METHOD FOR DETERMINING DATA TO BE TRANSMITTED OFF-AIRCRAFT FOR PROCESSING OF AIRCRAFT WEIGHT AND CENTER OF GRAVITY INFORMATION
20220414681 · 2022-12-29
Inventors
Cpc classification
International classification
Abstract
An aircraft operation method of providing weight and center of gravity information is used to dispatch the aircraft. The aircraft has telescoping landing gear struts and strut seals that interfere with the free movement of the strut. An event trigger generated manually or automatically by an activation device triggers measurement and recording of internal strut pressure for a period of time. The recorded pressure measurements are transmitted to a first off-aircraft computer, which determines the total weight and center of gravity of the aircraft and provides the information to an operator of the aircraft.
Claims
1. An aircraft operation method of providing weight and center of gravity information for a flight of the aircraft, the aircraft having plural pressurized landing gear, the landing gear comprising telescoping landing gear struts that support weight of the aircraft while not in flight, the landing gear having strut seals for retaining pressure within the telescopic struts, the strut seals creating friction that interferes with free telescoping movement of the respective landing gear struts, which distort the direct relationship of measured pressure used to measure supported weight, the method comprising the steps of: a. providing an activation device, the activation device being structured and arranged to generate an event trigger upon activation; b. after generation of the event trigger by the activation device, measuring and recording internal pressure from the respective landing gear struts with an on-aircraft computer; c. continuing to measure and record internal pressure from the landing gear struts for a period of time; d. transmitting the recorded strut pressure measurements for the period of time to an off-aircraft computer; e. processing the transmitted recorded strut pressure measurements and correcting for the friction interference created by the strut seals, using the off-aircraft computer; f. determining a total weight of the aircraft and the aircraft center of gravity using the off-aircraft computer; g. providing the total weight of the aircraft and the aircraft center of gravity from the off-aircraft computer to an operator of the aircraft.
2. The aircraft operation method of claim 1, the activation device being positioned onboard the aircraft.
3. The aircraft operation method of claim 1 wherein the event trigger is generated by the activation device by automatic or manual activation of the activation device.
4. The aircraft operation method of claim 3 wherein the event trigger is manually generated by the activation device by movement of an activation mechanism.
5. The aircraft operation method of claim 3 wherein the activation mechanism is a button.
6. The aircraft operation method of claim 3 wherein the event trigger is automatically generated by the activation device upon entry of the aircraft into a preselected geo zone.
7. The aircraft operation method of claim 1 wherein the step of continuing to measure and record internal pressure from the landing gear struts for a period of time further comprises the step of ending the period of time upon the occurrence of a stop recording event.
8. The aircraft operation method of claim 7 wherein the step of continuing to measure and record internal pressure from the landing gear struts for a period of time further comprises the steps of detecting pressure oscillations in at least one of the landing gear struts and ending the period of time upon the end of a specific period of time, as the stop recording event.
9. The aircraft operation method of claim 8 wherein the step of transmitting the recorded strut pressure measurements for the period of time to the off-aircraft computer further comprises transmitting the recorded strut pressure measurements upon the occurrence of the stop recording event.
10. The aircraft operation method of claim 1 further comprising the step of using a library database to identify a respective landing gear with irregular friction patterns.
11. The aircraft operation method of claim 1, the off-aircraft computer being a first off-aircraft computer, wherein the step of providing the total weight of the aircraft and the aircraft center of gravity from the first off-aircraft computer to an operator of the aircraft, further comprises the step of transmitting the total weight of the aircraft and the aircraft center of gravity from the first off-aircraft computer to a second off-aircraft computer used by the operator of the aircraft.
12. An aircraft operation method of determining a weight of revenue payloads for a flight of the aircraft, the aircraft having plural pressurized telescoping landing gear struts that support weight of the aircraft while not in flight, the landing gear having strut seals for retaining pressure within the telescopic struts, the strut seals creating friction that interferes with a free telescoping movement of the landing gear struts, which distort the direct relationship of measured pressure used to measure supported weight, the method comprising the steps of: a. providing an activation device, the activation device being structured and arranged to generate an event trigger upon activation; b. after generation of the event trigger, measuring and recording internal pressure from the respective landing gear struts; c. continuing to measure and record internal pressure from the landing gear struts for a period of time; d. using the off-aircraft computer, correcting for the friction interference created by the strut seals and determining a total weight of the aircraft from the internal pressures; e. determining an operating empty weight of the aircraft; f. determining a weight of fuel onboard the aircraft; g. determining a weight of non-passenger cargo onboard the aircraft; h. determining a count of a number of passengers and passenger bags on the aircraft; i. using the total weight of the aircraft, the operating empty weight of the aircraft, the fuel weight, the non-passenger cargo weight, and the number of passengers and passenger bags, determining a per passenger weight and per passenger bag weight; j. recording the per passenger weight and per passenger bag weight for the flight.
13. The aircraft operation method of claim 12, wherein the event trigger is generated by the activation device by automatic or manual activation of the activation device.
14. The aircraft operation of method of claim 12, the event trigger signaling entry of the aircraft into a preselected geo zone.
15. The aircraft operation method of claim 12 further comprising the step of determining and compiling an average weight of a passenger on the flight, with carry-on items.
16. The aircraft operation method of claim 12 further comprising the step of determining and compiling an average weight of a checked bag on the flight.
17. The aircraft operation method of claim 12 further comprising the step of determining a weight of revenue payload associated with a particular set of destination city pairs.
18. The aircraft operation method of claim 15 further comprising the step of determining the weight of revenue payload associated with a particular time of day.
19. The aircraft operation method of claim 15 further comprising the step of determining the weight of revenue payload associated with a particular season of a year.
20. The aircraft operation method of claim 1, the activation device being positioned offboard the aircraft.
21. The aircraft operation method of claim 12, the activation device being positioned offboard the aircraft.
22. The aircraft operation method of claim 1, further comprising, after the step of continuing to measure and record internal pressure from the landing gear struts for a period of time, the step of determining whether the aircraft is not in motion.
23. The aircraft operation method of claim 22, wherein upon determining the aircraft is not in motion, the step of processing the transmitted recorded strut pressure measurements and correcting for the friction interference created by the strut seals, using the off-aircraft computer; further comprises applying predicted seal friction off-set values, historically compiled from each respective landing gear strut.
24. An aircraft operation method of providing weight and center of gravity information for a flight of the aircraft, the aircraft having plural pressurized landing gear, the landing gear comprising telescoping landing gear struts that support weight of the aircraft while not in flight, the landing gear having strut seals for retaining pressure within the telescopic struts, the strut seals creating friction that interferes with free telescoping movement of the respective landing gear struts, which distort the direct relationship of measured pressure used to measure supported weight, the method comprising the steps of: a. providing an activation device, the activation device being structured and arranged to generate an event trigger upon activation; b. after generation of the event trigger by the activation device, measuring and recording internal pressure from the respective landing gear struts with an on-aircraft computer; c. determining whether internal pressures from the respective landing gear struts have ceased changing; d. determining most recent increase or decrease from pressure change, from the respective landing gear struts; e. correcting respective pressures for the friction interferences, using friction predictive software algorithms; f. processing respective corrected strut pressures for the friction interferences created by the strut seals, using the on-aircraft computer; g. determining a total weight of the aircraft and the aircraft center of gravity using the on-aircraft computer; h. providing the total weight of the aircraft and the aircraft center of gravity from the on-aircraft computer to an operator of the aircraft.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0134] Although the features of this invention, which are considered to be novel, are expressed in the appended claims, further details as to preferred practices and as to the further objects and features thereof may be most readily comprehended through reference to the following description when taken in connection with the accompanying drawings, wherein:
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0150] The present invention provides methods for efficient identification and capture of preferred sequence of pressure oscillation patterns, by an on-aircraft computer, with further processing by a first off-aircraft computer to filter and remove pressure outliers and asymmetries identified in the high-peak and the low-peak pressure averages; to determine to a single pressure value which directly corresponds to the supported weight. The steps to reduce the amount of captured strut pressure and rotation sensor data, transmitted wirelessly from the on-aircraft computer include: [0151] 1. Measurement of respective landing gear strut pressure, over elapsed time [0152] 2. Optional measurement of corresponding landing gear torque-link rotation; [0153] 3. Capturing a portion (being the preferable patterns of strut pressure oscillation) of the respective landing gear strut pressure and, optionally, corresponding torque-link rotation measurements: [0154] a. prior to gate departure, [0155] b. during aircraft movement, such as by push-back, from the gate, [0156] c. during aircraft taxi-time prior to aircraft take-off; [0157] 4. Correlating all respective pressure and rotation measurements with a date and time stamp; [0158] 5. Identifying the appropriate segments of recorded pressure and rotation measurements, by automated recognition of the aircraft flight crew's prescribed activation sequence of specific mechanical systems during gate departure at taxi procedures, generating a point in time for the beginning of the segment and sequence for data capture (hereinafter referred to as a “triggering event”), followed by recognition of a subsequent activation of an aircraft's mechanical systems, and/or surpassing a prescribed length of elapsed time; which concludes the segment of the sought after pressure and rotations data measurements. A separate triggering event can be used to conclude the time period of data capture. Triggering events which begin and conclude the time periods of the pressure data capture can include the recognition of some or all of the following actions: [0159] a. indication that the aircraft cabin door has closed; [0160] b. indication that the aircraft parking brake has been set; [0161] c. indication that the aircraft parking brake has been released; [0162] d. respective strut pressure oscillations; [0163] e. prescribed period of time from the indication that the aircraft cabin door has closed; [0164] f. prescribed period of time from the indication that the aircraft parking brake has been engaged; [0165] g. prescribed period of time from the indication that the aircraft parking brake has been released; [0166] h. prescribed period of time in which pressure oscillations continue. [0167] i. “on-demand” manual activation
[0168] The invention provides methods to establish an off-aircraft Centralized Data-base of collected landing gear strut pressure oscillation patterns with corresponding rotation data, supported by sophisticated algorithms defining strut friction profiles, which evaluate the currently measured range of un-filtered landing gear pressure data-streams, recorded and received from the on-aircraft computer during aircraft movement. The first off-aircraft computer further processes the current landing gear data to determine a single pressure value, net of friction, corresponding to the amount of weight supported by a respective landing gear strut.
[0169] By selecting a specific window of data, which is sent to the off-aircraft computer, processing times are reduced, allowing weight and balance determinations to be made in real time for the benefit of the flight crew and the aircraft. Also, by sending the selected data to an off-aircraft computer, enhanced processing of the data can occur as data from other aircraft can be used and compared for additional processing.
[0170] The present invention utilizes existing aircraft flight crew procedures, which trigger the commencement and conclusion for automated measurement and capture of landing gear strut pressure and rotation sensor data, to further identify the desired window of strut pressure data and strut telescopic extension information, for wireless transmission from the on-aircraft computer.
[0171] The present invention provides apparatus and methods of increased automation to expedite airline operations and lower the risk of human error, by reducing interactions with a human and further reducing the amount of wireless data needed for transmission to the first off-aircraft computer Centralized Data-base.
[0172] The present invention utilizes methods within the Centralized Data-base to identify an “off-set value” with conversion to a measurement as pounds, associated with break-out friction, for various types of telescopic landing gear struts.
[0173] The present invention provides apparatus and methods with use of a first off-aircraft computer software, to promote the evolution and advancement of software algorithms, which improve the identification and determination of pressure errors caused by strut friction; which substantially reduces the re-certification costs associated with amending software, which has been previously certified by a Regulatory Authority and is residing within an on-aircraft computer.
[0174] The present invention provides for a Centralized Data Service provider, using a first off-aircraft computer to compile substantial quantities of strut pressure oscillation patterns from multiple airlines with aircraft landing gear of the identical type, beyond the limited data, which can be accumulated from a single airline, who may operate a limited number of aircraft, within a limited territorial range of temperature and environmental conditions.
[0175] The present invention provides apparatus and methods to detect, record, store, package and transmit a unique sequence of landing gear strut pressure and rotation sensor data, to optimize the identification, measurement and further correction for un-seen pressure errors caused by landing gear strut seal friction, which can misrepresent landing gear strut pressure, which is assumed as equivalent to the amount of weight supported, whereas an example is described herein: [0176] As weight is initially applied to a landing gear strut, the pressure within the strut will remain constant and the strut will not telescopically compress, until enough weight has been added to overcome resistance from landing gear strut seal break-out friction. Once break-out friction has been overcome, the strut pressure will begin to increase equivalent to the pounds of weight added, but at parallel and “off-set amount” which is a lower pressure; corresponding to the value of the “friction resistance.” When the pressure increases are examined closely it is revealed that the pressure increases are not an even upward slope, nor a smooth curve of pressure increases as additional weight is applied; but rather a stair-step pattern is recognized, as each subsequent step of break-out friction is overcome, [0177] Reversely, as weight is removed from the landing gear strut, the pressure within the strut will remain constant until enough weight has been removed for the trapped pressure to overcome break-out friction in the reverse direction. Even though weight has been removed, the resistance of break-out friction will contain a higher pressure within the strut, equivalent to the resistance of break-out friction. Strut pressure will remain artificially high, and decrease from that higher value, in a parallel relationship to the amount of weight removed.
[0178] Passengers board an aircraft while the aircraft is parked at a loading area. Loading areas vary depending on the size of the aircraft and the size of the airport. Large aircraft typically load passengers through an elevated boarding gate positioned at a matching height to the aircraft cabin door. Not all airports have elevated boarding gates, thus passengers walk from the airport terminal directly up to the aircraft and board by climbing a portable stairway positioned at the cabin door. Smaller aircraft, often operated by regional airlines, are equipped with cabin doors that are hinged at the bottom of the door, allowing the door to rotate downward to the ground. Regional airline passengers walk directly from the airport terminal to the aircraft and climb step risers, which are molded into the interior side of the cabin door; eliminating the need for a portable stairway. Upon completion of the loading with passengers and baggage, the aircraft parking brake is released, allowing the aircraft to taxi away from the loading area. As used herein, “gate” refers to loading area, whether the aircraft in the loading area is serviced by an elevated boarding gate or something else.
[0179] As the aircraft begins to taxi, the weight of the aircraft, suspended atop the three pockets of compressed gas will allow the aircraft to bounce as the landing gear roll over un-even sections of the taxi-way. While such bouncing is welcome to exercise the landing gear struts and overcome strut seal friction, obtaining accurate data and processing that data to obtain weight and balance information is difficult due a variety of factors. For example, when the aircraft brakes are applied to decelerate or stop the aircraft, loads resting upon the MLG will transfer forward to the NLG, changing the pressure within the respective struts. As the aircraft accelerates, loads resting upon the NLG will transfer aft to the MLG; again changing the pressure within the respective struts. As another example, a method to correct for landing gear strut pressure errors caused by the resistance of break-out friction is to average oscillating high-peak and low-peak pressures within the landing gear strut, while the aircraft moves horizontally and the telescopic landing gear struts are exercised. However, break-out friction values are not equivalent in opposing directions. Therefore, additional adjustments to pressure measurements are made to correct for asymmetries to increasing and decreasing strut pressures. Still another example is that seal friction resistance increases when retaining fluids at a higher pressure range. Seal friction resistance decreases when retaining fluids as pressure ranges lower. Further still, strut pressure can be measured at a sample rates from of 100 samples per second, up to 100,000 samples per second. As an example: 10 seconds of pressure data capture can provide 1,000 measurements. The most sophisticated aviation electronics and pressure sensors struggle with issues such as “electronic noise” which can increase errors. Electronic noise can be filtered from pressure data by identifying abstruse pressure values, which are considered outliers; and removing that very small percentage of the 1,000+ strut pressure measurements captured and recorded.
[0180] The present invention seeks to overcome the obstacles to obtaining accurate weight and balance information. Several embodiments of the invention are discussed. In a first embodiment there is shown the commencement for the capture of a prescribed sequence of landing gear pressure data, taken as the aircraft is pushed away from the airport gate, typically attached with an aircraft tow-bar and moved by an airport tug. A prescribed sequence of mechanically activated and timed triggers are established to capture pressure data and are initiated by recognition of the closing of the cabin door, with its associated door closed indicator, and subsequent release of the aircraft parking brake identifying the start of aircraft movement, and after a defined period of time concluding the capture sequence of strut pressure data triggered by the pilot re-setting the aircraft parking brake to allow removal of the airport tug and tow-bar; thus identifying an end to this specific segment of aircraft movement prior to the aircraft engine-powered taxi from the gate area.
[0181] In a second embodiment there is shown a review of the captured pressure and rotation data, which is analyzed upon completion of the first embodiment. The continued taxi of the aircraft is recognized by short periods of strut pressure oscillations, starting with the NLG rolling over an un-even section of the taxi-way, followed immediately by a similar oscillation by the MLGs rolling over the same un-even surface. This pattern of NLG oscillation followed by MLG oscillation occurs as the aircraft continues to taxi towards the take-off runway.
[0182] While the aircraft is in motion, there is no change in aircraft weight other than a small and measured amount of fuel consumed during the taxi period before take-off. Strut pressures will stabilize, as the resistance from friction will work to restrict telescopic movement. Subsequent identification of increases and decreases in strut pressure provides conclusive evidence that seal friction has again been overcome.
[0183] To provide an additional cross-reference to confirm seal friction has been overcome, rotation sensors optionally measure changes in the angle of opposing arms for landing gear torque-link. Use of simple geometry relating measured angle changes from torque-link rotation, which corresponds to the length of telescopic extension of the landing gear. Oscillation in rotation sensor measurements will parallel the oscillations in landing gear strut pressures, as strut pressure will change equivalent to changes of volume within the strut.
[0184] The present invention uses both an on-aircraft computer and a first off-aircraft computer; incorporating sophisticated algorithms, with advanced methods to correct for landing gear strut friction, by determining an optimum timing and sequence for confirming landing gear strut seal friction has been overcome, identified, and measured; within a minimal period of time, to reduce disruption and delays to airline flight schedules.
[0185] The Boeing 737 Next Generation family of aircraft comprises: 737-600, 737-700, 737-800, and 737-900. The Boeing Company has delivered 6,996 of the 737 Next Generation aircraft as of January 2019. This includes 13,992 MLG which average 6 flights per day, offering the potential of 83,952 Left and Right MLG strut pressure pattern profiles per day, to enter into this invention's 737-NG MLG strut pressure profile Centralized Data-base. The present invention compiles and associates landing gear pressure profiles from landing gear data sources beyond a single aircraft, and beyond just a single airline; allowing for an enhanced ability to compare identical aircraft using identical landing gear designs, to better identify, measure, and correct for pressure distortions caused by strut seal friction. The present invention offers methods to evolve and advance the algorithms used in the interpretation of landing gear strut seal friction patterns and profiling tools, used in measuring and confirming friction values, to increase accuracy for weight determinations on future flights. Use of a first off-aircraft computer by a Centralized Data Service provider, simplifies the pathway for adjustments to the first off-aircraft computer algorithms and software, reducing the long lead-time and costly expense for any re-certification of software programs residing within on-aircraft computers, that would be required by Regulatory Authorities.
[0186] The methods and apparatus described within this new invention, allow for increases to the automated functions of measuring aircraft landing gear strut seal friction and methods to decrease the amount of wireless transmission of landing gear data to the first off-aircraft computer operated by Centralized Data Service. Regulatory Authorities monitor substantial amounts of aircraft weight and CG data, which is compiled and stored, from multiple airlines in their day-to-day flight operations. Aircraft weight and CG information, generated by this invention, and adopted as an “advisory tool”, is not part of the airline's and Regulatory Authority's agreed procedures, thus is not required by the Regulatory Authority. The Centralized Data Service provider can use the measured weight data to assist the airline to re-validate their current assumptions for passenger weights and baggage weights, by subtracting the total aircraft weight from other weight elements such as: measured weight of empty aircraft, known fuel quantities, known catering weights, measured cargo weights and known flight crew weights.
[0187] The present invention provides a means to define and expedite a method to enhance the accuracy in the determination of an aircraft take-off weight, calculated with use of landing gear strut pressure, and accomplishes this automated task without disrupting airline operations, which might occur if upon the gate departure, the aircraft were delayed during its taxi to the take-off runway.
[0188] The present invention offers on-aircraft apparatus and methods utilizing an activation device and sensors for monitoring the status of various items, such as brake and door components, of the aircraft, as well as collecting un-filtered landing gear strut pressure and torque-link rotation data, with wireless transmissions to update a first off-aircraft computer using a variety of interrelated computer software programs, to create a more efficient capability of identifying and measuring landing gear strut seal break-out friction.
[0189] To summarize this invention, apparatus (shown in
[0216] Referring now to the drawings, wherein like reference numerals designate corresponding parts throughout the several views and more particularly to
[0217] NLG 3, along with LMLG 4 and RMLG 5 distribute the weight of aircraft through tires 6 resting on the ground 7. A processing component used in this invention and attached to aircraft 1 is a data acquisition/transmission on-aircraft computer 8. A device for data entry and indication, which can be used in this invention but not all are required, and attached to aircraft 1 is an activation device, 20, which may comprise digital key-pad 12, which incorporates an activation mechanism 16, facilitating an “on-demand” request for the aircraft 1 Weight and CG measurements and such information transmitted to a cockpit display 18 located on the face of key-pad 12.
[0218] Referring to
[0219] The activation device 20 is structured and arranged to selectively and/or automatically generate an event trigger upon activation. The activation device 20 of preferred embodiments comprises the activation mechanism 16 which can be a button, a toggle switch, a lever, computer icon, or other mechanism selectively controlled such that, upon initiation, for example movement, updated weight determinations are obtained. The step of detecting an event trigger while the aircraft is loading, has either the pilot or cabin crew verifying the aircraft weight during the loading process, comprising the step of selectively initiating the transmission of strut pressure data by, for example, manually pressing the activation mechanism 16.
[0220] As suggested above, the activation device 20 need not comprise an activation mechanism 16 that requires physical movement. In certain embodiments, the activation device 20 comprises a specially programmed assembly comprising a CPU, a user interface such as a computer screen having a graphical user interface (GUI) display 18, and necessary programming to permit the user to, by, for example, pressing an icon 16 on the screen or, using a curser device, activating an icon 16, activate the activation device 20 which upon activation, generates an event trigger to trigger transmission of strut pressure data from the on-aircraft computer 8 as discussed in this disclosure.
[0221] Having the ability to selectively trigger transmission of strut pressure data from the on-aircraft computer 8 is beneficial when additional weight is applied to an aircraft 1 at an alternate location such as a remote de-icing area.
[0222] In certain embodiments of the method, the activation device 20 is structured and arranged to automatically trigger transmission of strut pressure data from the on-aircraft computer 8 based upon the location of the aircraft 1. In certain embodiments, the activation device 20 or on-aircraft computer 8 comprises special programming and algorithms that permit the activation device 20 to generate event triggers. For example, using information provided by the on-aircraft navigation system 22 or from off-aircraft navigation system 24 which tracks aircraft 1, and are communicatively linked with the activation device, the activation device is adapted to automatically trigger transmission of updated aircraft weight determinations upon the aircraft entering certain preselected geographic zones (geo zones) and/or physical locations. For example, in certain embodiment, upon the aircraft exiting the gate area, the activation device is automatically activated to generate an event trigger for transmission of strut pressure data. By way of further example, the activation device, in certain embodiments is adapted to automatically trigger transmission of strut pressure data from the on-aircraft computer when the aircraft enters the taxiway. In still other embodiments, the activation device is adapted to automatically trigger transmission of strut pressure data from the on-aircraft computer when the aircraft enters the main runway. In still other embodiments, the activation device is adapted to trigger transmission of strut pressure data from the on-aircraft computer when the aircraft enters a hangar or de-icing area.
[0223] Landing gear pressure sensors 43 and rotation sensors 45 (shown in
[0224] On-aircraft computer 8 communicates via a wired connection 14 with aircraft parking brake indicator 9 and cabin door closed indicator 10, which are standard components of aircraft 1. On-aircraft computer 8 transmits wirelessly to a first off-aircraft computer 15, via antenna 11. Wireless communication from on-aircraft computer 8 to first off-aircraft computer 15 is shown by “solid arrow” 13 representing un-filtered landing gear pressure sensor and rotation data transmitted to first off-aircraft computer 15. In the example shown, the first off-aircraft computer 15 is housed within the Centralized Data Service provider 17. First off-aircraft computer 15 can be a portable device such as a laptop computer or a handheld computer tablet, capable of computations utilizing sophisticated software algorithms. First off-aircraft computer 15 is not required to be located within the Centralized Data Service provider facility, but have periodic wireless communication capabilities to the data library, which is maintained by Centralized Data Service provider 17. Use of a Centralized Data Service provider 17 allows for the filtering and further refining of aircraft landing gear pressure data. Various levels of data refinement, define the various products that can be delivered to the airline. The airline and Centralized Data Service provider 17 determine the type of information to be delivered to the airline. Transmission of the various products to the airline is shown by “dashed arrow” 19.
[0225] A second, optional, off-aircraft computer 21 is housed and operated within airline facility 23. The airline shall determine the subsequent nature of weight and CG information communicated back to the aircraft 1 shown by “dashed-dot arrow” 25. Pilot responsibilities are multiple and occur quickly as an aircraft prepares to take-off. An airline may choose to advise the pilot that the aircraft weight and CG information has been validated as within predetermined level of accuracy, and the aircraft is safe for departure; as opposed to sending information to a pilot that there is a slight weight difference between the planned weight and the measured weight, which might be confusing to the pilot. Reducing such distractions and confusion for the pilots increase the safety in the overall operation of aircraft 1. Information communicated to aircraft 1 shown by “dashed-dot arrow” 25, may also include an on-demand request for aircraft weight and CG, thus the cycle of transmission is re-started again, but in this alternate sequence, the cycle is initiated by airline personnel or other authorized individuals using 2.sup.nd off-aircraft computer 21, within the airline facility 23, transmitted to on-aircraft computer 8, then subsequent transmission to 1.sup.st off-aircraft computer 15, and ultimately back to 2.sup.nd off-aircraft computer 21, housed at the airline facility 23.
[0226] Referring now to
[0227] Referring now to
[0228] Aircraft 1a transmits unfiltered landing gear data, shown as solid arrow 13a, to Centralized Data Service 17 computer 15.
[0229] Aircraft 1b transmits unfiltered landing gear data, shown as solid arrow 13b, to Centralized Data Service 17 computer 15.
[0230] Aircraft 1c transmits unfiltered landing gear data, shown as solid arrow 13c, to Centralized Data Service 17 computer 15.
[0231] Centralized Data Service 17 maintains an extensive library comprised of an expanding depository of landing gear friction pattern profiles, from identical aircraft. The library also compiles increasing pools for different aircraft types, each with a specific landing gear design, common to that aircraft type. The pools of aircraft pressure patterns are sub-divided into categories defined by a common landing gear design with pressure profiles ranging from congruent friction patterns, to those with excessive asymmetry, when compared to the general population within that pool. Identification of a landing gear friction profile specific to a single landing gear, is registered by each respective landing gear strut serial number, and by each specific aircraft hull registration number, for every landing gear which is registered with the Centralized Data Library 17. The friction patterns are analyzed to identify the amount of pressure differential between each pressure reversal experienced as the aircraft taxi and the strut oscillate. The strut pressure reversal (sometimes referred to the “delta pressure”) will change, depending on the current amount of experienced pressure. As pressure increases, the O-ring strut seal composite materials will deflect and change the shape of its surface profile; thus applying more surface area on the opposing metal surface of the landing gear strut piston, thus allowing it to withstand and maintain the higher strut pressures. The friction profiles are a library of look-up tables with the ranges of experienced pressure changes, thus correlating a specific friction correction value for a specific amount of experienced pressure. Each landing gear strut's friction patterns can be slightly different, thus the mapping of friction profiles for each respective landing gear are similar to building a fingerprint data-base of each respective landing gear within Centralized Data Library 17. With a significant amount of asymmetry or migration from the historical fingerprint of the friction patterns of a respective landing gear strut, triggers a notification to be sent to the aircraft operator of a potential seal problem existing within that specific landing gear, on that specific aircraft. The library provides this additional analysis tool for the Central Data Service 17 to better determine, identify and profile the amount of pressure distortion produced by landing gear strut seal friction, from the next received landing gear pressure data sets, from a specific aircraft type, queued for interpretation and determination of aircraft weight and center of gravity.
[0232] Referring now to
[0233] Changes to the amount of weight supported by landing gear 3 result in variations to landing gear strut internal pressure, as recorded by pressure sensor 43. As weight is applied to landing gear strut 3, telescopic piston 37 will recede into strut cylinder 35, reducing the interior volume within the telescopic landing gear strut and reducing the value of “Dimension X”, which is a measureable length of the exposed chrome finished portion of piston 37, outside of cylinder 35. As weight is applied to strut 3, Dimension X decreases as internal pressure within strut 3 will increases proportionally.
[0234] Rotation sensor 45 is attached to the landing gear torque-link 47, an element of the landing gear that prevents strut piston 37 from turning within strut cylinder 35. Rotation sensor 45 measures changes in the angle formed at the hinge point of upper and lower opposing arms of torque-link 47. Measured changes in the angle of torque-link 47 correlate to changes in Dimension X. Variations in Dimension X are illustrated by vertical double-arrow 49.
[0235] Boyle's Ideal Gas Law: P.sub.1V.sub.1=P.sub.2V.sub.2 confirms that a change in Dimension X is proportional to a change in strut pressure. Identification and measurement of changes in Dimension X allow an alternate means to confirm the landing gear strut has moved telescopically, and verifying seal friction has been overcome with such movement.
[0236] Referring now to
[0237] On-aircraft computer 8 is equipped with an internal clock and calendar, to reference the date and time of recorded pressure sensor and torque-link rotation data. Computer 8 is also equipped with a cellular telephone or use of alternate means of wireless communication such as “Gate-Link”. Wi-Fi or Bluetooth; to transmit captured and unfiltered landing gear data from on-aircraft computer 8, to the first off-aircraft computer 15 (shown in
[0238] On-aircraft computer 8 records and stores respective landing gear strut data into a memory-loop, and recorded data is stored for a specified period of time. If the previously recorded and stored data is unused, the on-aircraft computer 8 will over-write that period of recorded data, with subsequently measured and recorded new landing gear data stored in its place. The memory-loop is utilized to conserve memory space within on-aircraft computer 8.
[0239] On-aircraft computer 8 has multiple data acquisition and referencing functions, (illustrated in
[0243] On-aircraft computer 8 has multiple operating software programs, (illustrated in
[0247] On-aircraft computer 8 has data transmission functions, including: [0248] Data Transmission function “Eta” which communicates the captured, and un-filtered NLG, LMLG and RMLG strut pressure and rotation sensor data, wirelessly to the first off-aircraft computer 15 (shown in
[0249] Referring now to
[0250] First off-aircraft computer 15 has multiple data acquisition, processing, filtering, storage and 2.sup.nd Transmission functions (illustrated in
[0253] First off-aircraft computer 15 has multiple operating software programs and algorithms, which include: [0254] Software Program “Kappa” (described in
[0273] First off-aircraft computer 15 has data transmission capabilities, which include: [0274] Data Transmission function “Rho” which communicates aircraft weight, CG or other products related to landing gear strut pressure to airline computer 21 (shown in
[0275] Referring now to
[0276] Second off-aircraft computer 21 has on-demand manual activation mechanism 16 capabilities and data acquisition, as well as transmission functions which include: [0277] Data Acquisition function “Upsilon” receives final computations of aircraft weight and CG. [0278] Data Transmission function “Tua” allowing for an on-demand and manual request for aircraft weight and CG measurement.
[0279] In certain arrangements, second off-aircraft computer 21 is adapted to function as a virtual activation mechanism 16 communicatively linked to activation device 20. In other arrangements, second off-aircraft computer 21 is communicatively linked to the on-aircraft activation mechanism 16.
[0280] Referring now to
[0281] A method is shown for verification and validation that break-out friction of the aircraft landing gear strut has been recognized and overcome, in accordance with the first embodiment. Landing gear strut pressures are monitored during a typical pre-departure loading of the aircraft and followed by a gate departure with aircraft taxi from the gate. Landing gear strut pressure is shown as increasing vertically from the left side of the graph with a range in pressure from 800 psi through 2000 psi. Pressure changes are shown in relation to elapsed time, with the passage of Time is shown as the horizontal arrow 51 pointing to the right, across the bottom of the graph.
[0282] In the example shown, pressure measured from the NLG is shown as horizontal line 53. Pressure measured from the LMLG is shown as horizontal line 55 (RMLG pressure is not shown). The portion of aircraft weight (and added weight) supported by the NLG corresponds to a strut pressure measurement at the beginning of line 53 (also identified as pressure profile line p′) of approximately 1,160 psi. The portion of aircraft weight (and added weight) supported by the LMLG corresponds to a strut pressure measurement at the beginning of line 55 (also identified as pressure profile line p.sup.2) of approximately 1,670 psi.
[0283] The period of time of data, which is transmitted off the aircraft to off-aircraft computer 15 has a start time and an end time. The start time is initiated by an event trigger. Various starting event triggers can be used, such as release of the parking brake or the determination of pressure oscillations (psi deltas “A” and “B” as shown in
[0284] Shown in
[0285] Time-markers t.sup.−2 through t.sup.0 identify the period of aircraft loading, prior to the initial release of the parking brake. Time-marker t.sup.−2 is typically set at 40 minutes prior to t.sup.1, being the point in time for Software Epsilon to look backwards in time from t.sup.1 to identify the previously recorded pressure data as the aircraft loads with passengers, taking into consideration that most airlines begin passenger loading 30 minutes prior to gate departure.
[0286] NLG strut pressure profile p.sup.1 is shown with an initial stair-stepped line 53 moving upward as weight is added, followed by periodic pressure reversals. These pressure reversals occur when weight enters the aircraft through the cabin door, located above the NLG, then moves aft away from the NLG. NLG strut pressure profile p.sup.1 progresses to the right, along time-line 51. LMLG strut pressure profile p.sup.2 shows a similar stair-stepping of line 55. The stair-stepping patterns of pressure increases along NLG line p.sup.1 and LMLG line p.sup.2 are produced from the initial release of break-out friction, allowing the strut to telescopically compress; followed by a re-establishment of the seal friction resistance, which will then maintain a stabilized pressure until enough additional weight is applied to again overcome the break-out friction, causing another rise in pressure, as the strut continues to compress.
[0287] Software Program “Epsilon” (shown in
[0288] Software Program “Zeta” (which initiates later) is assigned with the task for execution of landing gear data collection and packaging, commencing with time-marker t.sup.0 by a signal from cabin door indicator 10 of the closing of the cabin door 2, followed by a signal from parking brake indicator 9 of the initial or first release of the aircraft parking brake t.sup.1 (shown in
[0289] Software Program “Epsilon” continues with a search for oscillations along NLG pressure profile p.sup.1, indicating the commencement of pressure pattern—psi delta “A” also referenced as oscillation-NLG “o-N.sup.1” which confirms aircraft 1 horizontal movement and slight vertical movement 33 of the aircraft nose (shown in
[0290] Software Program “Epsilon” continues with a search for oscillations in measurements from rotation sensors 45 (shown in
[0291] Time-marker t.sup.1 is the recognition of the release of aircraft parking brake and indicates when aircraft 1 commences the initial pushed-back from the gate. As tug 27 (shown in
[0292] Pressure pattern—psi delta “A” shown as NLG pressure oscillation o-N.sup.1 recognize the initial pressure oscillation, followed by multiple oscillations with a continued decline in high-peak and low-peak range of pressure oscillations, along line 53 being NLG p.sup.1.
[0293] Pressure pattern—psi delta “B” shown as LMLG pressure oscillation o-M.sup.1 recognize the initial pressure oscillation, followed by multiple oscillations with a continued decline in high-peak and low-peak range of pressure oscillations, along line 55 being LMLG p.sup.2.
[0294] As aircraft 1 completes the push-back from the gate, an abrupt stop generates a second transfer or rocking of suspended weight from NLG to MLGs, repeating the pressure oscillations shown as NLG o-N.sup.2 and MLG o-M.sup.2. Time-marker t.sup.3 is identified by the re-setting of the aircraft parking brake. Ground personnel then remove tow-bar 29 connected to tug 27 from aircraft 1 and clear the area around aircraft 1 making it ready for taxi away from the gate area.
[0295] Time-marker t.sup.4 is identified by the second release of the aircraft parking brake as the aircraft readies for taxi towards the take-off runway. Time-marker t.sup.4 triggers commencement of an additional 45-seconds of landing gear data measurements, until time-marker t.sup.5. The choice of 45-seconds of elapsed time is used as an example, where the aircraft operator may select an alternate period for time-marker t.sup.5. Time-marker t.sup.5 acknowledges the conclusion for the 1.sup.st Transmission data package. The un-filtered data is packaged and sent by wireless transmission, shown as solid-arrow 13 (shown in
[0296] As aircraft 1 moves horizontally away from the gate area, it will roll over expansion joints within the concrete taxi-way. These expansion joints are often un-even sections of the taxi-way and cause aircraft 1 to bounce as it passes over the sometimes un-aligned seams in the concrete. As aircraft 1 moves horizontally, NLG 3 will first encounter the un-even expansion joint, shown at time-marker t.sup.6, followed immediately by the MLGs 4 and 5 encountering the same un-even expansion joint at time-maker t.sup.7. Landing gear strut pressure will initially oscillate as the suspended weight of the aircraft bounces over the concrete expansion joints, until resistance from strut frictional forces stabilize the strut pressure. Pressure oscillations shown as NLG o-N.sup.3 and MLG o-M.sup.3 are identified by their stagger along time-arrow 51, lesser in range between the high-peak and low-peak pressures; and cataloged as the profile patterns for bumps along the taxi-way. Time-markers t.sup.8 and t.sup.9 are repeat patterns of time-markers t.sup.6 and t.sup.7 as the aircraft encounters the next un-even expansion joint. Time-markers t.sup.10 and t.sup.11 are repeat patterns of time-markers t.sup.8 and t.sup.9 as the aircraft encounters the next un-even expansion joint. These patterns of strut pressure oscillations will continue for a number of occurrences, until the aircraft reaches the beginning of the runway for take-off.
[0297] The potential of NLG pressure oscillation before the release of the parking brake at time-marker t.sup.1 is noted and accounted for in Software Program “Epsilon”. The recognition of the specified time-markers and capture of landing gear strut pressure through the oscillation periods, along with identification of torque-link angle changes, complete the definitions of Software Program “Epsilon”.
[0298] Upon recognition of time-marker t.sup.5 Software Program “Zeta” (shown in
[0299] Also, upon recognition of time-marker t.sup.5 and after the packaging of strut data, Software Program “Eta” (shown in
[0300] Referring now to
[0301] Software Programs “Kappa and Lambda”, residing within first off-aircraft computer 15 (shown in
[0302] Landing gear beak-out friction is not symmetrical. The O-ring seals of today's landing gear strut have characteristics, which show friction values progressively higher as pressure within the strut increases, and progressively lower as pressure within the strut decreases. These asymmetrical characteristics are illustrated by the slightly greater separation in the boundary lines of psi delta “D” shown on the higher-pressure range, to the slightly lesser separation in the boundary lines of psi delta “E” shown on the lower-pressure range. The pressure ranges within the limits of psi delta “D” and psi delta “E” will change with different environmental conditions such as temperature and humidity; as well as different weight ranges supported by the landing gear. When pressure increases within the strut, the seal materials deflect in shape to retain the higher pressures, thus frictional forces are slightly increased as the strut begins to compress. When pressure reduces within the strut, the seal materials deflect in an opposing direction to release with the lower pressures, thus frictional forces are slightly decreased as the strut begins to extend.
[0303] Filtering to remove the ultra-high-peak pressure outliers and ultra-low-peak pressures outliers allow for Software Programs “Mu” (described in
[0304] Referring now to
[0305] Software Program “Mu” continues a review of pressure profile p.sup.2 between time-markers t.sup.1 and t.sup.3 are shown psi delta “D” and psi delta “E”. Once the ultra-high and ultra-low pressure anomalies and outliers from psi delta “D” and psi delta “E” are filtered and eliminated, the resulting range of high-peak pressure and low-peak pressure oscillation are averaged by Software Program “Nu” and shown as psi delta “F”. The oscillating pressures of psi delta “F” are averaged to determine a single value of landing gear strut pressure for LMLG 4, which is net of the distortions of strut seal friction.
[0306] The continuation pressure profile shown along line p.sup.2 to the right of the illustration of psi delta “F” is not the computed averaged of psi delta “F” (the line shown is not centered by the average); but instead the continued pressure measurement from pressure sensor 43 (shown in
[0307] The differential pressure (measured as psi) between the median pressure shown by p.sup.nf to either the high-peak or low-peak pressure values of psi delta “F”; multiplied times the area of the horizontal cross-section within the landing gear strut, equals to the amount of the friction error recognized in pounds. Measurement recorded in pounds can be converted to kilograms by dividing the pound measurement by 2.2046.
1,000 lb.±2.2046=453.59 kg
[0308] Pressures (and rotation data) from time-marker t.sup.1 through time-marker t.sup.5 are recorded and stored into a data package to be wirelessly transmitted from on-aircraft computer 8 (shown as 1st Transmission of data, in
[0309] Referring now to
[0310] Step 1.—Recognition of time-marker t.sup.1 (initial release of the aircraft parking brake) commencing a specific sequence for the capture of measured pressure and torque-link rotation data for the period of time of beginning, at t.sup.−2 (start of the aircraft loading process, 40-minutes earlier) and concluding at t.sup.5 (shown in
[0311] Step 2.—Recognition of time-marker t.sup.0 (closing of the cabin door) confirming the cabin door is closed, before the initial release of the parking brake.
[0312] Step 3.—Capture from memory-loop of the prior 40-minutes of measured strut pressure and torque-link rotation data from t.sup.−2 through the cabin door closing t.sup.0.
[0313] Step 4.—Recognition of a stabilized strut pressure and no torque-link rotation, during the period from t.sup.0 through the release of the aircraft parking brake t.sup.1.
[0314] Step 5.—Commencing from the release of the aircraft parking brake t recognition of when respective strut pressures are no longer stable and begin their first oscillation o.sup.1 (oscillation o.sup.1 refers to pressure reversals within NLG, LMLG and RMLG, shown in
[0315] Step 6.—Recognition of time-marker t.sup.2 identified with the initial respective pressure oscillations o.sup.1, and followed by a period of stabilized pressure, then followed by subsequent pressure oscillations o.sup.2 (oscillation o.sup.2 refers pressure reversals within NLG, LMLG and RMLG, shown in
[0316] Step 7.—Recognition of time-marker t.sup.3 (re-setting of the parking brake) which concludes the aircraft push-back from the gate. During the period immediately after time-marker t.sup.3, ground personnel detach the aircraft from tow-bar 29 and tug 27 (shown in
[0317] Step 8.—Recognition of time-marker t.sup.4 (second release of the aircraft parking brake) signaling the aircraft is ready for taxi.
[0318] Step 9.—Recognition of time-marker t.sup.5 as a period of 45-seconds after t.sup.4, while the aircraft is taxiing away from the gate. During this period, the landing gear strut pressures again may again oscillate (not shown), allowing for more pressure data to be captured and used in correcting for landing ear strut seal friction (45-seconds is used as an example, where a different period of time may be selected).
[0319] Step 10.—Time-marker t.sup.5 also instructs on-aircraft computer 8, Software Program “Zeta” (shown in
[0320] Step 11.—Time-marker t.sup.5 also instructs on-aircraft computer 8, Software Program “Eta” to execute packaging and 1.sup.st Transmission of captured landing gear pressure and torque-link rotation data from on-aircraft computer 8 to first off-aircraft computer 15.
[0321] Specific periods for time-markers described herein are use only as examples, where different aircraft operators with different aircraft types may choose to shorten or lengthen the time periods associated with the various time-markers t.sup.−2 through t.sup.11.
[0322] Referring now to
[0323] Step 12.—Recognition of time-marker t.sup.6 identifying the commencement of NLG pressure oscillation o-N.sup.3 generated by a bumping of aircraft 1, as NLG 3 passes over an un-even portion of the airport taxi-way.
[0324] Step 13.—Recognition of time-marker t.sup.7 identifying the commencement of MLG pressure oscillation o-M.sup.3 generated by a bumping of aircraft 1, as LMLG 4 passes over an un-even portion of the airport taxi-way.
[0325] Step 14.—Recognition of time-marker t.sup.8 which is a duplication of Step 12, generated by a supplemental bumping of aircraft 1, as NLG 3 passes over another un-even portion of the airport taxi-way.
[0326] Step 15.—Recognition of time-marker t.sup.9 which is a duplication of Step 13, generated by a supplemental bumping of aircraft 1, as LMLG 4 passes over another un-even portion of the airport taxi-way.
[0327] Step 16.—Recognition of time-marker t.sup.10 which is a duplication of Step 12, generated by a supplemental bumping of aircraft 1, as NLG 3 passes over another un-even portion of the airport taxi-way.
[0328] Step 17.—Recognition of time-marker t.sup.11 which is a duplication of Step 13, generated by a supplemental bumping of aircraft 1, as LMLG 4 passes over another un-even portion of the airport taxi-way.
[0329] Step 18.—Is a duplication of Step 10 (shown in
[0330] Step 19.—Is a duplication of Step 11 (shown in
[0331] The additional Steps 13-17 for the 2.sup.nd Transmission of landing gear pressure and torque-link rotation data are compared to the previous Steps 5-9 for the 1.sup.st Transmission—Data, and are used to validate the findings from the 1.sup.st Transmission—Data for each respective strut. This comparison is not measured against other landing gear friction patterns, from other aircraft, but limited to only the single aircraft and is a cross-check function for the respective landing gear of this single aircraft. The provision of a 2.sup.nd Transmission of data is optional.
[0332] Referring now to
[0333] Referring now to
[0334] Referring now to
[0335] In the following Example, all of Steps 1a-5a are processed by software algorithms within on-aircraft computer 8. In this “specific example” aircraft 1 is operating one of its many flights, but on this “specific flight” the aircraft is operating in a classified area or under classified conditions such that the mission and location of the aircraft 1 is classified. In such locations and under such conditions, the aircraft's location and heading are not permitted to be publicly identified by, for example, tracking wireless communications through various communication towers or methods. [0336] Step 1a—recognizes an “on-demand” manual request for the activation of the system to commence the weighing of aircraft 1. [0337] Step 2a—initiates inquiries to the pressure sensors 43 on respective NLG 3 and MLGs 4 and 5 (shown in
[0341] Referring to the figures, in a preferred embodiment, an aircraft operation method of providing weight and center of gravity information for a flight of the aircraft is provided, the method comprising the steps of providing an activation device, the activation device being structured and arranged to generate an event trigger upon activation; after generation of the event trigger by the activation device, measuring and recording internal pressure from the respective landing gear struts with an on-aircraft computer; continuing to measure and record internal pressure from the landing gear struts for a period of time; transmitting the recorded strut pressure measurements for the period of time to an off-aircraft computer; processing the transmitted recorded strut pressure measurements and correcting for the friction interference created by the strut seals, using the off-aircraft computer; determining a total weight of the aircraft and the aircraft center of gravity using the off-aircraft computer; providing the total weight of the aircraft and the aircraft center of gravity from the off-aircraft computer to an operator of the aircraft.
[0342] In certain embodiments of the method, the activation device is positioned onboard the aircraft. In certain embodiments, the event trigger is generated by the activation device by automatic or manual activation of the activation device.
[0343] In certain embodiments of the method, the event trigger is manually generated by the activation device by movement of an activation mechanism such as a button, a switch, or a computer icon.
[0344] In certain embodiments, the event trigger is automatically generated by the activation device upon entry of the aircraft into a preselected geo zone.
[0345] In another embodiment, an aircraft operation method of determining a weight of revenue payloads for a flight of the aircraft is provided, the method comprising the steps of: detecting an event trigger, the event trigger signaling entry of the aircraft into a preselected geo zone; after the detection of the event trigger, measuring and recording internal pressure from the respective landing gear struts; continuing to measure and record internal pressure from the landing gear struts for a period of time; using the off-aircraft computer, correcting for the friction interference created by the strut seals and determining a total weight of the aircraft from the internal pressures; determining an operating empty weight of the aircraft; determining a weight of fuel onboard the aircraft; determining a weight of non-passenger cargo onboard the aircraft; determining a count of a number of passengers and passenger bags on the aircraft; using the total weight of the aircraft, the operating empty weight of the aircraft, the fuel weight, the non-passenger cargo weight, and the number of passengers and passenger bags, determining a per passenger weight and per passenger bag weight; recording the per passenger weight and per passenger bag weight for the flight.
[0346] In certain embodiments, the method comprises the step of determining and compiling an average weight of a passenger on the flight, with carry-on items.
[0347] In certain embodiments, the method comprises the step of determining and compiling an average weight of a checked bag on the flight.
[0348] In certain embodiments, the method comprises the step of determining a weight of revenue payload associated with a particular set of destination city pairs.
[0349] In certain embodiments, the method comprises the step of determining the weight of revenue payload associated with a particular time of day.
[0350] In certain embodiments, the method comprises the step of determining the weight of revenue payload associated with a particular season of a year.
[0351] Although an exemplary embodiment of the invention has been disclosed and discussed, it will be understood that other applications of the invention are possible and that the embodiment disclosed may be subject to various changes, modifications, and substitutions without necessarily departing from the spirit and scope of the invention.