Patent Publication Number: US-10309726-B2

Title: Hinged baffle for autoclave that deploys at a target temperature during a run cycle

Description:
FIELD 
     This disclosure relates to the field of manufacturing, and more particularly, to autoclaves and associated manufacturing process that use autoclaves. 
     BACKGROUND 
     An autoclave is a device used in manufacturing of components, such as components made from composite materials. An autoclave includes a vessel where the pressure and temperature is controllable. Workpieces are placed inside the vessel, and the vessel is sealed. The vessel is then pressurized by pumping air or other gases through the vessel. The air enters the vessel through air inlets, and exits the vessel through air outlets. The temperature inside of the vessel may be controlled by the heating or cooling the air that is pumped through the vessel. The high-temperature and high-pressure capabilities of an autoclave make it useful for manufacturing processes, such as curing composite materials. 
     Although the pressure inside of the vessel is substantially uniform, the temperature of the workpiece being cured in the autoclave may not be uniform across its extent. This can be problematic when curing composite members, as some portions of a composite member may reach and maintain a proper cure temperature, while other portions may not. If portions of a composite member heat at different rates, the quality of the composite member may be compromised. 
     SUMMARY 
     Embodiments herein describe a baffle that is deployable during a run cycle of an autoclave. One or more of the baffles are installed in the interior of the autoclave in a non-deployed or retracted position. During a run cycle, the baffle automatically deploys when a temperature within the autoclave reaches a target temperature. In a deployed position, the baffle alters the airflow through the autoclave, and consequently changes the heat transfer coefficient at the surface of a workpiece in the autoclave. Therefore, the local heat transfer coefficients within the autoclave can be changed at different locations during a run cycle by deploying the baffle(s). 
     One embodiment comprises an apparatus that includes a baffle located in an autoclave during a run cycle of the autoclave. The apparatus also includes a release mechanism that secures the baffle in a retracted position during the run cycle, and automatically releases the baffle to a deployed position during the run cycle when a temperature inside of the autoclave reaches a target temperature. In the deployed position, the baffle alters airflow within the autoclave. 
     In another embodiment, the baffle attaches to a location inside of the autoclave with a hinge mechanism, where the baffle is configured to pivot via the hinge mechanism from the retracted position to the deployed position. 
     In another embodiment, the release mechanism includes a material that melts at the target temperature to release the baffle to the deployed position. 
     In another embodiment, the release mechanism includes a material that softens at the target temperature, and flexes to release the baffle to the deployed position. 
     In another embodiment, the release mechanism includes a Shape-Memory Alloy (SMA) material that has a first shape to secure the baffle in the retracted position, and transforms to a second shape at the target temperature to release the baffle to the deployed position. 
     In another embodiment, the apparatus includes a spring mechanism that loads when the baffle is secured in the retracted position, and applies a return force to pivot the baffle to the deployed position when released by the release mechanism. 
     In another embodiment, the apparatus includes a stop device that stops rotation of the baffle at the deployed position. 
     In another embodiment, the apparatus includes an indicator mechanism that indicates when the baffle is released to the deployed position. 
     In another embodiment, the indicator mechanism includes a thermocouple wire installed in a path between the retracted position and the deployed position of the baffle. The baffle breaks a connection of the thermocouple wire when pivoting from the retracted position to the deployed position. 
     Another embodiment comprises an autoclave and one or more baffle elements installed within the autoclave. The baffle element includes a baffle, a hinge mechanism that attaches the baffle to a surface inside of the autoclave, and a release mechanism that secures the baffle in a retracted position during a run cycle of the autoclave. The release mechanism automatically releases the baffle to a deployed position during the run cycle when a temperature inside of the autoclave reaches a target temperature. 
     Another embodiment comprises a method of operating an autoclave. The method includes performing a thermal-analysis of an interior of the autoclave, selecting a location for a baffle element within the autoclave based on the thermal-analysis, and installing the baffle element at the location. The method includes selecting a target temperature for deploying a baffle of the baffle element during a run cycle of the autoclave, and securing the baffle in the retracted position with a release mechanism. The method further includes initiating the run cycle, and releasing the baffle to the deployed position with the release mechanism during the run cycle when a temperature inside of the autoclave reaches the target temperature. 
     In another embodiment, the method includes selecting the release mechanism that changes state at the target temperature. 
     In another embodiment, the method includes selecting a material for the release mechanism that melts at the target temperature to release the baffle to the deployed position. 
     In another embodiment, the method includes selecting a material for the release mechanism that softens at the target temperature, and flexes to release the baffle to the deployed position. 
     In another embodiment, the method includes selecting a Shape-Memory Alloy (SMA) material for the release mechanism that transforms shapes at the target temperature to release the baffle to the deployed position. 
     In another embodiment, the method includes installing an indicator mechanism that indicates when the baffle is released to the deployed position. 
     In another embodiment, the method includes installing a thermocouple wire in a path between the retracted position and the deployed position of the baffle, where the baffle breaks a connection of the thermocouple wire when pivoting from the retracted position to the deployed position. 
     Another embodiment comprises a method of controlling heat within an autoclave. The method includes initiating a run cycle of the autoclave, and deploying a device within the autoclave during the run cycle to alter the airflow within the autoclave and change the heat transfer to one or more regions of the workpiece. 
     The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Some embodiments of the present invention are now described, by way of example only, with reference to the accompanying drawings. The same reference number represents the same element or the same type of element on all drawings. 
         FIG. 1  illustrates an autoclave in an exemplary embodiment. 
         FIG. 2  illustrates a baffle element in an exemplary embodiment. 
         FIG. 3  illustrates a baffle in a retracted position in an exemplary embodiment. 
         FIG. 4  illustrates a baffle in the deployed position in an exemplary embodiment. 
         FIG. 5  illustrates a spring mechanism for assisting the deployment of the baffle in an exemplary embodiment. 
         FIG. 6  illustrates a stop mechanism in an exemplary embodiment. 
         FIGS. 7-8  illustrate an indicator mechanism in an exemplary embodiment. 
         FIG. 9  is a flow chart illustrating a method of operating an autoclave in an exemplary embodiment. 
         FIG. 10  is a flow chart illustrating a method of controlling heat in an autoclave in an exemplary embodiment. 
         FIG. 11  is a flow chart illustrating an aircraft manufacturing and service method in an exemplary embodiment. 
         FIG. 12  is a schematic diagram of an aircraft in an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The figures and the following description illustrate specific exemplary embodiments. It will be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles described herein and are included within the contemplated scope of the claims that follow this description. Furthermore, any examples described herein are intended to aid in understanding the principles of the disclosure, and are to be construed as being without limitation. As a result, this disclosure is not limited to the specific embodiments or examples described below, but by the claims and their equivalents. 
       FIG. 1  illustrates an autoclave  100  in an exemplary embodiment. Autoclave  100  includes a cylindrical vessel  102  having an interior  104  in which workpieces are placed during a run cycle. Vessel  102  has a door  106  located at one end, and a wall  108  or enclosure located on the opposing end. Door  106  includes a plurality of air inlets  110 , and wall  108  includes one or more air outlets  112 . Air is introduced into vessel  102  through air inlets  110 , circulates through the interior  104  of vessel  102 , and exits out of air outlets  112 . Autoclave  100  may include one or more fans that blow air into air inlets  110 , and may include a heater for heating the air that is circulated through vessel  102 . Vessel  102  also includes a platform  116  or catwalk to allow operators to walk into autoclave  100  to load or remove workpieces, perform maintenance, etc. Substructures may be placed on platform  116 , and the workpieces may be loaded onto the substructures for a run cycle. The structure of autoclave  100  is just an example, and the embodiments described below may apply to different types of autoclaves. 
     For a typical run cycle of autoclave  100 , one or more workpieces are loaded into vessel  102 , and door  106  is sealed. Pressure is applied to vessel  102  by introducing air into air inlets  110 , while the temperature in vessel  102  is ramped up to a hold temperature. The temperature within vessel  102  may be held at this temperature for a length of time to complete a process, such as a cure process. Although the pressure inside vessel  102  is uniform, the air speed may vary inside vessel  102 . As hot air flows through vessel  102  from air inlets  110  to air outlets  112 , the airflow may not have a consistent pattern throughout the volume of vessel  102 . The uneven airflow leads to temperature variations across workpieces within vessel  102 . The temperature variations may depend on the design of vessel  102 , the shape of the workpiece(s), placement of the workpiece(s) within vessel  102 , the shape of substructures within vessel  102 , etc. 
     The following embodiments are able to compensate for the temperature variations within autoclave  100  and other types of autoclaves using one or more deployable baffle elements  150  that automatically deploy during a run cycle. As shown in  FIG. 1 , one or more baffle elements  150  are installed in the interior  104  of autoclave  100 . Baffle element  150  comprises any device or component within autoclave  100  that is deployable during a run cycle to change airflow within autoclave  100 . As will be further described below, baffle element  150  is initially set in a retracted position where it causes little or no turbulence in the airflow within autoclave  100 . During a run cycle of autoclave  100 , baffle element  150  automatically deploys at a certain temperature to a position where it causes turbulence in the airflow. The turbulence caused by baffle element  150  changes the airflow pattern within autoclave  100 . Increasing the speed of the air flowing across a workpiece improves heat transfer to that workpiece, while decreasing the speed of air flowing across a workpiece decreases heat transfer to that workpiece. Therefore, locations on workpieces within autoclave  100  that are heating quickly or slowly can be changed during a run cycle to improve curing processes or the like. 
       FIG. 2  illustrates baffle element  150  in an exemplary embodiment. Baffle element  150  is configured to be installed in interior  104  of autoclave  100 , and change the airflow within autoclave  100  during a run cycle. Baffle element  150  includes a baffle  201  attached to a hinge mechanism  202 . Baffle  201  is a device that restrains the flow of air. The shape and size of baffle  201  as shown in  FIG. 2  is just one example, and may vary as desired. Baffle  201  attaches to a surface within autoclave  100  via hinge mechanism  202 . Hinge mechanism  202  comprises any structure that pivots at a joint. In this embodiment, hinge mechanism  202  includes a first component  210  for attaching to a surface within autoclave  100 , a second component  211  for attaching to baffle  201 , and a pivoting joint  214  that connects components  210 - 211 . The structure of hinge mechanism  202  as shown in  FIG. 2  is just one example, and may vary as desired. 
     Baffle  201  is configured to transition from a retracted position to a deployed position at a certain temperature. Therefore, baffle element  150  further includes a release mechanism that is configured to hold baffle  201  in the retracted position, and to release baffle  201  to the deployed position during a run cycle at a certain temperature or temperature range, which is referred to as the “target” temperature.  FIG. 3  illustrates baffle  201  in a retracted position in an exemplary embodiment.  FIG. 3  is a side view of baffle element  150  installed on a surface  302  within autoclave  100 . Surface  302  represents any surface within vessel  102  of autoclave  100 . Surface  302  may represent the ceiling of autoclave  100 , a side wall of autoclave  100 , a platform or floor of autoclave  100 , a substructure within autoclave  100 , etc. Hinge  202  attaches baffle  201  to surface  302 , and baffle  201  is pivoted or rotated into the retracted position toward surface  302 . The retracted position is where the major surface of baffle  201  is in-plane or substantially in-plane with the airflow  330  within autoclave  100  to cause minimal deflection of the airflow  330 . Baffle  201  is secured in the retracted position by a release mechanism  310 . Release mechanism  310  is configured to hold baffle  201  in the retracted position below the target temperature, and release baffle  201  at or above the target temperature. For example, release mechanism  310  may include a latch device  312  that attaches to surface  302  (or another surface that is fixed in relation to baffle  201 ), and contacts baffle  201  (or hinge mechanism  202 ) to secure baffle  201  in the retracted position. 
     In order to release baffle  201  at the target temperature, latch device  312  may include a material that melts or softens at the target temperature, such as a metal alloy that includes lead or tin, a thermoplastic, etc. When an operator of autoclave  100  determines the target temperature for baffle  201  to deploy, the operator may also select the type of material for latch device  312  that melts or softens at that target temperature. Latch device  312  will therefore secure baffle  201  in the retracted position as the temperature rises within autoclave  100  during a run cycle. When the temperature reaches the target temperature, latch device  312  will melt to release baffle  201 , or will soften and flex to release baffle  201 . 
     Latch device  312  may alternatively include a Shape-Memory Alloy (SMA) that transforms shapes at the target temperature, or a bimetal that flexes at the target temperature. SMAs are strong-lightweight alloys that can be programmed to remember different shapes at different temperatures. Examples of SMA materials include Nickel-Titanium (Ni—Ti), Nickel-Titanium-Hafnium (Ni—Ti—Hf), Copper-Aluminum-Nickel (Cu—Al—Ni), etc. SMAs display two distinct crystal structures or phases. Martensite form exists at lower temperatures, and austenite form exists at higher temperatures. When an SMA is in martensite form at lower temperatures, it can be easily formed to a desired shape. When the SMA is in austenite form at higher temperatures, it can be “trained” to transition into another shape. For example, the SMA may be bent, squeezed, twisted, or otherwise formed to have a different shape when in the austenite form. When made from SMA material, latch device  312  will therefore secure baffle  201  in the retracted position when the SMA material is in its low-temperature (martensite) shape. When the temperature reaches the target temperature, the SMA material in latch device  312  will transition from its low-temperature (martensite) shape to its high-temperature (austenite) shape and release baffle  201 . 
     Release mechanism  310  may have other desired structures not shown so that latch device  312  releases baffle  201  at the target temperature. For example, latch device  312  may be coupled to an actuator. A controller may measure a temperature within autoclave  100  through a temperature sensor, and reposition latch device  312  through the actuator when the temperature reaches the target temperature in order to release baffle  201 . 
       FIG. 4  illustrates baffle  201  in the deployed position in an exemplary embodiment.  FIG. 4  is again a side view of baffle element  150  installed in autoclave  100 . To transition to the deployed position, baffle  201  is pivoted or rotated away from surface  302  via hinge mechanism  202 . The deployed position is where the major surface of baffle  201  is out-of-plane with the airflow  330  within autoclave  100  to cause deflection of the airflow  330 . As illustrated in  FIG. 4 , baffle  201  pivots on hinge mechanism  202  from the retracted position to the deployed position. When in the deployed position, baffle  201  will perturb or alter the airflow  330  within autoclave  100  which in turn alters the temperature distribution within autoclave  100 . 
     Baffle  201  may pivot from the retracted position to the deployed position due to gravity. The weight of baffle  201  may be selected so that it overcomes the force of airflow  330 , and baffle  201  is able to pivot to and remain in the deployed position. Deployment of baffle  201  may also be assisted with a spring mechanism or the like.  FIG. 5  illustrates a spring mechanism  502  for assisting the deployment of baffle  201  in an exemplary embodiment. In this embodiment, spring mechanism  502  is installed between components  210  and  211  of hinge mechanism  202 . Spring mechanism  502  loads when baffle  201  is pivoted into the retracted position, and applies a return force to pivot baffle  201  to the deployed position. The return force applied by spring mechanism  502  assists in overcoming the force of airflow  330  so that baffle  201  can fully reach the deployed position and stay in the deployed position. The structure of spring mechanism  502  as shown in  FIG. 5  is just one example, and may vary as desired. 
     In order to stop baffle  201  at the deployed position, baffle element  150  may include a stop mechanism that is used in conjunction with hinge mechanism  202 . The stop mechanism may comprise any structure or device that stops the rotation of baffle  201  via hinge mechanism  202  at the deployed position.  FIG. 6  illustrates a stop mechanism  602  in an exemplary embodiment. Stop mechanism  602  includes one end  604  that attaches to surface  302  (or another surface that is fixed in relation to baffle  201 ), and another end  606  that is in the path of rotation of baffle  201 . When baffle  201  pivots on hinge mechanism  202  and strikes end  606 , baffle  201  stops in the desired position. The structure of stop mechanism  602  as shown in  FIG. 6  is just an example, and may vary as desired. For example, a spring-loaded pin may be used to act as a stop mechanism for stopping baffle  201  at the deployed position. In another example, a cable may be attached between surface  302  and baffle  201 , which stops baffle  201  after pivoting to the deployed position. 
     An operator may not be able to see inside autoclave  100  during a run cycle to determine if or when baffle  201  deploys. Therefore, it may be advantageous to install a device in autoclave  100  that indicates when baffle  201  deploys.  FIGS. 7-8  illustrate an indicator mechanism  702  in an exemplary embodiment. Indicator mechanism  702  comprises any device that indicates when baffle  201  is deployed into the deployed position. In the embodiment shown in  FIG. 7 , indicator mechanism  702  may include a thermocouple wire  704  that is strung across the path of baffle  201  between the retracted position and the deployed position. Thermocouple wire  704  may be used to connect a temperature sensor  706  inside of autoclave  100  to instrumentation  708  outside of autoclave  100 . Temperature sensor  706  is configured to read an air temperature within autoclave  100 . Because thermocouple wire  704  is strung across the path of baffle  704 , baffle  704  will break the connection made by thermocouple wire  704  between temperature sensor  706  and instrumentation  708  when it rotates from the retracted position to the deployed position (see  FIG. 8 ). For instance, assume that temperature sensor  706  reads temperatures increasing from 70° F. to 180° F., which are displayed to an operator by instrumentation  708 . When baffle  201  is released at the target temperature and pivots towards the deployed position, baffle  201  breaks the connection between temperature sensor  706  and instrumentation  708 . Therefore, instrumentation  708  will show a rapid decrease in temperature because the connection with temperature sensor  706  is lost. This indicates to the operator that baffle  201  has been deployed. 
     The structure of indicator mechanism  702  as shown in  FIGS. 7-8  is just an example, and may vary as desired. For example, a laser sensor may be installed in autoclave  100  to detect when baffle  201  deploys, a switch may be installed in autoclave  100  that is pressed or contacted by baffle  201  when deployed, etc. 
     Multiple baffle elements  150  as described above may be installed within autoclave  100 . The number and locations of the baffle elements  150  may depend on the temperature distribution within autoclave  100 , and the airflow changes desired during a run cycle. The size and shape of each baffle element  150  may differ depending on the airflow changes desired in autoclave  100 . Also, different baffle elements  150  may be utilized that deploy at different temperatures. For example, an operator of autoclave  100  may want one baffle element  150  to deploy at target temperature t1, another baffle element  150  to deploy at target temperature t2, and another baffle element  150  to deploy at target temperature t3, which are different temperatures. To do so, the release mechanism  310  for each baffle element  150  is configured to deploy at the different target temperatures. 
     An operator of autoclave  100  may use baffle element  150  in manufacturing processes, such as for curing composite materials.  FIG. 9  is a flow chart illustrating a method  900  of operating autoclave  100  in an exemplary embodiment. The steps of the methods described herein are not all inclusive and may include other steps not shown. The steps for the flow charts shown herein may also be performed in an alternative order. 
     Method  900  includes performing a thermal-analysis of autoclave  100  (step  902 ), and more particularly, a thermal-analysis of interior  104  of autoclave  100 . For instance, a modeling program may be used to model the volume of autoclave  100 , airflow patterns within autoclave  100 , temperature variations within autoclave  100 , etc. The modeling program may also be used to model the airflow with one or more workpieces loaded within autoclave  100 . Because more airflow across a workpiece improves heat transfer to the workpiece, and less airflow across the workpiece decreases heat transfer to the workpiece, heat transfer from the airflow to regions of the workpiece may be identified or modeled. Different heat transfer characteristics may be more evident on larger workpieces. 
     Method  900  may further include selecting a location for a baffle element  150  within autoclave  100  based on the thermal-analysis (step  904 ). The location for baffle element  150  may be selected for altering the airflow  330  during a run cycle of autoclave  100  to change the heat transfer on one or more regions of the workpiece. For example, if the thermal-analysis indicates a faster airflow along one region of the workpiece and a slower airflow along another region, the location of baffle element  150  may be selected to change the airflow pattern with autoclave  100  so that these different regions of the workpiece are heated to similar temperatures. Baffle element  150  may be situated to deflect air from a faster-airflow area within autoclave  100  to slower-airflow areas within autoclave  100 . Baffle element  150  is then installed at the selected location (step  906 ). The modeling program may also be used to select the location for baffle element  150 , and to determine how baffle element  150  affects the airflow pattern within autoclave  100 . 
     Method  900  further includes selecting a target temperature for deploying the baffle element  150  during a run cycle of autoclave  100  (step  908 ). Method  900  may further include selecting a release mechanism  310  that changes state at the target temperature (step  910 ). Step  910  is an optional step depending on the type of release mechanism  310  that is used. For example, the operator may select a material for release mechanism  310  that melts at the target temperature, changes shape (e.g., SMA) at the target temperature, or otherwise changes state at the target temperature. Method  900  further includes securing the baffle  201  of the baffle unit  150  in the retracted position with the release mechanism (step  912 ). 
     Steps  904 - 912  may be performed multiple times for multiple baffle elements  150  as desired. 
     With the baffle element(s)  150  installed within autoclave  100  at the desired location(s) and set in the retracted position, a run cycle for autoclave  100  may be initiated (step  914 ). It is assumed that workpieces are also loaded into autoclave  100  for the run cycle. The run cycle includes pressurizing autoclave  100 , and ramping up the temperature within autoclave  100  to a hold temperature. When the temperature of airflow  330  proximate to or surrounding the release mechanism  310  of baffle element  150  reaches the target temperature, the baffle  201  is released and pivots from the retracted position to the deployed position (step  916 ). The deployment of baffle  201  changes the airflow within autoclave  100 . This changes the heat transfer coefficient at various locations around workpieces within autoclave  100 . By being able to change the heat transfer coefficient during a run cycle of autoclave  100 , all regions of a workpiece (especially a large workpiece) are subjected to similar temperatures during the run cycle. For example, if the workpieces are composites that are being cured, all regions of the composite will be cured according to the desired cure specifications. 
     Deployment of a baffle element  150  during a run cycle of autoclave  100  enables control over heat within autoclave  100  on different regions of a workpiece.  FIG. 10  is a flow chart illustrating a method  1000  of controlling heat in autoclave  100  in an exemplary embodiment. For method  1000 , heat transfer from airflow  330  to regions of a workpiece within autoclave  100  are modeled (step  1002 ). Heat transfer refers to the exchange of thermal energy between airflow  330  and the workpiece within autoclave  100 . The heat transfer can be modeled based on the airflow patterns within autoclave  100 . The modeling may indicate the regions on the workpiece with higher heat transfer, and indicate regions on the workpiece with lower heat transfer. Method  1000  may further include selecting a location for a device (e.g., baffle element  150 ) within autoclave  100  for altering the airflow  330  (step  1004 ). The location for the device may be selected for altering the airflow  330  during a run cycle of autoclave  100 . The device may then be installed at the selected location (step  1006 ) within autoclave  100 , such as on the ceiling, wall, or floor of autoclave  100 , on a substructure within the autoclave  100 , etc. Method  1000  further includes initiating a run cycle of autoclave  100  (step  1008 ). During the run cycle, the device (e.g., baffle element  150 ) is deployed within autoclave  100  to alter the airflow  330  within autoclave  100  and change the heat transfer to one or more of the regions of the workpiece (step  1010 ). As above, the device may be deployed when the temperature of airflow  330  reaches a target temperature. 
     The embodiments of the disclosure may be described in the context of an aircraft manufacturing and service method  1100  as shown in  FIG. 11  and an aircraft  1100  as shown in  FIG. 12 . During pre-production, exemplary method  1100  may include specification and design  1104  of aircraft  1200 , and material procurement  1106 . During production, component and subassembly manufacturing  1108  and system integration  1110  of aircraft  1200  takes place. Thereafter, aircraft  1200  may go through certification and delivery  1112  in order to be placed in service  1114 . While in service by a customer, aircraft  1200  is scheduled for routine maintenance and service  1116  (which may also include modification, reconfiguration, refurbishment, and so on). 
     Each of the processes of method  1100  may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of venders, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on. 
     As shown in  FIG. 12 , aircraft  1200  produced by exemplary method  1100  may include an airframe  1202  with a plurality of systems  1204  and an interior  1206 . Examples of high-level systems  1204  include one or more of a propulsion system  1208 , an electrical system  1210 , a hydraulic system  1212 , and an environmental system  1214 . Any number of other systems may be included. Although an aerospace example is shown, the principles described in this specification may be applied to other industries, such as the automotive industry. 
     Apparatus and methods embodied herein may be employed during any one or more of the stages of the production and service method  1100 . For example, components or subassemblies corresponding to production process  1108  may be fabricated or manufactured in a manner similar to components or subassemblies produced while aircraft  1200  is in service. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during the production stages  1108  and  1110 , for example, by substantially expediting assembly of or reducing the cost of aircraft  1200 . Similarly, one or more of apparatus embodiments, method embodiments, or a combination thereof may be utilized while aircraft  1200  is in service, for example and without limitation, to maintenance and service  1116 . 
     Any of the various elements shown in the figures or described herein may be implemented as hardware, software, firmware, or some combination of these. For example, an element may be implemented as dedicated hardware. Dedicated hardware elements may be referred to as “processors”, “controllers”, or some similar terminology. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. Moreover, explicit use of the term “processor” or “controller” should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, a network processor, application specific integrated circuit (ASIC) or other circuitry, field programmable gate array (FPGA), read only memory (ROM) for storing software, random access memory (RAM), non-volatile storage, logic, or some other physical hardware component or module. 
     Also, an element may be implemented as instructions executable by a processor or a computer to perform the functions of the element. Some examples of instructions are software, program code, and firmware. The instructions are operational when executed by the processor to direct the processor to perform the functions of the element. The instructions may be stored on storage devices that are readable by the processor. Some examples of the storage devices are digital or solid-state memories, magnetic storage media such as a magnetic disks and magnetic tapes, hard drives, or optically readable digital data storage media. 
     Although specific embodiments were described herein, the scope is not limited to those specific embodiments. Rather, the scope is defined by the following claims and any equivalents thereof.