AD/BEECH 1900/19 - Under Torqued Propeller Mounting Bolts

Overview

The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority (CASA) and enacted by the Australian Parliament, encompass a range of safety directives to ensure the safe operation of aircraft within Australia. One such directive, AD/BEECH 1900/19, targets a specific issue with under-torqued propeller mounting bolts in Beechcraft 1900 Series aeroplanes, particularly model 1900D aircraft. This directive was introduced to address the risk of fatigue cracking in the propeller mounting bolts, which could lead to the loss of a propeller. Compliance with this directive is mandated to mitigate the identified safety risk, with checks and corrective actions required within 50 hours of the directive's issuance on 24 September 1997.

Scope and Application

The Civil Aviation Regulations 1998, as amended, pertain to the operation and maintenance of aircraft within Australian airspace and are enforced by the Civil Aviation Safety Authority (CASA). Specifically, Part 39 - 105 addresses the issuance of Airworthiness Directives, which are mandatory requirements designed to ensure the safety of aircraft operations. The directive AD/BEECH 1900/19 applies to Beechcraft 1900 Series aeroplanes, particularly Model 1900D aircraft with specified serial numbers that have not undergone specific propeller maintenance procedures since their original installation. The directive mandates that the propeller mounting bolts be checked for correct torque settings as per the manufacturer's guidelines, with bolts torqued to less than 60 ft-lbs needing replacement and those at 60 ft-lbs or greater requiring re-torqueing according to the specified procedures. Compliance with this directive is mandatory within 50 hours time in service from the directive's effective date of 24 September 1997, and failure to adhere to these requirements can result in significant safety risks, including potential propeller failure. This directive extends to ensuring that all relevant aircraft maintain the specified safety standards to prevent incidents related to under-torqued propeller mounting bolts.

Key Provisions

The Civil Aviation Regulations 1998, particularly Part 39 - 105, mandate specific safety directives for certain Beechcraft 1900 Series Aeroplanes, focusing on the critical issue of under-torqued propeller mounting bolts (AD/BEECH 1900/19). According to this directive, it is imperative that the propeller mounting bolts on applicable Model 1900D aircraft, specifically those with serial numbers UE176 through UE280, UE282, and UE284, are inspected and adjusted if necessary. The requirement is that these bolts must adhere to the correct torque figures as specified in Raytheon's urgent action letter number 52-0092 dated 22 July 1997. If any mounting bolt is found to have a torque setting of less than 60 foot-pounds, it must be replaced before any further flight. Conversely, if the torque setting is 60 foot-pounds or greater, the bolts should be re-torqued following the manufacturer’s procedures to ensure safety. Operators and owners of the affected aircraft must ensure compliance with this directive within the next 50 hours of time in service (TIS) following the directive's effective date, which is 24 September 1997. This directive is a response to reports received by the FAA, indicating that certain Raytheon model 1900D airplanes had been installed with propeller mounting bolts that were under-torqued. This condition has the potential to cause fatigue cracking of the bolts, which could ultimately result in the loss of a propeller. Thus, the primary obligation for the governed parties is to conduct the necessary inspections and adjustments to prevent any risk of such a critical failure. Failure to comply with this directive can lead to serious consequences. The primary risk is the potential for in-flight failure of the propeller mounting bolts, which could result in an emergency situation, potentially leading to loss of control of the aircraft. The regulatory framework imposes stringent obligations on aircraft operators and owners to ensure that all necessary checks and adjustments are performed within the specified timeframe. Non-compliance with these safety directives can result in significant civil and criminal penalties under the Civil Aviation Act 1988. The maximum penalties for non-compliance can include substantial fines and, in severe cases, criminal charges that could lead to imprisonment. The exact penalties depend on the severity of the breach and the impact on aviation safety.