COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Enstrom F-28 Series Helicopters
AD/ENST 28/35 Inadvertent Trim Motor Operation 2/94
TX
Applicability: All F-28C, F-28C-2, F-28F, 280C, 280F and 280FX series helicopters equipped with a 24 volt DC electrical system.
Requirement: 1. Inspect and modify the trim system in accordance with Enstrom Helicopter Corporation Service Directive Bulletin 0082 Revision A dated 18 March 1993.
2. Inspect the trim system in accordance with Enstrom Helicopter Corporation Service Directive Bulletin 0082 Revision A dated 18 March 1993.
Note: FAA Priority Letter AD 93-12-14 issued 6 December 1993.
Compliance: 1. Within five hours time in service from 13 December 1993.
2. At intervals not to exceed 100 hours time in service or at each annual inspection, whichever occurs first.
Background: There have been three reports of inadvertent trim motor operation as a result of sticking relays. A stuck relay causes the trim motor to rapidly deploy to the full trim position, resulting in high cyclic control forces that significantly reduce the controllability of the helicopter and possibly lead to total loss of control.
Overview
The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority, include Part 39 - 105 which deals with the Schedule of Airworthiness Directives. This particular legislative instrument, F2006B09592, was introduced to address the problem of inadvertent trim motor operation in specific Enstrom F-28 series helicopters, a safety concern identified through reports of sticking relays causing the trim motor to rapidly deploy. This issue significantly reduces the controllability of the helicopter and can potentially lead to total loss of control. The policy objective of this legislative instrument is to mandate inspections and modifications of the trim system in accordance with specified service directives, ensuring the airworthiness and safety of the affected helicopters.
The regulation applies to all F-28C, F-28C-2, F-28F, 280C, 280F, and 280FX series helicopters equipped with a 24 volt DC electrical system. It requires compliance within five hours of service from 13 December 1993, and subsequent inspections at intervals not exceeding 100 hours of service or at each annual inspection, whichever comes first. This directive aims to mitigate the risk associated with the identified safety hazard by ensuring that all affected helicopters undergo the necessary inspections and modifications as per the specified guidelines.
Scope and Application
The Civil Aviation Safety Authority Schedule of Airworthiness Directives, as detailed in the Civil Aviation Regulations 1998, applies specifically to the Enstrom F-28 series helicopters, encompassing models F-28C, F-28C-2, F-28F, 280C, 280F, and 280FX, provided they are equipped with a 24 volt DC electrical system. This regulation is concerned with the inadvertent operation of the trim motor, a safety issue that has arisen due to sticking relays causing rapid deployment of the trim motor to full position, which in turn leads to high cyclic control forces and potential loss of control. The directive mandates that the trim system must be inspected and modified as per Enstrom Helicopter Corporation Service Directive Bulletin 0082 Revision A dated 18 March 1993. Compliance with these requirements must occur within five hours of the directive's issuance date of 13 December 1993, and subsequently at intervals not exceeding 100 hours of time in service or during each annual inspection, whichever comes first. The directive applies nationally under the Commonwealth of Australia, and its enforcement ensures the maintenance of safety standards in civil aviation.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39, Section 105, mandates the compliance of all F-28C, F-28C-2, F-28F, 280C, 280F, and 280FX series helicopters equipped with a 24-volt DC electrical system with the Airworthiness Directive AD/ENST 28/35. This directive pertains to inadvertent trim motor operation, aiming to mitigate risks associated with sticking relays that could cause the trim motor to operate unexpectedly. The primary requirement (Section 1) is for the inspection and modification of the trim system as outlined in the Enstrom Helicopter Corporation Service Directive Bulletin 0082 Revision A dated 18 March 1993. A supplementary requirement (Section 2) mandates a further inspection of the trim system following the initial modification, also in accordance with the same service bulletin and note referencing the FAA Priority Letter AD 93-12-14 issued on 6 December 1993.
Operators of the specified helicopters must ensure that the trim system modifications and inspections are conducted within five hours of the helicopter's time in service from 13 December 1993. Moreover, ongoing compliance requires that the inspections be repeated at intervals not exceeding 100 hours of time in service or at each annual inspection, whichever comes first. These provisions are designed to maintain the safety and airworthiness of the helicopters by addressing the identified issue of inadvertent trim motor operation, which could compromise controllability and potentially lead to a loss of control.
Failure to comply with the Airworthiness Directive AD/ENST 28/35 can result in serious consequences. Under Section 237 of the Civil Aviation Act 1988, operators found to be in breach of these regulations may face civil penalties. The maximum penalty for contravening these regulations includes fines of up to $165,000 for a body corporate and $33,000 for an individual. Additionally, in the event that non-compliance results in an aviation occurrence, the penalties can escalate further, potentially including imprisonment. The seriousness of these consequences underscores the importance of adhering to the outlined safety directives to prevent accidents and ensure the safety of all personnel involved.