AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/HILLER 12/34 and issues the following AD under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.
Hiller UH-12 Series Helicopters
AD/HILLER 12/34
Amdt 1
Main Transmission Oil Filter 4/2002
Applicability: All UH-12 series helicopters, including Soloy Conversions, incorporating a main transmission part number (P/N) 23500-3, 237700-3, -5, -7, -9, -21 and –23.
Requirement: Inspect the main transmission oil filter and if applicable, the magnetic particle chip detector, in accordance with Hiller Aviation Service Bulletin UH-12-23-2.
Note: FAA Airworthiness Directive 81-17-03 refers.
Compliance: 1. Main transmissions not incorporating Rogerson Hiller Corporation Service Bulletin UH-12-23-3: Unless previously accomplished; within 25 hours’ time in service after this Directive is effective and thereafter at intervals not to exceed:
- Piston engine helicopters: 55 hours.
b. Turbine engine helicopters: 27.5 hours.
2. Main transmissions incorporating Rogerson Hiller Corporation Service Bulletin UH-12-23-3: Unless previously accomplished, within 25 hours’ time in service after this Directive is effective and thereafter at intervals not to exceed:
- Piston engine helicopters: 110 hours.
b. Turbine engine helicopters: 55 hours.
This Amendment becomes effective on 18 April 2002.
Hiller UH-12 Series Helicopters
AD/HILLER 12/34 Amdt 1 (continued)
Background: This Directive was originally issued to require monitoring of the main transmission oil filter. The requirement was in response to reports of extensive wear in the planetary assemblies. This amendment introduces extended compliance intervals for helicopters incorporating a modified main transmission and provides an extended compliance to assist maintenance scheduling..
Eugene Paul Holzapfel
Delegate of the Civil Aviation Safety Authority 10 March 2002
Overview
The Civil Aviation Safety Authority (CASA) issued the Airworthiness Directive (AD) AD/HILLER 12/34, Amdt 1, on 10 March 2002, to address safety concerns related to the main transmission oil filters in UH-12 series helicopters, including Soloy conversions, with specific part numbers. This AD revokes the previous directive AD/HILLER 12/34 and aims to rectify the unsafe condition identified in the original directive through the inspection of the main transmission oil filter and, if applicable, the magnetic particle chip detector. The policy objective is to ensure the safe operation of these helicopters by extending the compliance intervals to aid in maintenance scheduling, particularly for those helicopters with modified main transmissions.
The AD became effective on 18 April 2002, with specific compliance intervals set for piston and turbine engine helicopters based on whether they incorporated a modified main transmission. The intervals were extended to assist in maintenance scheduling and to respond to reports of extensive wear in the planetary assemblies. The directive references FAA Airworthiness Directive 81-17-03, indicating a collaborative approach to aviation safety between Australian and US authorities.
Scope and Application
The Airworthiness Directive (AD) AD/HILLER 12/34 issued under the Civil Aviation Safety Authority (CASA) concerns the main transmission oil filter of all UH-12 series helicopters, including Soloy Conversions, that incorporate specified main transmission parts. The directive applies to these helicopters irrespective of their engine type, whether piston or turbine. The AD mandates inspections of the main transmission oil filter and, if applicable, the magnetic particle chip detector, in line with the instructions outlined in Hiller Aviation Service Bulletin UH-12-23-2. The compliance intervals are differentiated based on whether the main transmission incorporates a specific service bulletin. For transmissions not incorporating Rogerson Hiller Corporation Service Bulletin UH-12-23-3, inspections must occur within 25 hours of the directive's effective date and then at intervals not exceeding 55 hours for piston engine helicopters and 27.5 hours for turbine engine helicopters. For transmissions that do incorporate the service bulletin, the intervals extend to 110 hours for piston engine helicopters and 55 hours for turbine engine helicopters. This amendment extends the compliance intervals to facilitate better maintenance scheduling and was prompted by reports of excessive wear in the planetary assemblies. The AD revokes the previous directive AD/HILLER 12/34 and comes into effect on 18 April 2002.
Key Provisions
The Airworthiness Directive (AD) AD/HILLER 12/34 Amdt 1, issued under subregulation 39.1 (1) of the Civil Aviation Regulations 1998, applies to all UH-12 series helicopters, including Soloy conversions, that incorporate a main transmission part number 23500-3, 237700-3, -5, -7, -9, -21 and -23. The directive mandates an inspection of the main transmission oil filter, and if applicable, the magnetic particle chip detector, in accordance with Hiller Aviation Service Bulletin UH-12-23-2. The directive references FAA Airworthiness Directive 81-17-03 for further guidance. The requirement is to inspect the main transmission oil filter within 25 hours’ time in service after the directive becomes effective, and thereafter at specific intervals depending on whether the helicopter is piston or turbine engine powered.
The obligations imposed by this directive require that the specified inspections be conducted by authorised personnel, adhering to the outlined intervals. For piston engine helicopters, the intervals are set at 55 hours for transmissions not incorporating Rogerson Hiller Corporation Service Bulletin UH-12-23-3, and 110 hours for those that do. For turbine engine helicopters, the intervals are 27.5 hours and 55 hours, respectively. These inspections must be carried out in line with the instructions provided in the directive and the referenced service bulletin.
Failure to comply with the requirements of this Airworthiness Directive may result in significant safety risks. Although the directive itself does not explicitly state penalties for non-compliance, non-compliance with Civil Aviation Regulations 1998 can lead to enforcement actions by the Civil Aviation Safety Authority (CASA). Such actions may include fines, suspension or revocation of airworthiness certificates, and other regulatory sanctions. Furthermore, non-compliance may lead to aircraft being grounded, which could result in operational disruptions and financial losses. The directive aims to ensure the continued airworthiness and safety of the UH-12 series helicopters, and thus adherence to its provisions is critical.