COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Boeing 737 Series Aeroplanes
AD/B737/104 Rudder Power Control Unit Inspection 6/97
Applicability: Main rudder power control units (PCU) that are to be fitted to Model 737 airplanes and which are identified in Boeing Service Letter 737-SL-27-112-B, dated February 6, 1997.
Requirement: To identify, inspect and repair suspect main rudder PCUs prior to fitment to Model 737 aircraft in accordance with the requirements of Boeing Service Letter 737-SL-27- 112-B dated February 6, 1997.
Note: FAA AD 97-05-10 refers.
Compliance: After 90 days of the effective date of this Directive, the requirement is to be completed prior to fitment of a replacement main rudder PCU to an aircraft.
This Airworthiness Directive becomes effective on 22 May 1997.
Background: The FAA has received a report of cracking of the internal summing lever of the main rudder PCU on a model 737 airplane. Investigation showed that a Hi-Lock bolt had been installed in the lever assembly by a repair station instead of the correct specification bolt (Boeing Part No. 66-22749-1). The larger bolt radius of the Hi Lock bolt in the shoulder to shank transition area was such as to create an interference fit with the bearing that caused the inner race of the bearing to crack. Such cracking, if not detected and corrected could lead to seizure of the bearing and possible uncommanded rudder movement. This Directive requires that all replacement main rudder PCUs are inspected before fitment to ascertain if they are suspect and if so to ensure that they have been subject to the corrective action detailed in US FAA AD
97-05-10.
Overview
The Civil Aviation Regulations 1998, under PART 39 - 105, address safety concerns specific to civil aviation operations in Australia. This regulation was enacted by the Australian Parliament to ensure that civil aviation maintains the highest safety standards, and it was introduced to address specific safety gaps identified in aircraft operations. One such instance is AD/B737/104, which pertains to the inspection of rudder power control units (PCU) for Boeing 737 series aeroplanes. This directive was issued in response to reports of cracking in the internal summing lever of the main rudder PCU, a problem identified through investigations following an incident involving an incorrectly specified bolt. The policy objective is to mandate the inspection and repair of suspect rudder PCUs before they are fitted to aircraft, thus preventing potential uncommanded rudder movements that could compromise flight safety.
The directive requires the identification and inspection of main rudder PCUs in accordance with Boeing Service Letter 737-SL-27-112-B, dated February 6, 1997, and references the FAA's AD 97-05-10. Compliance with this directive is mandatory, with a requirement to complete the inspection and repair of suspect PCUs within 90 days of the directive's effective date, which was 22 May 1997. This ensures that any identified issues are rectified promptly, thereby maintaining the airworthiness of the aircraft and enhancing overall aviation safety.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, which pertains to the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, governs the maintenance and inspection of aircraft within Australia. This legislation applies to all main rudder power control units (PCU) that are intended for installation on Boeing 737 series aeroplanes and are identified in Boeing Service Letter 737-SL-27-112-B dated February 6, 1997. The requirement under this legislation is for the identification, inspection, and repair of suspect main rudder PCUs before they are fitted to Model 737 aircraft, following the guidelines outlined in the aforementioned Boeing Service Letter. Compliance with this directive is mandatory, with an effective date set 90 days after the directive's issuance on 22 May 1997. The directive's background indicates a concern over cracking of the internal summing lever of the main rudder PCU due to improper bolt installation, which could result in uncommanded rudder movement. The legislation ensures that all replacement main rudder PCUs are inspected to prevent such issues and align with the corrective actions detailed in the US FAA AD 97-05-10.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, mandates the adherence to Airworthiness Directives (AD) issued by the Civil Aviation Safety Authority (CASA). For Boeing 737 series aeroplanes, AD/B737/104 requires a thorough inspection and repair of the main rudder power control units (PCUs) before they are fitted to these aircraft (section 6/97). This directive is intended to address the specific issue of cracking in the internal summing lever of the main rudder PCU, as identified in Boeing Service Letter 737-SL-27-112-B dated February 6, 1997. The directive mandates that any suspect PCUs must be inspected and repaired to ensure they meet the specifications outlined in the referenced service letter.
The obligations imposed by this AD include the identification of the affected PCUs, conducting a detailed inspection to detect any signs of cracking or other defects, and implementing the necessary corrective actions if defects are found. The directive requires these steps to be completed prior to the installation of any replacement PCUs on Boeing 737 aircraft. Compliance with this directive is expected within 90 days from its effective date, which was 22 May 1997. Non-compliance with this AD could lead to serious safety issues, including potential uncommanded rudder movements, which could compromise the aircraft's safety.
The background of this directive stems from a report of a Hi-Lock bolt being incorrectly installed in the lever assembly of a main rudder PCU by a repair station. This installation error led to a cracking of the bearing's inner race, which could result in bearing seizure and subsequent rudder malfunction. The directive aims to prevent such occurrences by ensuring that all replacement PCUs are inspected and repaired to meet the specified standards. Failure to adhere to these requirements could result in severe consequences, including potential grounding of the aircraft until the issue is rectified.
Under the Civil Aviation Regulations 1998, non-compliance with ADs such as AD/B737/104 could lead to significant penalties. The specific offences and penalties are not detailed within the legislative instrument itself but are generally governed by broader aviation safety laws. Potential consequences may include fines, legal action, or operational restrictions imposed by CASA. The exact penalties could vary depending on the severity of the non-compliance and the impact on aviation safety. The overarching aim of these regulations is to ensure the highest standards of safety are maintained in the aviation industry, thereby protecting both the public and the operators of the aircraft.