AD/F50/73 - Hub Mounting Face Dowel Hole Inspection Following Propeller Overtorque

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, address various aspects of civil aviation safety, including the establishment of airworthiness directives to ensure the safety of aircraft operations. One such directive, AD/F50/73, was introduced to specifically tackle the problem of propeller overtorque incidents in Fokker F27 Mk 50 series aircraft equipped with certain Dowty propellers. This directive was issued by the Civil Aviation Safety Authority to ensure that any occurrence of propeller overtorque is followed by an inspection as per the manufacturer's specified procedures, thereby mitigating the risk of further incidents and ensuring continued airworthiness of the affected aircraft.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, establish the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, which applies to all Fokker F27 Mk 50 series aircraft fitted with specific Dowty propellers. This legislation mandates that whenever a propeller is subject to an overtorque condition, as defined in the relevant Dowty Aerospace Mandatory Service Bulletin, operators must inspect the propeller in accordance with the reference Service Bulletin. The directive is in place to address reported incidents where propellers have been overtorqued during operational use, thereby ensuring the safety of the aircraft and its passengers. Compliance is required whenever an overtorque condition is encountered. The directive became effective on 27 March 1997, and it superseded previous directives such as RLD AD 89-079/3 and UK CAA AD 023-05-89, reflecting ongoing efforts to enhance aviation safety standards.

Key Provisions

The main operative sections of the Civil Aviation Regulations 1998, specifically Part 39 - 105 concerning the Civil Aviation Safety Authority Schedule of Airworthiness Directives, detail specific requirements for Fokker F50 (F27 Mk 50) series aeroplanes, notably AD/F50/73 (section 39-105-73). This directive mandates that whenever a propeller on a Fokker F27 Mk 50 series aircraft fitted with specified Dowty propellers experiences an overtorque condition, a thorough inspection of the propeller must be conducted. This inspection must adhere to the procedures outlined in Dowty Aerospace Mandatory SB F50-61-50 Revision 7 dated December 12, 1996. The directive references previous directives and notifications, including RLD AD 89-079/3 dated December 31, 1996, which supersedes RLD AD 89-079/2 dated November 24, 1994, and UK CAA AD 023-05-89. The directive became effective on March 27, 1997. The obligations imposed by this Act on the parties or entities it governs include ensuring that any occurrence of an overtorque condition on the specified propellers is immediately followed by a detailed inspection. The inspection must be conducted in accordance with the specified procedures from the referenced service bulletin. Operators of the affected aircraft must be vigilant in identifying overtorque conditions and must ensure that the necessary inspections are performed by qualified personnel. This ensures the continued airworthiness of the propellers and the overall safety of the aircraft operations. Failure to comply with this Airworthiness Directive can result in significant civil and criminal consequences. While the specific penalties for non-compliance are not detailed within the directive itself, under general aviation safety regulations, breaches can lead to severe penalties. These can include substantial fines and potential criminal charges for operators who fail to adhere to airworthiness directives. Additionally, non-compliance could lead to grounding of the affected aircraft, which can have serious operational and financial repercussions for the airline or operator.