PYLON WITH ENGINE ASSEMBLY

This application claims the benefit of the filing date of the Chinese Patent

Application No. 200610083466.8 filed May 30, 2006, the disclosure of which is hereby incorporated herein by reference.

The present invention is related to the field of airplane assembly. In particular, the present invention is directed to a method for assembling and/or disassembling an airplane engine unit to a wing of an airplane, the engine unit comprises an engine and a pylon.

In today's commercial aircraft industry short delivery times of the airplanes have become more an more important. Shorter delivery times thus require an adaptation and streamlining of the production and assembly processes in aircraft industry.

However, the high quality and regulatory standards in this industry require intensive testing of the produced and assembled products. To allow for the required testing time on the one hand, and for shorter lead time on the other hand, an improved method of assembly for the engine unit to the wing is desired. If certain testing time is required, this requirement may often limit the possibilities in lead time reduction of production and assembling processes.

In particular, the assembly of an engine unit to the airplane wing today requires several assembly steps. Initially the different parts of the airplane engine unit are assembled step by step to the wing of the airplane. In the final assembly of the engine unit to the airplane's wing, typically first the pylon is mounted to the wing. The pylon is the engine hoisting system for the aircraft's wing. After the pylon is mounted to the wing, the pylon is supplied with the customary equipment such as a fire extinguisher reservoir, etc. Subsequently, the engine is mounted to the assembled sub-unit of pylon and wing. Once the engine is mounted to the pylon, system connections are installed. The system connections include any supplies such as

pneumatic, hydraulics, fuel, electrical equipment, fire extinguisher and the like. Of course, after these connections have been established, intensive testing is required to ensure that all functions are working and no malfunction of any of these connections occurs. The complete assembly and testing of the connections may take up to several days in the final airplane assembly.

After testing of the connections has been completed, further components like the nacelle are assembled to the unit. The nacelle typically comprises a cowling of the engine and a

reverser. After completion of this step, further testing of the complete system including engine, pylon, wing, connections and nacelle is required.

Since these assembly steps are all performed directly at the wing of the airplane, which is already connected to the fuselage, it is apparent the any problems in assembly and/or testing of any of these part may slow down the production of the aircraft and thus may even increase the overall lead time.

In case errors or malfunction occur during testing or any routine maintenance work on the engine unit, the disassembly of the required the complete removal of any connections, nacelle, engine, pylon from the wing to correct or repair the malfunction and/or errors. It is apparent for a person skilled in the art that this process is time consuming and may slow down the production / maintenance of the airplane or engine.

Since the procedure described above has to be followed in every assembly of an engine unit during production / assembly of a new airplane as well as during every

maintenance of the engine unit, there is a need for an improved assembly and disassembly method for engine units to the wing of an airplane.

It is an object of the present invention to provide an improved assembly and disassembly method for airplane's engine units.

It is a further object of the present invention to provide an assembly / disassembly method for engine units which allows for reduced lead times.

It is yet another object of the invention to provide a method which allows for testing of pre-assembled subunits of the engine unit parallel to earlier airplane assembly steps.

The present invention is directed to a method for assembling and/or disassembling of a airplane engine unit to a wing of an airplane, the engine unit comprising an engine and a pylon, wherein the method comprises the steps of: pre-assembling the engine and the pylon to a pre-assembled sub-unit; and mounting the pre-assembled sub-unit to the wing.

Even though the present invention refer to the assembling and/or disassembling of an engine unit, it is apparent for a skilled person that the invention may also be transferred to any assembling methods in the industry, which may allow pre- assembling and/or testing of the pre-assembled units.

The term "engine unit" as used herein means an pre-assembled unit comprising an engine and a pylon and further optionally a nacelle and/or the connections for various supplies. The engine-unit may also be referred to as "pylon with engine".

The nacelle may further comprise a reverser, a rear and/or outside reverser cowling, an air inlet, a nozzle and/or a cowling for the engine.

The term "engine" as used in the present invention refers to a combination of the either one of the components a cowling, a reverser, a nozzle, an air-inlet or an engine itself.

The term "pylon with engine" as used herein means a pre-assembled unit of a pylon and an engine which is also referred to as a pre-assembled sub-unit.

The method according to the present invention may allow for the reduction of the overall lead time of the production of an airplane.

In particular, the present invention allows for the reduction of the lead time due to the possibility of parallel work flows and/or work packages to the airplane assembly known in the art.

In an exemplary embodiment of the invention the testing of pre-assembled sub-units of the pylon with engine is performed before the respective sub-unit is mounted to the wing in the final production phase of the airplane.

In an exemplary embodiment of the invention the pylon is equipped with customary equipment such as a fire extinguisher reservoir. The "equipped" pylon is then connected with the engine to form the "pylon with engine". In another exemplary embodiment of the invention the pylon with engine may further comprise a cowling.

In a further exemplary embodiment the pylon with engine may also further comprise a nacelle and/or a reverser.

The pre-assembled pylon with engine can be equipped with the necessary connections such as to pneumatic, hydraulics, fuel, bleed, steps an gaps, electricity and/or fire extinguisher to allow for testing of the pre-assembled sub-unit.

In an exemplary embodiment of the invention, the gaps and steps are only adjusted once at the pylon and thus allows for omitting further process steps such as the application of an A-frame (e.g. a dummy for prejustment).

In an exemplary embodiment of the invention the testing of the pylon with engine is performed in a separate assembly unit which may also comprise a stand alone test stand. Thus, the testing of the functions of the pylon with engine may be performed without being mounted to the wing of the airplane.

The testing in a separate assembly unit allows for testing of the pre-assembled pylon with engine sub-unit parallel to other production process steps of the airplane, which have to be finalized before the engine unit is to be installed to the wing of the airplane and testing of the completely wing-mounted engine unit was possible according to the process known in the art. In other words, the present invention allows for the shifting of testing into earlier and/or parallel assembly steps of the airplane.

The parallel testing alone thus allows for a reduction of the lead time of the airplane.

Further, in case that errors or malfunctions within any one of the parts of the pylon with engine or the connections occurs during testing, the present invention allows for a shorter repair/maintenance time as the pylon with engine as the pre-assembled sub- unit does not need to be disconnected from the airplane's wing before repair. In

addition, the connections between e.g. the fuel supply from the wing etc. do not need to be disconnected which may further speed up the disassembly / re-assembly.

In an exemplary embodiment, the testing of the pre-assembled sub-unit, preferably the pylon with engine does allow for parallel testing of dry runs, wet runs and/or destorage runs to other, earlier assembly steps of the airplane.

Once the testing of the pre-assembled sub-unit has been successfully completed, the pre-assembled sub-unit is mounted to the wing of the airplane.

The tested and pre-assembled sub-unit can be transported to the position of assembly to the wing by any method known to a person skilled in the art, e.g. a transportshuttle.

The installation of the pylon with engine can be performed by any method known to the person skilled in the art. In an exemplary embodiment the installation of the pre- assembled pylon with engine is done via a sling-hoisting gear. The installation with a sling-hoisting gear allows for exact positioning of the pylon with engine subunit due to its free-running characteristics.

In an another exemplary embodiment, the installation of the pre-assembled sub-unit, in particular the pylon with engine, may be done with the help of a positioner. In a further exemplary embodiment the positioner is an engine positioner which may be positioned on the assembly floor.

In an exemplary embodiment of the invention the positioner is able to move in all six dimensional axes and the direction of movements and centers of rotation can be arbitrarily defined. In another exemplary embodiment of the invention the positioner

exhibits a positional accuracy within the required tolerances. Further, in yet another exemplary embodiment of the invention, the positioner is automotive and is able to move in diagonal and traverse directions. The positioner may also be equipped with universal interfaces for removable and transport frames.

In yet another embodiment of the invention the positioner may be equipped with sensor for measuring the current load and the position of the load relative to the wing to allow for controlling the load and the positioner.

In another exemplary embodiment of the invention, the positioner is programmable to carry out pre-programmed movements in all three dimensions. This allows for a very precise, "shock-free" and soft movement of the pre-assembled sub-unit to be installed to the airplane's wing.

In a further exemplary embodiment of the invention, the positioner may further be able to determine the exact position and angles of the parts and/or sub-units to be installed and connected via an optical measurement system such as a laser tracking and/or fotogrammetry system.

Those skilled in the art will readily appreciate that the method of moving the positioner for the mounting of the pylon with engine to the wing may be embodied as computer program, i.e. by software, or may be embodied using one or more special electronic optimization circuits, i.e. hardware, or the method may be embodied in hybrid form, i.e. by means of software components and hardware components.

The program element according to an exemplary embodiment of the invention may preferably be loaded into working memories of a data processor. The data processor may thus be equipped to carry out exemplary embodiments of the methods of

mounting the pylon with engine. The computer program may be written in any suitable programming language, such as, for example C++ any may be stored on a computer readable medium, such as a CD-ROM. Also, the computer program may be available from a network, such as the Worldwide Web, from which it may be downloaded into image processing units or processors, or any suitable computers.

The pylon to wing junction is provided by a wing spigot, which transfers the thrust from the engine into the airplane structure, and by attachment lugs at the front and rear area of the wing, which are holding the pylon.

The spigot is mounted in a defined angle almost perpendicular to the plane of the wing and thus the installation of the pylon may be difficult if the pylon approaches the spigot in a wrong angle. This may lead to blocking of the pylon and installation of the pylon may be complicated or the pylon may need to be removed from the spigot before a new installation has to be started. In some case, the blocking may also lead to a damage of either the spigot (and thus the wing) or the pylon or both.

By using a positioner which reveals the above-mentioned characteristics, the "spigot- problematic", i.e. the blocking during installation of the pylon may be prevented.

In an exemplary embodiment, the present invention provides a method wherein the blocking of the spigot with the bearing sleeve is minimized by the positioning of the pre-assembled sub-unit by the positioner.

A further benefit of the present invention may be that testing in a separate assembly unit and/or a stand alone test stand may allow for keeping legal requirements which may become more and more strict in the future. Since "closed" test stands which are able to include a completely assembled airplane fuselage and wing(s) require large

space, it may be easier to provide suitable test facilities which allow for "closed" testing of the pylon with engine sub-unit. Thus, facilitating testing without the installation of the pylon with engine to the wing of the airplane may also reduce noise exposure and/or unpleasant odor for employees and/or the environment. Further, the method of the present invention may also be suitable to reduce pollution by more effective and efficient testing.

These and other aspects of the present invention will become apparent from and elucidated with reference to the embodiments described hereinafter.

The invention will now be described, by way of example only, with reference to the accompanying drawing, in which:

Fig. 1 shows a schematic drawing of different components of a typical airplane engine of an exemplary embodiment of the invention.

Fig. 2 shows a schematic drawing of a pylon with engine including a nacelle and the wing of an airplane.

Fig. 3 shows a schematic drawing of the method according to the present invention (lower part) in comparison to the known method (upper part).

The illustration in the drawings is schematic. In different drawings similar or identical drawings elements are provided with the same reference numerals.

In Fig. 1 the different components of a typically engine of an airplane are schematically depicted. The air-inlet (101) is positioned in the front part of the engine. The reverser (102) and the nozzle (103) are in the back part of the engine.

The engine (104) itself is positioned in the middle and surrounded by a cowling (105).

Fig. 2 exhibits a schematic drawing of the installation of the pre-assembled pylon with engine unit (200) assembled and tested according to the method of the present invention to the wing (203). The pylon with engine unit (200) comprises the pylon (201), which connects the engine-unit (202) with the wing (203) of the airplane. The exemplary embodiment of the pylon with engine (200) does also exhibit a nacelle (204).

Fig. 3 illustrates the benefits of the method of the present invention (300) in comparison to the known process (301). The prior art process is depicted in the upper part of Fig. 3 and schematically shows the different assembly steps of an airplane. Exemplary units are depicted which may be pre-assembled in the separate assembling unit (302). While in the method known in the art, e.g. the pylon (303) and the electrical wiring (304) have to be installed to the wing of the airplane before testing (305). Within the method known in the art, after successful testing of the pylon (303) and the electrical wiring (304), the engine (306), the cowling (307) and the reverser (308) are subsequently installed to the pylon (303), which is already installed to the wing of the airplane. After the installation of the engine (306), the reverser (308), and the cowling (307)has been completed, the next testing (309) is performed. According to the method of the present invention, the engine (306), the cowling (307), and the reverser (308) are also pre-assembled in the separate pre- assembling unit (302) and after pre-assembling to the pylon (303) has been completed, tested. Thus, in the method according to the present invention, all these components (303, 304, 306, 307 and 308) are pre-assembled and optionally tested in the separate pre-assembling unit (302) as the pylon with engine

(310). Within the prior art process various test phases (305, 309, 311) e.g. for the pylon (303), the electrical wiring (304), the engine (306), engine cowling (307) or the reverser (308) had to be performed after installation to the wing. According to the method of the present invention, the pre-assembled pylon with engine unit (310) is assembled and optionally tested prior to installation to the wing. Thus, the method according to the present invention allows for parallel and earlier testing of the pre- assembled pylon with engine unit and therefore allows for shorter lead times, which is indicated by the time difference achieved by the method according to the present invention.

It is apparent for person skilled in the art, that the benefits of the present invention are not limited to the production of an airplane, but may also include benefits in the repair and maintenance time of every airplane.

It should be noted that the term "comprising" does not exclude other elements or steps and the "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined.

It should be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.