Abstract:
Apparatus and method for removing an aircraft engine. A method includes mounting a frame assembly in supported connection with a support member of an associated aircraft. The frame assembly includes a frame member, a movable assembly mounted in movable relationship to the frame member, and a plurality of engine winches mounted in supported connection with the movable member. Each engine winch has an associated engine cable operably connected thereto. The movable assembly is movable between forward and rearward positions. The method further includes supporting the weight of at least a portion of an aircraft engine with the engine cables and moving the movable member relative to the frame member to displace the portion of the aircraft engine.

Description:
This invention relates generally to aircraft engine assemblies, and more specifically to methods and apparatuses for mounting and dismounting aircraft engines. 
     Large turbofan gas turbine engines may be considered ready for installation on an associated aircraft when the fan module and inlet are assembled to the remaining engine components. During engine service, the fan module and inlet may remain attached to the engine components, although the turbofan overhaul practices typically involve refurbishment of the core module of the engine with limited need for fan module work. Thus, removal of the fan module during the engine overhaul process leads to wasted shop floor space. Additionally, shipment of the engine may require removal of the inlet and often the fan module due to cargo aircraft door opening restrictions and roadway obstructions. 
     Accordingly, it would be desirable to provide engine structures and mounting/dismounting methods that reduce the shop floor space required for engine overhaul and facilitate shipment of engine components. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Exemplary embodiments disclosed herein provide methods and apparatuses for mounting and dismounting gas turbine engines from associated aircraft. 
     In one exemplary embodiment, an apparatus includes a frame assembly configured for mounting to support structure of an associated aircraft. The frame assembly comprises a frame member, a movable assembly mounted in movable relationship to the frame member, wherein the movable assembly is movable between forward and rearward positions, and a plurality of engine winches mounted in supported connection with the movable member. Each engine winch has an associated engine cable operably connected thereto. The frame assembly is operable to movably support at least a portion of an associated aircraft engine. 
     In an exemplary embodiment, a method includes mounting a frame assembly in supported connection with a support member of an associated aircraft. The frame assembly includes a frame member, a movable assembly mounted in movable relationship to the frame member, wherein the movable assembly is movable between forward and rearward positions, and a plurality of engine winches mounted in supported connection with the movable member. Each engine winch has an associated engine cable operably connected thereto. The method also includes supporting the weight of at least a portion of an aircraft engine with the engine cables, and moving the movable member relative to the frame member to displace the portion of the aircraft engine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding part of the specification. The invention, however, may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which: 
         FIG. 1  is a side view, partly in section, of an exemplary embodiment of an assembly showing a monolithic structure and a gas turbine engine assembly. 
         FIG. 2  is a side view, partly in section, of an exemplary monolithic structure and gas turbine illustrating partial disassembly and removal of a gas turbine engine. 
         FIG. 3  is a perspective view, partly in section, illustrating the positioning of a frame assembly utilized to facilitate dismounting a gas turbine engine assembly from an associated aircraft. 
         FIG. 4  is a perspective view of an exemplary frame assembly. 
         FIG. 5  is an aft-looking-forward perspective view of an exemplary frame assembly arrangement for facilitating dismounting a gas turbine engine assembly from an associated aircraft. 
         FIG. 6  is a side view, partly in section, illustrating rearward displacement of a gas turbine engine assembly while supported on a frame assembly. 
         FIG. 7  is a side view, partly in section, illustrating attachment and alignment of a cart or trolley used to facilitate dismounting a gas turbine engine assembly from an associated aircraft. 
         FIG. 8  is an aft-looking-forward perspective view illustrating a raised cart or trolley. 
         FIG. 9  is a side view, partly in section, showing a dismounted gas turbine engine assembly supported on a cart or trolley. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Exemplary embodiments disclosed herein are directed to methods and apparatuses for removing or installing a gas turbine engine. In general terms, the gas turbine engine is adapted for supported connection with a monolithic structure that is semi-permanently attached to an associated aircraft. An exemplary monolithic structure is shown and described in copending patent application Ser. No. 12/343,833, filed Dec. 24, 2008, the entirety of which is incorporated herein by reference. It is envisioned that the methods and apparatuses described herein may be readily adapted for use with other engine-to-aircraft supporting structures by those having skill in the relevant art. 
     With reference to  FIG. 1 , there is provided an assembly  10  including an exemplary monolithic structure  12  and a gas turbine engine assembly  70 . The exemplary monolithic structure  12  includes a nacelle portion  14  arranged and dimensioned for encircling at least a portion of a gas turbine engine assembly, notably the fan assembly  38 . The exemplary nacelle portion  14  is integral with an axially extending support structure portion  16 . The exemplary support structure portion  16  is arranged and dimensioned for supporting the weight of the engine, and for reacting and transmitting static and dynamic loads to the associated aircraft. In an exemplary embodiment, a portion of an installed gas turbine engine extends through a ring member  30  disposed in the nacelle portion  14  of the monolithic structure  12 . 
     In an exemplary embodiment, the gas turbine engine assembly  70  is disengaged or dismounted from an associated aircraft  13  while the exemplary monolithic structure  12  remain mounted thereto. With reference to  FIGS. 2-9 , in general terms, a frame assembly  40  is utilized to facilitate the removal of an installed gas turbine engine. The exemplary frame assembly  40  attaches to a support member  34  which may comprise the support structure portion  16  of the exemplary monolithic structure  12 . Those having skill in the art will appreciate that the exemplary frame assembly  40  may be utilized in conjunction with a conventional pylon or support strut. Following removal of at least a portion of the fan assembly  38 , the weight of the remainder of the engine is transferred from the support member  34  to the frame assembly  40  via forward and rear engine cables  55 ,  57 , respectively. The exemplary frame assembly  40  facilitates rearward movement of the remainder of the gas turbine engine, herein referred to as the core engine  41 . When the engine has been sufficiently displaced, a cart or trolley  80  is raised to meet the core engine  41 . In an exemplary embodiment, the entire cart or trolley is raised off the ground as illustrated in the accompanying figures. Those with skill in the art will appreciate that an alternative cart or trolley may instead be fitted with a vertically displaceable cradle or other structure that may be raised toward the engine while a body of the cart or trolley remains on the ground. In an exemplary embodiment, the weight of the engine is transferred to the cart or trolley  80  and the trolley/engine assembly  90  is then lowered to the ground. In an exemplary embodiment, the monolithic structure  12  remains installed on the associated aircraft. The core engine  41  is thus ready for service or shipment. In an exemplary embodiment, the trolley/engine assembly  90  is sufficiently sized and dimensioned to fit within a standard shipping container. Because the inlet/fan case assembly does not remain attached to the engine as in prior engine service removals, less shop floor space is required. The proceeding description provides a general background of the invention disclosed herein. Exemplary embodiments are described with greater specificity below. 
     With particular reference to  FIG. 2 , in an exemplary embodiment, a fan assembly  38  may be disassembled from a core engine  41 . For ease of illustration, certain elements of the fan assembly are shown in an exploded view; however, complete disassembly of the fan assembly members is not required for purposes of the invention. The fan assembly  38  is removed from the core engine through a forward or inlet region  22  of the monolithic structure  12 , as indicated by Arrow  24 . In an exemplary embodiment, a booster outer case  25  may also be removed. When present, all or a portion of a thrust reverser assembly or other aero structures may be moved or removed to permit access to the core engine. In certain exemplary embodiments, all or a portion of the core case may be removed. For ease of illustration, the core case is not shown in the accompanying drawings. 
     With reference to  FIG. 3 , an engine removal frame assembly  40  is installed to facilitate removal of a core engine  41 . In an exemplary embodiment, the frame assembly  40  includes right- and left-side forward supports  42  which are selectively fixedly secured to opposing sides of a support member  34  (left side forward support shown, relative to an aft-looking-forward view). As used herein, “support member  34 ” refers to a structural element adapted to generally extend between a wing or other suitable appendage of an associated aircraft and the gas turbine engine assembly, and to which the gas turbine engine assembly is operationally mounted. In an exemplary embodiment, the term “support member  34 ” may comprise the support structure portion  16  of the monolithic structure  12  referenced above, but the embodiments disclosed herein are not so limited. With particular reference to  FIG. 4 , an exemplary engine removal frame assembly  40  includes a generally u-shaped frame member  44  capable of attachment to the right- and left-side forward supports  42  at the forward ends of side members  46 . For simplicity, the frame member is described as being “u-shaped” although other arrangements of parts and configurations are with the scope of the present invention. The exemplary frame assembly  40  includes a rear cross member  48  including a rear hanger  50  adapted for engagement with the support member  34  or some other suitable aircraft structure. In an exemplary embodiment, the rear hanger may be capable of sharing a connection site, such as an aft wing mount, where the support member  34  is mounted to the associated aircraft. 
     The frame member  44  may be an integral structure, or it may include separate, selectively joinable pieces. One or more pairs of optional right- and left-side mid supports  52 , adapted for engagement with the support member  34  between the forward supports  42  and the rear hanger  50 , may be carried on the frame member  44 . With reference to  FIG. 5 , the engine removal frame assembly  40  includes a pair of forward engine winches  54  and associated forward engine cables  55 , and a pair of rear engine winches  56  and associated rear engine cables  57 . In an exemplary embodiment, the frame assembly also includes a pair of forward cart winches  58  and associated forward cart cables  59  and rear cart winches  60  and associated rear cart cables  61  as discussed in greater detail below. In an exemplary embodiment, right- and left-side forward and rear trucks,  62 ,  63 , respectively, are joined with a connector bar  64  for coordinated movement along rails  66  of side members  46 . In an exemplary embodiment, a cradle or other support member  68  may be carried on the forward engine cables  55  and used to support at least a portion of the core engine  41  as provided in greater detail below. In other exemplary embodiments, other supporting members or means may be used. 
     In an exemplary embodiment, the cart or trolley  80  may include braces or other structures, such as front brace  82  and rear brace  84  adapted to receive and support the core engine  41  on cart or trolley  80 . In an exemplary embodiment, the cart or trolley  80  may include wheels. In an exemplary embodiment, the cart or trolley  80  is adapted to be supported by support member  34 , and ultimately by the associated aircraft  13 . The cart or trolley  80  may be designed so that its weight is readily supportable by the associated aircraft. 
     An exemplary method for removing a gas turbine engine from supported connection with a support member  34  and the associated aircraft  13  is provided. In an exemplary embodiment, if necessary, certain aero structures (cowls, fairings, thrust reversers) are moved or removed from the engine assembly. In an exemplary embodiment, the fan assembly  38  is at least partially disassembled. In an exemplary embodiment, the right and left-side forward supports  42  are selectively mounted to the support structure  34 . The frame member  40  is positioned so that the right- and left-side members engage the respective forward support  42 . The rear hanger  50  is connected to the aft wing mount, or other predetermined location in supported connection with the support structure  34 . The right- and left-side mid supports  52 , if present, are mounted in supported connection with the support structure  34 . The forward and rear engine cables  55 ,  57 , respectively and cradle  68 , if present, are arranged to accept the weight of the core engine  41 . 
     With particular reference to  FIGS. 6-9 , certain mounting assemblies are disengaged between the core engine  41  and the support structure  34  so that the weight of the core engine may be supported by engine cables  55 ,  57 . For example, those with skill in the art will appreciate that various attachments, bolts, and mounting fixtures may be disengaged to allow rearward movement of the remainder of the gas turbine engine. Also, those with skill in the art will understand that gages or other devices may be utilized to indicate the loads borne by the mounting assemblies and/or the engine cables. The core engine  41  is then rearwardly displaced by travel of trucks  62 ,  63  along rails  66 . Once the core engine is sufficiently displaced, the forward and rear cart winches  58 ,  60 , respectively, may be utilized to raise the cart or trolley  80  to meet the core engine. In an exemplary embodiment, the forward and rear cart cables  59 ,  61 , respectively, provide a self-alignment mechanism for the cart or trolley  80  as it is raised relative to the core engine  41 . After the cart or trolley  80  has been adequately positioned in relationship to the core engine, the forward and rear engine cables  55 ,  57 , respectively, may be released to transfer the weight of the core engine  41  to the cart or trolley  80  via the cart cables  59 ,  61 . The cart or trolley is then lowered to the floor. The cart cables may be disengaged from the cart. The trolley/engine assembly  90  is then ready for transport to a service bay, shipping container, and the like. 
     In an exemplary embodiment, the frame assembly  40  may remain mounted to the support member  34 . In an exemplary embodiment, the monolithic structure  12  remains mounted on the associated aircraft  13 . A replacement core engine may be installed, or the core engine  41  may be reinstalled after service. In general, an installation method reverses the aforementioned sequence. 
     In an alternate exemplary embodiment, the cart or trolley  80  may be raised via the cart cables and fixed to the engine prior to rearward displacement. The weight of the cart or trolley may be supported along with the engine by support member  34 . The core engine/trolley assembly may then be supported by appropriate means such as the cart cables, and displaced rearwardly as earlier described. The core engine/trolley assembly could then be lowered to the ground using the cart winches. In this alternate arrangement, separate engine cables and engine winches may be eliminated. 
     Thus, exemplary embodiments disclosed herein provide apparatuses and methods for mounting and dismounting a gas turbine engine assembly relative to a supporting structure while a monolithic structure, including a nacelle region, remains in supported connection with the associated aircraft. The core engine may thus be readily serviced or replaced using less shop floor space. Additionally, the core engine may be shipped in standard shipping containers using conventional shipping means. 
     This written description uses exemplary embodiments to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.