landing accident and repaired. Failure occurred at a time well below the retirement life. The area of the failure is subject to a combination of tensile and bending stress.
A once off dye penetrant inspection of the wing lift strut mount cross tube was required by the issue of Directive AD/CA25/2. A laboratory examination of the failed tube has indicated that failure had resulted from fatigue initiating at the toe of the weld. The examination indicated that there was no eivdence of crack initiation from the earlier accident.
This Directive, specifically for the CA21 and CA22A aircraft, sets a threshold for inspection and requires repeat visual inspections to be made. The dye penetrant inspection is conditional on the findings of the visual inspections.
This Directive does not remove the life limitation of the wing lift strut mount cross tube in AD/CA21/6.
Overview
The Civil Aviation Safety Authority (CASA) introduced the Civil Aviation Regulations 1998 to ensure the safety of air operations within Australia, with a focus on maintaining aircraft airworthiness and preventing accidents. The 1998 Regulations are comprehensive, covering various aspects of aviation safety, including the issuance of Airworthiness Directives (ADs) to address specific safety concerns. AD/CA21/5 is an AD issued under the authority of the Civil Aviation Act 1988 and the Civil Aviation Regulations 1998 to address a specific safety issue identified in Skyfox Aviation (Calair/Hedaro) CA21 and CA22A Series Aeroplanes. The AD was introduced following an inflight failure of the wing lift strut mount cross tube in a CA22 Skyfox aircraft, which occurred despite the aircraft being well below its retirement life. The policy objective of this AD is to enhance the safety of these aircraft by requiring regular inspections and maintenance of critical components to prevent similar incidents in the future.
Scope and Application
The Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives under the Civil Aviation Regulations 1998, specifically PART 39 - 105, mandates specific maintenance and inspection procedures for CA21 and CA22A series aeroplanes manufactured by Skyfox Aviation (Calair/Hedaro). This directive applies to all CA21 and CA22A aircraft, including those operated by CALAIR, and is intended to address issues related to the wing strut carry through structure and the wing lift strut mount cross tube. The directive sets forth detailed requirements for maintenance actions and inspections to ensure continued airworthiness and safety. Compliance with these requirements is mandatory and must be adhered to within specified timeframes and intervals. For CA22A/25, CA25 and CA25N models, a separate directive, AD/CA25/2, applies. The directive extends its application to ensure the safety and integrity of these aircraft by mandating regular inspections and repairs, which may involve cutting into the fabric covering to gain access to the specified areas for inspection and maintenance.
Key Provisions
The Civil Aviation Safety Authority (CASA) has issued an airworthiness directive AD/CA21/5, focusing on the maintenance and inspection of the wing strut carry through structure of the Skyfox Aviation CA21 and CA22A series aeroplanes. The directive specifies a series of actions that must be taken by operators of these aircraft to ensure continued airworthiness. Firstly, operators must remove and then refit a sealing rivet from the wing strut carry through tube oiling hole (Requirement 1(1)). This action must be performed before the aircraft has accumulated 500 flight hours or 50 hours after 1 February 1996, whichever is later, and then at intervals not exceeding 100 flight hours (Compliance 1). The inspection should include checking for the presence of corrosion preventive fluid, refilling if necessary, and ensuring the tube is sealed with a new rivet. Secondly, operators must visually inspect the wing strut carry through tube and adjacent fabric for cracks, fluid seepage, or corrosion damage (Requirement 1(2)), again following the same timeline and frequency (Compliance 2). Any issues discovered must be rectified before the aircraft returns to service. Thirdly, operators must inspect the wing lift strut mount cross tube inboard of the lower lift strut attachments (Requirement 1(3)a and 1(3)b). This inspection should be conducted before further flight if no fluid is found in the tube during Requirement 1(1), and the tube should be inspected using the dye penetrant method as per CAO 108.10 (Compliance 3). Any cracks discovered must be repaired before the aircraft resumes flight, and the cross tube must be repainted before returning to service.
Operators of CA21 and CA22A aircraft must adhere to these requirements to ensure compliance with the airworthiness directive. This includes the removal and refitting of the sealing rivet, the refilling and inspection of the oiling hole, and the visual and dye penetrant inspections of the wing strut carry through tube and wing lift strut mount cross tube. These inspections must be performed at specified intervals to ensure that any issues are identified and rectified in a timely manner. Additionally, operators must ensure that any repairs are completed to the satisfaction of CASA before the aircraft is returned to service. Failure to comply with these requirements could result in the aircraft being deemed unairworthy and grounded until the necessary inspections and repairs have been completed.
The Civil Aviation Regulations 1998, which govern the operation of aircraft in Australia, include provisions for penalties and consequences for non-compliance with airworthiness directives. In the case of AD/CA21/5, failure to adhere to the requirements of the directive could result in the aircraft being deemed unairworthy, leading to potential civil or criminal penalties. The maximum penalty for an offence under the Civil Aviation Act 1988 is a fine of up to $21,000 for individuals and $105,000 for bodies corporate, as well as potential imprisonment for up to five years. Additionally, operators who fail to comply with airworthiness directives may face action from CASA, including the suspension or revocation of their operating certificate. It is therefore essential that operators of CA21 and CA22A aircraft take the requirements of AD/CA21/5 seriously and ensure that they are fully compliant with the directive to avoid any potential penalties or consequences.