300 times around the world: Before a commercial aircraft engine is overhauled for the first time, it covers some 12 million kilometres. With experience, expertise and precision, we ensure that it continues to run reliably.
Vertical engine dismantling
In our workshop, the Repair and Overhaul Shop, the careful dismantling of each engine into its individual components takes place. During the initial inspection, the engine is first examined for any hidden damage.
Subsequently, all non-modular parts, e.g. pipes, are removed. Then a crane moves the engine to a vertical position. This vertical method, which is unique to N3, allows a material-friendly disassembly of the engine modules. The mechanics work particularly efficiently and ergonomically on all four engine types with the help of special electronically-operated lifting platforms. The modules are subsequently disassembled into their individual parts or into their module disassembly sections.
The heart of the area is the cleaning plant, with a total of 28 cleaning tanks for degreasing, descaling, paint stripping and rust removal. Each tank comprises around twelve and a half cubic metres and allows components with a diameter of up to 2 metres in diameter and weighing up to 500 kg to be machined.
The entire cleaning area is sealed. The exhaust air is extracted and prepared in the cellar for reuse. The process water remains in the cleaning line and is used several times by a multi-stage rotation. The addition of several blast machines and flexible manual workstations make the individually customised cleaning of virtually all components possible.
Following the cleaning process, our staff inspect the engine parts for any damage. Non-Destructive Testing (NDT) procedures are then used. These include, among others, Fluorescent Penetrant Inspection (FPI), Magnetic Particle Inspection (MPI) and X-ray.
For particularly critical engine components, such as the blades or welding seams, other methods of non-destructive testing are established: While FPI, MPI and X-ray analysis are based on the evaluation of the user's experience and the trained eye, turbulent flow and ultrasonic tests provide an accurate measurement result.
Here, all engine parts and components are compared with the permissible limits and assessed for their reusability and/or reparability. Based on the damage that is found, our staff select necessary repair processes, taking account of technical and economic aspects.
In findings reports, they document all wear patterns with the greatest degree of accuracy. If a part is intact, it is directed to the "Provision" area. If a repair is necessary, the corresponding part is transported to the N3 internal repair workshop or shipped for external processing and repair. We keep the replaced parts in our warehouse until proper disposal is available.
In addition to the maintenance of all engine components, N3 also performs repairs up to new part quality. We also perform reliable individual repairs for international customers.
After the inspection, the decision is made whether the part has to be replaced, repaired or overhauled. Our repair planners convert each order into detailed workflows, observing the legal requirements and the manufacturing specifications. We guarantee our customers a fast and reliable implementation.
Our state-of-the-art machinery allows complex overhauls, repairs and modifications to be carried out in their entirety. Detailed information on all repair processes can be found here.
Module assembly, balancing and grinding
All parts - undamaged, new and repaired - are assembled individually for the assembly of the engine. The mechanics assemble the modules, grind and balance them, and after internal inspection pass them on to the engine assembly.
The grinding of the rotor tips by means of a high-speed grinding machine optimises the gap between rotor and stator (housing). As a result, the efficiency of the engine is improved and its kerosene consumption is reduced.
Given that even the smallest imbalances can lead to strong vibrations in the system at certain frequencies, N3 also performs the balancing of the high-speed rotating engine turbines and compressors. This will increase their service life and ultimately improve the safety of the engines.
Engine assembly and approval
The final assembly of the engine is also carried out in vertical suspension. It requires the utmost discipline, as even the slightest damage can render an expensive engine part unusable. For this reason, here at N3 we work according to the most modern quality assurance procedures: Every process and every assembled part is checked and recorded in the assembly documents. Continuous control measurements and the simultaneous execution of additional visual examinations in accordance with the principle of dual control ensure further protection.
After the assembly of the entire engine, the authorised personnel check all the maintenance steps carried out and compare them with the customer specifications, work plans and manufacturer requirements.