COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Bell UH-1 Series Helicopters
AD/UH-1/1 Tail Rotor Blades 9/96 DM
Applicability: All models fitted with tail rotor blades P/N 204-011-702-015 or -121 with serial numbers A-20262 to A-20268, A-20270 to A-20282, A-20284 to A-20287, A-20289 to A-20422, A-20424 to A-20428, A-20430 to A-20433, A-20435 to A-20464, A- 20466 to A-20497, A-20499 to A21019, A-21027 to A-21031, A-21041, A-21047, A-
21049, and A-21059
Requirement: 1. Clean the tail rotor (TR) blades using a mild detergent and water to remove soot and grime; and then visually inspect each TR blade for peeling, flaking, or bubbling paint, or visible corrosion along the bond lines, viewed from the root and tip ends of each blade, and at the abrasion strip bond line on both faces of the blade from the root to the tip.
2. If peeling, flaking, or bubbling paint is found remove the paint from the area and inspect for corrosion. If no corrosion is found refinish blade and return to service.
3. Remove from service any blade where corrosion is found. Replacement with blades not listed in the Applicability terminates this Directive.
Note 1: FAA AD 96-12-26 refers.
Note 2: BHTI ASB 204-96-48 Rev A refers.
Compliance: Within 10 hours time in service after 26 June 1996, thereafter at intervals not exceeding seven days.
Background: The manufacturer has reported that certain serial number tail rotor blades were manufactured with internal leading edge doublers fabricated from clad aluminium material instead of bare aluminium material. The bond strength of clad aluminium material declines rapidly with exposure to normal environmental conditions.
The condition, if not corrected could lead to debonding of the main spar leading edge doubler which in turn could cause failure of the TR blade and subsequent loss of control of the helicopter.
Overview
The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA), were enacted to ensure the safety of civil aviation within Australia. A specific directive within these regulations, AD/UH-1/1, was introduced in response to a safety concern identified with certain Bell UH-1 series helicopter tail rotor blades. The problem addressed by this directive involves the use of clad aluminium material for internal leading edge doublers in specific serial numbers of tail rotor blades, which has a reduced bond strength and can degrade rapidly under normal environmental conditions. If unaddressed, this degradation could lead to debonding of the leading edge doubler, resulting in the failure of the tail rotor blade and a subsequent loss of helicopter control. The directive mandates cleaning and inspection of the specified tail rotor blades to detect and rectify any signs of corrosion or paint degradation, ensuring the continued airworthiness of the helicopters and maintaining the high safety standards expected in civil aviation.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105 under the Civil Aviation Safety Authority Schedule of Airworthiness Directives, applies to all Bell UH-1 Series helicopters equipped with tail rotor blades part numbers 204-011-702-015 or -121, within specified serial number ranges. This directive is applicable across the Commonwealth of Australia, governing the maintenance and inspection of these particular helicopter components to ensure airworthiness and safety. The regulation mandates that tail rotor blades must be cleaned and visually inspected for peeling, flaking, or bubbling paint and visible corrosion. If such conditions are detected, the affected paint must be removed, and the area inspected for corrosion; if no corrosion is found, the blade can be refinished and returned to service, but if corrosion is present, the blade must be removed from service, and replacement with blades outside the specified serial numbers will terminate compliance with this directive. Compliance with these requirements must be achieved within 10 hours of time in service after the directive's issuance on 26 June 1996, and subsequently at intervals not exceeding seven days. The regulation extends its application through references to FAA AD 96-12-26 and BHTI ASB 204-96-48 Rev A, ensuring consistency with international standards and practices.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, addresses airworthiness directives through the Civil Aviation Safety Authority (CASA) Schedule. One such directive is AD/UH-1/1, which pertains to Bell UH-1 Series Helicopters with specific tail rotor blade serial numbers. This directive requires the cleaning of the tail rotor blades using mild detergent and water, followed by a visual inspection for peeling, flaking, or bubbling paint, and any visible corrosion along bond lines (section 1). If peeling or flaking paint is detected, it must be removed, and the area inspected for corrosion. If no corrosion is present, the blade can be refinished and returned to service. However, if corrosion is found, the blade must be removed from service (section 2). It is critical to note that replacement with blades not listed in the applicability section terminates this directive (section 3). The directive references FAA AD 96-12-26 and BHTI ASB 204-96-48 Rev A for further guidance.
Operators of Bell UH-1 Series Helicopters must adhere to the specified maintenance and inspection requirements outlined in the directive. This involves cleaning and inspecting the tail rotor blades within 10 hours of service after 26 June 1996, and subsequently at intervals not exceeding seven days (section Compliance). The directive mandates that any identified issues with the blades, such as peeling, flaking, or bubbling paint or visible corrosion, be addressed promptly. Non-compliance with these inspection and maintenance procedures could result in the unsafe operation of the helicopter, potentially leading to severe consequences including loss of control.
Failure to comply with the requirements of AD/UH-1/1 may result in significant legal and safety consequences. Operators found to be in breach of the directive may face civil penalties, including fines. Furthermore, continued operation of a helicopter with unaddressed issues could lead to criminal charges, given the potential safety risks. The exact penalties for breaches are not specified in the directive, but they may include both financial penalties and potential imprisonment depending on the severity of the non-compliance and its impact on aviation safety. It is imperative for operators to strictly adhere to the directive to avoid such repercussions and ensure the continued airworthiness of their aircraft.