AD/PHZL/57 Amdt 2 - Blade Tip Stalling

Overview

The Civil Aviation Regulations 1998, specifically Part 39 - 107, establish stringent safety standards to ensure the airworthiness of aircraft within Australia. The Act was enacted to address safety concerns and to ensure compliance with international civil aviation safety standards. The Civil Aviation Safety Authority (CASA) is the enacting body, and the policy objective is to maintain and enhance the safety of civil aviation operations within Australia by ensuring that aircraft and aviation products meet the required safety standards. This legislative instrument focuses on specific safety directives concerning Hartzell propellers installed on certain Dornier aircraft models, aiming to prevent blade tip stalling that could lead to blade cracking and potential flight safety issues. This particular legislative instrument, AD/PHZL/57 Amendment 2, addresses the problem of blade tip stalling in Hartzell propellers used in Dornier DO-228-100 or 200 aircraft with Garrett engine model TPE-331-5-252D. The amendment mandates specific inspection procedures and intervals to mitigate the risk of blade tip stalling, which can occur during landing runs when using the ‘Beta’ range above 55 KIAS. The requirement is to follow Hartzell Service Bulletin No 140F and Hartzell Service Instruction 167D, with initial inspections mandated within 100 hours of service after 25 February 1988 or by 25 August 1988, whichever comes first. This amendment ensures that the propellers are inspected and maintained according to the latest manufacturer's data, thus safeguarding aircraft safety.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 107, pertains to the Civil Aviation Safety Authority's (CASA) schedule of airworthiness directives, and includes detailed requirements for the inspection and maintenance of certain propellers. This legislative instrument applies to all Hartzell propeller models HC-B4TN-5( ) L/LT 10574(B), HC-B4TN-5( ) L/LT10574A(B), and HC-B4TN-5( ) L/LT10574AS(B) installed on Dornier DO-228-100 or 200 aircraft equipped with a Garrett engine model TPE-331-5-252D. The directive mandates that these propellers must be inspected and maintained in accordance with Hartzell Service Bulletin No 140F and Hartzell Service Instruction 167D, with the aim of preventing blade tip stalling during landing runs, which could otherwise lead to blade cracking due to increased stress. Compliance with this directive requires a daily inspection of the blades as per Hartzell Service Bulletin 140F, and an initial inspection within 100 hours of time in service after 25 February 1988 or by 25 August 1988, followed by reinspections at intervals not exceeding 100 hours of time in service. Pilots are not authorised to certify this inspection unless they hold a Maintenance Authority. This regulation is applicable nationally across Australia and extends to all aircraft registered under the Civil Aviation Act 1988. No exclusions or exemptions are explicitly stated in the directive itself, though compliance with other relevant CASA regulations and manufacturer's instructions may apply. The scope of the directive can be further clarified or expanded through subordinate instruments issued by CASA, which may provide additional guidance or specific amendments to the airworthiness directives.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 107, includes an Airworthiness Directive (AD) concerning Hartzell propellers. The AD (AD/PHZL/57Amdt 2) focuses on blade tip stalling in Hartzell propeller models HC-B4TN-5( ) L/LT 10574(B), HC-B4TN-5( ) L/LT 10574A(B), and HC-B4TN-5( ) L/LT 10574AS(B) installed on Dornier DO-228-100 or 200 aircraft equipped with a Garrett engine model TPE-331-5-252D. The directive requires that actions be taken in accordance with Hartzell Service Bulletin No 140F and Hartzell Service Instruction 167D. Operators of these aircraft must comply with a daily inspection of the propeller blades in accordance with Hartzell Service Bulletin 140F. It is crucial to note that certification of this inspection by pilots is not acceptable unless they hold a Maintenance Authority for this specific purpose. Additionally, operators must conduct a comprehensive inspection within 100 hours of time in service after 25 February 1988 or by 25 August 1988, whichever comes first, and then reinspect at intervals not exceeding 100 hours of time in service thereafter. The directive is based on the risk of blade tip stalling during the landing run when the aircraft speed exceeds 55 knots indicated airspeed (KIAS) in the ‘Beta’ range. This condition can lead to higher than normal blade stresses, potentially causing cracking of the propeller blades. The AD was amended to incorporate the latest edition of the manufacturer’s data, which modifies the blade tip inspection area, and to reflect the manufacturer's requirements that exclude certain blade models from the directive’s applicability. Failure to comply with the requirements set forth in this AD could result in serious safety hazards. The Civil Aviation Safety Authority (CASA) enforces strict adherence to these directives to maintain the airworthiness of aircraft and ensure the safety of passengers and crew. Non-compliance may lead to enforcement actions, including fines, suspension or revocation of the aircraft's airworthiness certificate, and potential criminal charges if the non-compliance results in accidents or other safety incidents. The exact penalties for non-compliance are determined by CASA and can vary based on the severity and circumstances of the breach.