Overview

The Civil Aviation Safety Authority (CASA) introduced Airworthiness Directive (AD) S-76/69 in 2002 to address the safety concern of main rotor blade damage in Sikorsky S-76 series helicopters due to lightning strikes. This AD was enacted following an investigation into an in-flight failure of a main rotor blade caused by lightning damage, which led to the loss of the helicopter. The policy objective of this directive is to ensure the continued airworthiness of the affected helicopters by mandating specific actions to be taken to prevent further incidents of this nature. CASA issued this directive under subregulation 39.1(1) of the Civil Aviation Regulations 1998, requiring helicopter operators to review blade service records, remove blades with evidence of lightning damage, and adhere to specific instructions to mitigate the risk of in-flight failures.

Scope and Application

The Airworthiness Directive (AD) F2006B06745, issued under subregulation 39.1(1) of the Civil Aviation Regulations 1998 by the Civil Aviation Safety Authority (CASA), specifically applies to Sikorsky S-76A, B, and C series helicopters. The directive mandates certain actions to address the issue of main rotor blade damage caused by lightning strikes, aiming to rectify an unsafe condition identified after an in-flight failure of a rotor blade due to such damage. This AD applies to all operators of the specified helicopter models within the Commonwealth of Australia. The requirements set forth include a review of blade service records to identify any lightning strike damage, the removal of any blades damaged by lightning before further flight, and the removal of blades with specific serial numbers known to have sustained such damage. Furthermore, if the blade history cannot be determined, the blade must be removed from service, and any blade damaged by a lightning strike must also be removed before further flight. Compliance with these directives must occur before further flight following specific dates mentioned in the AD. The AD becomes effective from 30 July 2002, as notified in the Commonwealth of Australia Gazette on that date.

Key Provisions

The main operative sections of this Airworthiness Directive (AD) under the Civil Aviation Regulations (CAR) 1998, issued by the Civil Aviation Safety Authority (CASA) delegate, pertain to Sikorsky S-76 Series Helicopters. Section 1 of the AD (section 1) requires a review of blade service records and other relevant records for evidence of damage due to lightning strikes. This review must be conducted in accordance with the instructions in paragraphs 3.A.(1), (2), and (3) of the Sikorsky Aircraft Corporation Alert Service Bulletin No. 76-65-55A dated 25 July 2002. Section 2 (section 2) mandates the removal of any blade identified as damaged by a lightning strike before further flight. Section 3 (section 3) necessitates the removal of specific blades with serial numbers listed due to known lightning damage. Section 4 (section 4) instructs that if the history of a blade cannot be determined, it should be removed from service. Additionally, if a blade is found to have sustained lightning strike damage, it must be removed from service before further flight. The AD imposes several obligations and requirements on the parties governed by it. Firstly, operators of Sikorsky S-76A, B, and C helicopters must conduct a thorough review of the blade service records and other pertinent records to identify any damage caused by lightning strikes. This review must be executed as per the instructions provided in the Alert Service Bulletin. Secondly, if a blade is identified as damaged by a lightning strike, it must be removed from service before any further flight. Thirdly, specific blades listed in the AD must be removed from service regardless of their service records. Lastly, if the history of a blade cannot be determined, it must also be removed from service. These requirements are designed to ensure the airworthiness and safety of the helicopter operations. Breach of the requirements set out in this Airworthiness Directive may result in various civil and criminal consequences. Non-compliance with the AD could lead to the aircraft being deemed unairworthy, which may result in enforcement actions by CASA. Such actions could include the grounding of the aircraft until the required actions are taken, fines, and potentially legal proceedings. The specific penalties for non-compliance are not detailed in the AD itself, but they could include substantial fines and imprisonment as prescribed under the Civil Aviation Act 1988 and other relevant legislation. The seriousness of the potential consequences underscores the importance of adhering to the AD to ensure the continued safety and airworthiness of the Sikorsky S-76 Series Helicopters.