COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Bell Helicopter Textron Canada (BHTC) 407 Series Helicopters
AD/BELL 407/7 Tail Rotor Hanger Bearing Support Inspection 5/99
Applicability: Bell (BHTC) Model 407 helicopters serial numbers 53000, 53002 through 53065,
53067 and 53069 through 53075.
Requirement: Perform a shimming procedure on the tail rotor hanger bearing support and the bearing hanger on the tail boom in accordance with the procedures specified in BHTC Alert Service Bulletin (ASB) no. 407-97-7 dated 27 February 1997.
Note: Transport Canada Airworthiness Directive CF-97-08, dated 08 July 1997 refers.
Compliance: At the next scheduled inspection but no later than 01 August 1999. This Airworthiness Directive becomes effective on 20 May 1999.
Background: In service reports have shown that some aircraft have developed a gap between the tail rotor hanger bearing support and the bearing hanger on the tail boom. This situation, if not corrected could lead to serious vibration of the tail rotor drive shaft and, eventually, to total disintegration of the shaft. This Directive introduces a shimming procedure to eliminate the gap and the possibility of damaging vibration of the tail rotor drive shaft.
Overview
The Civil Aviation Regulations 1998, enacted by the Australian Parliament, govern various aspects of civil aviation within the country. One particular legislative instrument, F2006B04642, pertains to specific airworthiness directives aimed at enhancing aviation safety. This directive, which became effective on 20 May 1999, targets the Bell Helicopter Textron Canada (BHTC) 407 Series Helicopters, specifically those within certain serial number ranges. The problem it addresses is the development of a gap between the tail rotor hanger bearing support and the bearing hanger on the tail boom, which if left unaddressed, could lead to severe vibrations of the tail rotor drive shaft and potentially cause its complete disintegration. The policy objective of this directive is to mandate a shimming procedure to eliminate such gaps, thereby preventing any potential catastrophic failure and ensuring the continued airworthiness of affected helicopters.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105 under the Civil Aviation Safety Authority, encompasses a range of airworthiness directives designed to ensure the safety of aircraft operations within Australian airspace. One such directive, AD/BELL 407/7, applies exclusively to Bell (BHTC) Model 407 helicopters with serial numbers ranging from 53000, 53002 through 53065, 53067, and 53069 through 53075. This directive mandates that a shimming procedure on the tail rotor hanger bearing support and the bearing hanger on the tail boom must be performed in accordance with the procedures specified in BHTC Alert Service Bulletin (ASB) no. 407-97-7 dated 27 February 1997. This requirement stems from reports indicating a potential gap that could lead to serious vibration of the tail rotor drive shaft, potentially resulting in the disintegration of the shaft. Compliance with this directive is mandatory, with the inspection and required procedure to be conducted at the next scheduled inspection but no later than 1 August 1999, with the directive becoming effective from 20 May 1999. This regulation underscores the importance of maintaining stringent safety standards for specific aircraft models to prevent hazardous conditions during flight operations.
Key Provisions
The Civil Aviation Regulations 1998, under PART 39 - 105, contain specific Airworthiness Directives (AD) that are critical for maintaining the safety of aircraft. One such directive, AD/BELL 407/7 (section 5/99), pertains to Bell Helicopter Textron Canada (BHTC) 407 Series Helicopters. It mandates that certain serial numbered helicopters (53000, 53002 through 53065, 53067 and 53069 through 53075) must undergo a specific inspection and shimming procedure for the tail rotor hanger bearing support and the bearing hanger on the tail boom. This requirement is detailed in BHTC Alert Service Bulletin (ASB) no. 407-97-7 dated 27 February 1997, which was also referenced in Transport Canada Airworthiness Directive CF-97-08 dated 08 July 1997. The inspection must be completed at the next scheduled inspection, but no later than 01 August 1999, with the directive becoming effective on 20 May 1999.
The AD/BELL 407/7 directive imposes specific obligations on the operators of the affected helicopters. They are required to adhere to the specified shimming procedures to ensure that the gap between the tail rotor hanger bearing support and the bearing hanger on the tail boom is eliminated. Failure to comply with these procedures could result in serious mechanical issues, such as vibration of the tail rotor drive shaft, potentially leading to the disintegration of the shaft. This poses a significant risk to the safety and airworthiness of the aircraft.
Non-compliance with the AD/BELL 407/7 directive can have serious legal and safety consequences. The Civil Aviation Regulations 1998 outline that operating an aircraft in contravention of an Airworthiness Directive is an offence. If found in breach of this directive, operators may face penalties. While the specific penalties are not detailed in the AD itself, they could include fines, enforcement actions, and potential grounding of the aircraft until compliance is achieved. These measures are in place to ensure that the safety standards are upheld and that the risk of mechanical failure is minimised.