Turbomeca engines are widely used in the helicopter industry. There are two engine families: the Arrius and the Arriel. These engines operate primarily in the single and twin, light and medium helicopter segments.
The required maintenance steps are determined by the operator, taking into account the level of maintenance they want to perform, personnel and logistic considerations. Arriel engines work well in our Emergency Helicopter Service (HEMS) industry due to their modular concept and the high demand of dispatch reliability. These engines are free turbine turboshaft engines with forward power drive. The module concept is key to what makes this engine easy to maintain.
Before attempting to perform maintenance on these engines, it is imperative to understand some important features and the use of the engine’s technical documentation. In general, there are three parts to the technical documentation.
The first part is the Operation documents:
These are the control documents:
• Aircraft Flight Manual (AFM)
• Management documents (e.g. engine log book)
The second part is the Maintenance documents:
• Maintenance manual
• Service bulletins
• Service letters
• Modification index
• The third part is the Identification documents:
• Maintenance documents
• Spare parts catalogue
• Special tool catalogue
• Overhaul and repair documents
• Illustrated parts catalogue
• Descriptive list and drawings
T urbomeca engine maintenance procedures are divided into four levels as follows: First Level Line Maintenance (O), Second Level Line Maintenance (I), Third Level Line Maintenance (H) and Fourth Level Line Maintenance (D).
First Level Line Maintenance (O) includes check and servicing procedures, preventative maintenance procedures and corrective or unscheduled maintenance. This includes removing and replacing the Line Replaceable Unit (LRU) and installation procedures. This level of maintenance is done in the field by the helicopter operator.
Second Level Line Maintenance (I) is done with the engine removed from the airframe. This may be scheduled or unscheduled and include module removal or installation and/or Shop Replaceable Units (SRU). The Turbomeca engine is divided into five modules that can be replaced or repaired on site. They are:
• M01: Transmission Shaft and Accessory Gearbox
• M02: Axial Compressor
• M03: Gas Generator High Pressure Section
• M04: Power Turbine
• M05: Reduction Gearbox
Third Level Line Maintenance (H) is carried out on removed major parts of each module. It consists of replacement or reconditioning of subassemblies without repair or adjustment. This level of maintenance can be carried out on site by the operator, provided the operator has successfully completed the formal training required and has the official updated documentation in their possession.
Fourth Level Line Maintenance (D) is carried out when the engine or module has reached the end of its Time Between Overhauls (TBO).
This information is offered to increase awareness of the different levels of maintenance that can be performed on these engines. With the proper training and tooling, the helicopter engine specialist will appreciate the modular concept of Turbomeca engines.