Method, system, and graphical indicator for providing a lateral center of gravity of an aircraft

The present disclosure provides methods and systems for providing a lateral center of gravity of an aircraft on an aircraft display. A fuel distribution in the aircraft fuel tanks is determined. A lateral center of gravity of the aircraft is determined based on the fuel distribution. The lateral center of gravity is sent to the aircraft display. The present disclosure further provides an aircraft display for displaying the lateral center of gravity of an aircraft.

TECHNICAL FIELD

The present disclosure relates generally to aircraft instrumentation, and more specifically to a lateral center of gravity display and systems and methods for providing the lateral center of gravity of an aircraft on an aircraft display.

BACKGROUND OF THE ART

The location of the center of gravity of an aircraft can affect its stability. If the positioning of the center of gravity exceeds a certain threshold set by the aircraft manufacturer, the aircraft performance may be impacted.

The center of gravity of the aircraft may be specified in the longitudinal, lateral and vertical directions. The longitudinal center of gravity refers to the balance of the aircraft along the longitudinal or lengthwise axis (known as the pitch direction or forward and aft direction). The lateral center of gravity refers to the balance of the aircraft in the lateral direction (known as right to left direction). The vertical center of gravity refers to the positioning of the center of gravity of the aircraft in the vertical direction (known as the up and down direction). Aircraft manufacturers may set longitudinal, lateral and vertical center of gravity limits.

An imbalance in the lateral center of gravity has historically been considered less critical than an imbalance in the longitudinal center of gravity, as most of the mass of the aircraft is located close to its center. However, the lateral center of gravity of the aircraft can be affected by fuel stored in fuel tanks located inside the wings not being evenly distributed between both sides of the aircraft. Existing alerting systems of aircraft do not readily facilitate such lateral center of gravity imbalance to be remedied.

SUMMARY

The present disclosure provides methods and system for providing a lateral center of gravity of an aircraft on an aircraft display. A fuel distribution in the aircraft fuel tanks is determined. A lateral center of gravity of the aircraft is determined based on the fuel distribution. The lateral center of gravity is sent to the aircraft display. The present disclosure further provides a graphical indicator for an aircraft display for displaying the lateral center of gravity of an aircraft.

In accordance with a broad aspect, there is provided a method for providing a lateral center of gravity of an aircraft on an aircraft display. The method comprises determining a fuel distribution in fuel tanks of a first wing and a second wing of the aircraft, determining a lateral center of gravity of the aircraft based at least in part on the fuel distribution, and sending a signal indicative of the lateral center of gravity to the aircraft display.

In some embodiments, the first wing comprises a first tank that is an inboard tank and a second tank that is an outboard tank, and the second wing comprises a third tank that is an inboard tank and a fourth tank that is an outboard tank.

In some embodiments, determining the fuel distribution comprises determining a first mass of fuel in the first tank from fuel density and fuel volume measurements in the first tank, determining a second mass of fuel in the second tank from fuel density and fuel volume measurements in the second tank, determining a third mass of fuel in the third tank from fuel density and fuel volume measurements in the third tank, determining a fourth mass of fuel in the fourth tank from fuel density and fuel volume measurements in the fourth tank, and determining the fuel distribution based on the first mass of fuel, the second mass of fuel, the third mass of fuel, the fourth mass of fuel and a configuration of the first tank, the second tank, the third tank and the fourth tank.

In some embodiments, determining the lateral center of gravity of the aircraft comprises determining a first moment arm based on the first mass of fuel and a first distance between a first tank center of mass and a substantially centered longitudinal axis of the aircraft, determining a second moment arm based on the second mass of fuel and a second distance between a second tank center of mass and the substantially centered longitudinal axis of the aircraft, determining a third moment arm based on the third mass of fuel and a third distance between a third tank center of mass and the substantially centered longitudinal axis of the aircraft, determining a fourth moment arm based on the fourth mass of fuel and a fourth distance between a fourth tank center of mass and the substantially centered longitudinal axis of the aircraft, and determining the lateral center of gravity using the first moment arm, the second moment arm, the third moment arm and the fourth moment arm.

In some embodiments, the method further comprises displaying the lateral center of gravity on the display with respect to at least one threshold.

In some embodiments, the method further comprises displacing a pointer indicative of the lateral center of gravity on the display with respect to the at least one threshold when the lateral center of gravity of the aircraft changes.

In some embodiments, the at least one threshold comprises at least one on ground threshold for use when the aircraft is on ground and at least one inflight threshold for use when the aircraft is in flight.

In some embodiments, the method further comprises determining the at least one threshold as a function of a total fuel mass.

In some embodiments, the method further comprises triggering a rebalancing of fuel between at least some of the first tank, the second tank, the third tank, and the fourth tank when the lateral center of gravity exceeds a first one of the at least one threshold.

In some embodiments, the method further comprises triggering an alert when the lateral center of gravity exceeds a second one of the at least one threshold.

According to another broad aspect, there is provided a system for providing a lateral center of gravity of an aircraft on an aircraft display. The system comprises a processing unit and a non-transitory computer-readable memory having stored thereon program instructions. The program instructions are executable by the processing unit for determining a fuel distribution in fuel tanks of a first wing and a second wing of the aircraft, determining a lateral center of gravity of the aircraft based at least in part on the fuel distribution, and sending a signal indicative of the lateral center of gravity to the aircraft display.

In some embodiments, the first wing comprises a first tank that is an inboard tank and a second tank that is an outboard tank, and the second wing comprises a third tank that is an inboard tank and a fourth tank that is an outboard tank.

In some embodiments, determining the fuel distribution comprises determining a first mass of fuel in the first tank from fuel density and fuel volume measurements in the first tank, determining a second mass of fuel in the second tank from fuel density and fuel volume measurements in the second tank, determining a third mass of fuel in the third tank from fuel density and fuel volume measurements in the third tank, determining a fourth mass of fuel in the fourth tank from fuel density and fuel volume measurements in the fourth tank, and determining the fuel distribution based on the first mass of fuel, the second mass of fuel, the third mass of fuel, the fourth mass of fuel and a configuration of the first tank, the second tank, the third tank and the fourth tank.

In some embodiments, determining the lateral center of gravity of the aircraft comprises determining a first moment arm based on the first mass of fuel and a first distance between a first tank center of mass and a substantially centered longitudinal axis of the aircraft, determining a second moment arm based on the second mass of fuel and a second distance between a second tank center of mass and the substantially centered longitudinal axis of the aircraft, determining a third moment arm based on the third mass of fuel and a third distance between a third tank center of mass and the substantially centered longitudinal axis of the aircraft, determining a fourth moment arm based on the fourth mass of fuel and a fourth distance between a fourth tank center of mass and the substantially centered longitudinal axis of the aircraft, and determining the lateral center of gravity using the first moment arm, the second moment arm, the third moment arm and the fourth moment arm.

In some embodiments, the program instructions are further executable by the processing unit for displaying the lateral center of gravity on the display with respect to at least one threshold.

In some embodiments, the program instructions are further executable by the processing unit for displacing a pointer indicative of the lateral center of gravity on the display with respect to the at least one threshold when the lateral center of gravity of the aircraft changes.

In some embodiments, the at least one threshold comprises at least one on ground threshold for use when the aircraft is on ground and at least one inflight threshold for use when the aircraft is in flight.

In some embodiments, the program instructions are further executable by the processing unit for determining the at least one threshold as a function of a total fuel mass.

In some embodiments, the program instructions are further executable by the processing unit for triggering a rebalancing of fuel between at least some of the first tank, the second tank, the third tank, and the fourth tank when the lateral center of gravity exceeds a first one of the at least one threshold.

In some embodiments, the program instructions are further executable by the processing unit for triggering an alert when the lateral center of gravity exceeds a second one of the at least one threshold.

According to another broad aspect, there is provided a graphical indicator for an aircraft display. The graphical indicator comprises a first segment extending from a first end to a second end, a central marker substantially centered between the first end and the second end of the first segment to represent a balanced lateral center of gravity, and a pointer displaceable along the first segment between the first end and the second end, a position of the pointer along the first segment being indicative of one of a balanced lateral center of gravity, a left wing imbalance, and a right wing imbalance as a function of a relative position of the pointer with the central marker.

In some embodiments, the graphical indicator further comprises a first pair of threshold markers positioned along the first segment, wherein each threshold marker of the first pair of threshold markers is spaced equidistantly from the center marker towards a respective one of the first end and the second end.

In some embodiments, the graphical indicator further comprises a second pair of threshold markers positioned along the first segment, wherein each threshold marker of the second pair of threshold markers is spaced equidistantly from a respective threshold marker of the first pair of threshold markers towards a respective one of the first end and the second end.

In some embodiments, the graphical indicator further comprises a second segment extending from a third end to a fourth end, wherein the first segment is for use when the aircraft is in flight and the second segment is for use when the aircraft is on ground.

In some embodiments, the first segment and the second segment are positioned one above the other, and wherein the pointer is positioned between the first segment and the second segment.

In some embodiments, the central marker is substantially centered between the third end and the fourth end of the second segment.

In some embodiments, a visual element of the graphical indicator indicates usage of one of the first segment and the second segment as a function of an aircraft status.

In some embodiments, the graphical indicator further comprises a third pair of threshold markers positioned along the second segment, wherein each threshold marker of the third pair of threshold markers is spaced equidistantly from the center marker towards a respective one of the third end and the fourth end.

In some embodiments, the graphical indicator further comprises a fourth pair of threshold markers positioned along the second segment, wherein each threshold marker of the fourth pair of threshold markers is spaced equidistantly from a respective threshold marker of the first third of threshold markers towards a respective one of the third end and the fourth end.

In some embodiments, the first segment and the second segment display the lateral center of gravity of the aircraft using a same scale.

Features of the systems, devices, and methods described herein may be used in various combinations, and may also be used for the system and computer-readable storage medium in various combinations.

DETAILED DESCRIPTION

Methods and systems for providing a lateral center of gravity of an aircraft on an aircraft display are described herein. The lateral center of gravity is determined based on distribution of fuel in the fuel tanks of the aircraft. The present disclosure further provides a graphical indicator for displaying the lateral center of gravity of an aircraft.

With reference toFIG.1A, an exemplary aircraft10is shown. The aircraft10may be any type of aircraft such as a propeller plane, jet plane, turbojet plane, turbo-propeller plane, and the like. For example, the aircraft10may be a narrow-body, twin-engine jet airliner. The aircraft10may be a fixed-wing aircraft. The aircraft10may comprise flight control components16, wings31,32, fuselage18, engines20and empennage22of known or other type. In the embodiment illustrated, a single engine20is mounted under each of the wings31,32. However, two or more engines20may be mounted to one or more of wings31,32. Alternatively, or in addition, one or more engines20may be mounted to fuselage18or be installed on the aircraft10in any suitable manner. A cockpit12may be positioned at any suitable location on the aircraft10, for example at a front portion of the fuselage18. The cockpit12is configured for accommodating one or more pilots who control the operation of the aircraft10by way of one or more operator controls.

With reference toFIG.1B, the aircraft10comprises a first wing31and a second wing32. The first wing31comprises a first tank41and a second tank42. The second wing32comprises a third tank43and a fourth tank44. The tanks41,42,43,44are for holding fuel for the aircraft10. The tanks41,42,43,44may have various volumetric shapes and may be positioned inside the wings31,32in any suitable manner. In the illustrated embodiment, the first tank41and the third tank43are inboard tanks, the second tank42and the fourth tank44are outboard tanks. For the purposes of the present disclosure, the first wing31is referred to as a right wing on a right side of the aircraft10and the second wing32is referred to as a left wing on a left side of the aircraft10. A longitudinal axis50is defined along the fuselage18. Each of the tanks41,42,43,44has a configuration corresponding to a volumetric shape and a position in one of the wings31,32. The volumetric shape of a tank refers to the form of the tank such as the size, position, height, width and length of various surfaces that define the tank. The position of a tank refers to the location of the tank in one of the wings31,32of the aircraft10. The configuration of each of the tanks41,42,43,44, i.e. the volumetric shape and position, may vary from one tank to another. The amount of fuel in each of the tanks41,42,43,44and the configuration of each of the tanks41,42,43,44are used to determine the lateral center of gravity of the aircraft10.

In some embodiments, the aircraft10comprises one or more additional tanks for holding fuel. The one or more additional tanks may be positioned in the wings31,32or the fuselage18. By way of a specific and non-limiting example, the aircraft10may comprises a rear fuselage tank. In some embodiments, the amount of fuel in each of the tanks41,42,43,44and the one or more additional tanks and the configuration of each of the tanks41,42,43,44and the one or more additional tanks are used to determine the lateral center of gravity of the aircraft10.

Referring toFIG.1C, each of the tanks41,42,43,44has a corresponding mass of fuel m1, m2, m3, m4. Each mass of fuel m1, m2, m3, m4has a corresponding center of mass c1, c2, c3, c4. The position of each center of mass c1, c2, c3, c4may be represented by a lateral distance from the longitudinal axis50of the aircraft10, substantially centered within the fuselage18. More specifically, a lateral distance d1exemplifies the position of the center of mass c1of the mass of fuel m1of the first tank41, a lateral distance d2exemplifies the position of the center of mass c2of the mass of fuel m2of the second tank42, a lateral distance d3exemplifies the position of the center of mass c3of the mass of fuel m3of the third tank43, a lateral distance d4exemplifies the position of the center of mass c4of the mass of fuel m4of the fourth tank44. In some embodiments, the lateral distances d1, d2, d3, d4and the masses of fuel m1, m2, m3, m4are used to determine the lateral center of gravity of the aircraft10.

With reference toFIG.2, there is illustrated a flowchart of an example method200for providing a lateral center of gravity of an aircraft on an aircraft display, such as the aircraft10ofFIGS.1A,1B and1C. While the method200is described herein with reference to the aircraft10, the method200may be applied to other types of aircraft.

At step202, a fuel distribution in the fuel tanks of the aircraft10is determined. For example, in an embodiment where there are four fuel tanks such as the first tank41, the second tank42, the third tank43and the fourth tank44, the fuel distribution is determined across the fuel tanks41,42,43and44. If more than four fuel tanks are present on aircraft10, the fuel distribution may be determined across all of the fuel tanks in the aircraft10.

The fuel distribution may be determined in various manners depending on practical implementations. For example, determining the fuel distribution may comprise determining each mass of fuel m1, m2, m3, m4and the position of each center of mass c1, c2, c3, c4. If more than four tanks are present, determining the fuel distribution may comprise determining a mass of fuel in each tank and position of a center of mass for each tank. By way of another example, fuel density and fuel volume measurements of tanks41,42,43and44may be used to determine the fuel distribution.

At step206, a lateral center of gravity of the aircraft10is determined based on the fuel distribution. For example, the lateral center of gravity of the aircraft10is determined based on the distribution of fuel in the tanks41,42,43,44of the wings31,32of the aircraft10.

At step208, a signal indicative of the lateral center of gravity is sent to the aircraft display. The signal indicative of the lateral center of gravity may be sent directly to the aircraft display or via another aircraft component. The signal indicative of the lateral center of gravity may be sent via wireless or wired means, depending on the practical implementations of a communication system of the aircraft.

At step210, optionally, the lateral center of gravity is displayed on the aircraft display. The lateral center of gravity may be displayed on the aircraft display in any suitable manner, including via a numerical value, a textual indication, a visual icon or a graphical indicator, an embodiment of which will be described in more detail below. At step211, optionally, a remedial action is triggered when the lateral center of gravity exceeds at least one threshold, as will be explained in more detail below.

With reference toFIG.3A, there is illustrated an example embodiment for determining the fuel distribution, as per step202ofFIG.2, when there are two tanks present on each aircraft wing. At step302, the mass m1in the first tank41is determined, the mass m2in the second tank42is determined, the mass m3in the third tank43is determined and the mass m4in the fourth tank44is determined.

The masses m1, m2, m3, m4may be determined from fuel density and fuel volume measurements of the tanks41,42,43,44. The masses m1, m2, m3, m4may be determined by the product of fuel volume and fuel density and represented by the following equations:
m1=V1p1,  (1)
m2=V2p2,  (2)
m3=V3p3,  (3)
m4=V4p4,  (4)
where V1, V2, V3, V4correspond to fuel volume in the first tank41, the second tank42, the third tank43, and the fourth tank44, respectively, and p1, p2, p3, p4correspond to fuel density in the first tank41, the second tank42, the third tank43and the fourth tank44, respectively.

Fuel density in the tanks may be determined in any suitable manner. For example, fuel density may be measured by a fuel density measuring device comprising one or more sensors for measuring density of fuel. In some embodiments, the fuel density measuring device comprises a hydrometer configured to determine density of a liquid. Other manners for determining fuel density in the tanks are contemplated, including via one or more look-up table(s) or schedule(s), among other possibilities. In some embodiments, an analytical fuel density is used, which may depend on one or more of fuel type, temperature and pressure.

Fuel volume in the tanks may be determined in any suitable manner. For example, fuel volume may be measured by a fuel volume measuring device comprising one or more sensors. In some embodiments, the fuel volume measuring device comprises one or more pressure sensors. In some embodiments, the fuel volume measuring device comprises one or more fuel level sensors. The fuel volume may then be determined depending on the volumetric shape of the tank. One or more of equation(s), look-up table(s), schedule(s) and the like may be used to determine fuel volume from the fuel level and/or the pressure in the fuel tanks. The equation(s), the look-up table(s), and/or the schedule(s) may be predetermined based on the volumetric shape of the tank. Other manners for determining fuel volume are contemplated.

The fuel density and fuel volume determinations may be actively retrieved, or may be passively received. The fuel density and fuel volume determinations of the tanks may be retrieved and/or received from a control system or aircraft computer. In some embodiments, step302comprise triggering determination of the fuel density and/or fuel volume of the tanks whenever method200is initiated.

At step306, the fuel distribution is determined based on the mass of fuel m1in the first tank41, the mass of fuel m2in the second tank42, the mass m3in the third tank43, the mass m4in the fourth tank44and a configuration of the first tank41, the second tank42, the third tank43and the fourth tank44. In some embodiments, determining the first fuel distribution comprises determining the position of the center of mass c1in the first tank41, determining the position of the center of mass c2in the second tank42, determining the position of the center of mass c3in the third tank43and determining the position of the center of mass c4in the fourth tank44. In some embodiments, determining the position of the center of mass c1comprises determining the lateral distance d1between the center of mass c1and the longitudinal axis50. Similarly, in some embodiments, determining the position of the center of mass c2comprises determining the lateral distance d2between the center of mass c2and the longitudinal axis50. In some embodiments, determining the position of the center of mass c3comprises determining the lateral distance d3between the center of mass c3and the longitudinal axis50. In some embodiments, determining the position of the center of mass c4comprises determining the lateral distance d4between the center of mass c4and the longitudinal axis50.

The positions of the center of masses may be determined in any suitable manner. For example, the position of the center of mass in the fuel tank may be determined based on the fuel density and fuel volume of the tank and the configuration of the tank. One or more of equation(s), look-up table(s), schedule(s) and the like may be used to determine the position of the center of mass in the fuel tank from the fuel density and fuel volume measurements of the tank. The equation(s), look-up table(s) and/or schedule(s) may be predetermined based on the configuration of the tank. Other manners for determining the positions of the center of masses are contemplated.

In some embodiments, the lateral distances d1, d2correspond to positive values and the lateral distances d3, d4correspond to negative values. In other words, a positive value for a lateral distance from a center of mass to the substantially centered longitudinal axis50indicates a position on the right side of the aircraft10and a negative value for a lateral distance from a center of mass to the substantially centered longitudinal axis50indicates a position on the left side of the aircraft10.

The lateral center of gravity of the aircraft may be determined based on moment arms of each of the fuel tanks in the aircraft, such as fuel tanks41,42,43,44in the wings31,32. With reference toFIG.3B, there is illustrated an example embodiment for determining the lateral center of gravity of the aircraft10, as per step206ofFIG.2. At step322, a moment arm is determined for each tank41,42,43,44. Each lateral distance d1, d2, d3, d4may be referred to as an “arm”. Each moment arm may be determined from the fuel distribution. A moment for each fuel tank41,42,43,44may be determined by multiplying each mass m1, m2, m3, m4by its corresponding arm d1, d2, d3, d4. At step326, the lateral center of gravity may be determined from the moment arms and a sum of the masses of fuel. The lateral center of gravity may be determined from the sum of the moment arms divided by the sum of the masses of fuel. Accordingly, the determination of the lateral center of gravity CG may be determined on a moment arm basis and may be represented by the following equation:

If more than four tanks are present, the lateral center of gravity CG may be determined in a similar manner based on the fuel masses and center of masses of all tanks in the aircraft.

With reference toFIG.3C, there is illustrated another example embodiment for determining the fuel distribution, as per step202ofFIG.2. At step332, a first fuel distribution between fuel tanks of the first wing31of the aircraft10is determined. At step334, a second fuel distribution between fuel tanks of the second wing32of the aircraft10is determined. For example, in an embodiment where there are two fuel tanks on the first wing31such as the first tank41and the second tank42, the first fuel distribution is determined across fuel tanks41and42. Similarly, for example, in an embodiment where there are two fuel tanks on the second wing32such as the third tank43and the fourth tank44, the second fuel distribution is determined across fuel tanks43and44. If more than two fuel tanks are present on the first wing, the first fuel distribution is determined across all of the fuel tanks on the first wing. Similarly, if more than two fuel tanks are present on the second wing, the second fuel distribution is determined across all of the fuel tanks in the second wing.

With reference toFIG.3D, there is illustrated an example embodiment for determining the first fuel distribution, as per step332ofFIG.3C, when there are two tanks present on an aircraft wing. At step352, the mass m1in the first tank41is determined. At step354, the mass m2in the second tank42is determined. At step356, the first fuel distribution is determined based on the mass of fuel m1in the first tank41, the mass of fuel m2in the second tank42, and a configuration of the first tank41, the second tank42. The first fuel distribution may be determined in various manners depending on practical implementations. For example, determining the first fuel distribution may comprise determining a total mass of fuel in the first wing31and a position of a center of mass of the total mass of fuel in the first wing31. The total mass of fuel in the first wing31and the position of the center of mass of the total mass of fuel in the first wing31may be determined from the masses of fuel m1, m2and the positions of the center of masses c1, c2. In some embodiments, determining the first fuel distribution comprises determining the position of the center of mass c1and the position of the center of mass c2. In some embodiments, determining the position of the center of mass c1comprises determining the lateral distance d1and determining the position of the center of mass c2comprises determining the lateral distance d2. By way of another example, fuel density and fuel volume measurements of the first tank41and the second tank42may be used to determine the total mass of fuel in the first wing31and the position of the center of mass of the total mass of fuel in the first wing31. The second fuel distribution may be determined in various manners depending on practical implementations. The second fuel distribution may be determined in a similar manner as the first fuel distribution or differently therefrom. Note that the number of fuel tanks on the first wing31may differ from the number of fuel tanks on the second wing32.

In some embodiments, determining the second fuel distribution comprises determining the masses of fuel m3, m4, the position of the center of mass c3and the position of the center of mass c4. In some embodiments, determining the position of the center of mass c3comprises determining the lateral distance d3and determining the position of the center of mass c4comprises determining the lateral distance d4.

With reference toFIG.3E, there is illustrated another example embodiment for determining the lateral center of gravity of the aircraft10, as per step206ofFIG.2. At step362, a first center of gravity is determined from the first fuel distribution. The first center of gravity is a center of gravity of the first wing31. In some embodiments, the first center of gravity is determined based on the masses m1, m2and the lateral distances d1, d2. By way of a specific and non-limiting example, equation (6) may be used to determine the first center of gravity CG1. It is noted that the sum of the masses m1, m2is a total mass of fuel in the first wing31.

At step364, a second center of gravity is determined from the second fuel distribution. The second center of gravity may be determined in a similar manner as the first center of gravity, for example based on the masses of fuel m3, m4and the lateral distances d3, d4. The second center of gravity CG2may be represented by the following equation:

It is noted that the sum of the masses of fuel m3, m4is a total mass of fuel in the second wing31.

At step366, the lateral center of gravity is determined from the first center of gravity CG1and the second center of gravity CG2. For example, equation (8) may be used to obtain the lateral center of gravity CG of the aircraft. It is noted that the sum of the masses of fuel m1, m2, m3, m4corresponds to a total fuel mass in the first wing31and the second wing32.

In some embodiments, the fuel distribution may be determined based on fuel volume measurements without fuel density measurements. For example, fuel density may be estimated or approximated for the purposes of determine the masses of fuel m1, m2, m3, m4and the positions of the center of masses c1, c2, c3, c4.

FIG.4Ais a specific and non-limiting example of an aircraft display400for displaying the lateral center of gravity of the aircraft. As illustrated, the aircraft display400comprises a graphical indicator407. The graphical indicator407includes a segment408that extends from a first end401to a second end402. A central marker405is substantially centered between the first end401and the second end402to represent a balanced lateral center of gravity of the aircraft10. A pointer450is displaceable along the segment408between the first end401and the second end402. The pointer450is indicative of a position of the lateral center of gravity of the aircraft10. A position of the pointer450along the segment408is indicative of one of a balanced lateral center of gravity, a left wing imbalance, and a right wing imbalance as a function of a relative position of the pointer450with the central marker405. A right wing imbalance refers to the lateral center of gravity of the aircraft10being offset from the longitudinal axis50towards the right wing31. A left wing imbalance refers to the lateral center of gravity of the aircraft10being offset from the longitudinal axis50towards the left wing32.

Note that while the pointer450is illustrated as a circle, various other shapes may also be used. In addition, the pointer450may be represented by a line, an icon, a letter, a number, or any other graphical element. Its position on the graphical indicator407may also vary. For example, it may be displayed above or below the segment408, instead of overlaid thereon as illustrated. In yet another embodiment, the pointer450is represented by a change in color of a portion of the segment408, as a function of the position of the pointer450. Other embodiments will be readily understood by those skilled in the art.

A left wing imbalance is displayed when the pointer450is between the central marker405and the second end402. A right wing imbalance is displayed when the pointer450is between the central marker405and the first end401. A balanced lateral center of gravity is displayed when the pointer450is aligned with the central marker405. As the pointer450gets closer to the first end401, the right wing imbalance increases. As the pointer450gets closer to the second end402, the left wing imbalance increases. In some embodiments, numerical values may be presented on the graphical indicator407for indicating a degree of lateral center of gravity imbalance.

In some embodiments, a first threshold marker412and a second threshold marker413are provided along the segment408. Each threshold marker412,413is spaced equidistantly from the center marker405towards a respective one of the first end401and the second end402. In some embodiments, the threshold markers412,413correspond to a fuel rebalancing threshold for each aircraft wing. For example, if the pointer450exceeds the first threshold marker412towards the first end401, then this is indicative of a need for rebalancing of fuel between at least some of the fuel tanks in the aircraft due to a right wing imbalance of the lateral center of gravity. Similarly, if the pointer450exceeds the second threshold marker413towards the second end402, then this is indicative of a need for rebalancing of fuel between at least some of the fuel tanks due to a left wing imbalance of the lateral center of gravity. In each case, the direction of imbalance, i.e. a left wing imbalance or a right wing imbalance, will inform the decision on how to rebalance the fuel in order to achieve a balanced later center of gravity for the aircraft. Note that the rebalancing may be performed automatically or manually.

In some embodiments, a third threshold marker414and a fourth threshold marker415are provided along the segment408. The third threshold marker414is spaced from the first threshold marker412towards the first end401. The fourth threshold marker415is spaced from the second threshold marker413towards the second end. The threshold markers414,415may be used to represent another level of imbalance, beyond the need for rebalancing of fuel. For example, the threshold markers414,415may correspond to a crew alert system (CAS) imbalance threshold. When the pointer450exceeds threshold marker414towards the first end401or threshold marker415towards the second end402, this is indicative of a need to alert the crew as the imbalance of the lateral center of gravity has reached a significant level.

With reference toFIG.4B, there is illustrated another embodiment for the aircraft display400. In this example, the graphical indicator407comprises first segment410and second segment420. As illustrated, the first and second segments410,420are positioned one above the other and the pointer450is positioned therebetween. Alternatively, a pointer450may be displayed on each segment410,420, or on an active one of the segments410,420as a function of the status of the aircraft. The first segment410may be used when the aircraft10is in flight and the second segment420may be used when the aircraft10is on the ground. The first segment410extends from the first end401to the second end402and the threshold markers412,413,414,415are associated with the first segment410. The second segment420extends from a third end403to a fourth end404and has threshold markers422,423,424,425associated therewith. Note that threshold markers412,413,414,415may be visually aligned with threshold markers422,423,424,425but segments410,420may use different scales. Alternatively, and as illustrated, the same scale is used for both the first segment410and the second segment420, and the position of each threshold marker is adapted as a function of the appropriate threshold for an inflight imbalance and a ground imbalance, respectively.

One or more of the threshold markers412,413,414,415,422,423,424,425may correspond to remedial action threshold markers. That is, if the pointer450exceeds one of the threshold markers412,413,414,415,422,423,424,425, then this is indicative that a remedial action is occurring or needs to occur. The remedial action may be rebalancing of fuel between at least some of the tanks41,42,43,44, causing an alert indicating that the lateral center of gravity of the aircraft is at dangerous level, and the like.

In some embodiments, a visual element of the graphical indicator407is used to identity one of the two segments410,420as active, as a function of the aircraft status. For example, only one of the two segments410,420may be displayed at any one time. In another example, one of the two segments410,420is illuminated while the other of the two segments410,420is darkened. In yet another example, the active segment is displayed in a first color, such as green, while the inactive segment is displayed in a second color, such as red. Other embodiments for visually indicating the active segment are also contemplated. Note that the aircraft status may be determined using any known means, such as using a weight-off wheels conditions of the aircraft10or an altitude measurement. The aircraft status may be obtained from various aircraft systems, such as an aircraft computer, an engine computer, and the like.

With reference toFIG.4C, there is illustrated another embodiment of the graphical indicator407having two segments410,420. In this example, the first and second segments410,420are positioned side by side. The pointer450is positioned above the active segment. In alternative embodiments, the pointer450is overlaid on the active segment, or a pointer450is provided for each segment410,420, while other visual indicators are used to designate the active segment.

The variants with respect to the pointer450, the nature, position, and size of the threshold markers412,413,414,415,422,423,424,425, and any other elements associated with the graphical indicator407are applicable to any of the embodiments illustrated inFIGS.4A-4C.

With reference toFIG.5A, there is illustrated an example embodiment for displaying the lateral center of gravity on an aircraft display, as per step210ofFIG.2. WhileFIG.5Ais described with reference to the graphical indicator407ofFIG.4B, other embodiments may also apply.

At step502the lateral center of gravity is displayed on the aircraft display400with respect to at least one threshold marker, which may be any one of threshold markers412,413,414,415,422,423,424,425. The lateral center of gravity may be displayed by use of the pointer450. At step504, the pointer450is displaced on the display with respect to the at least one threshold marker when the lateral center of gravity of the aircraft10changes.

In some embodiments, the method200comprises determining the threshold markers as a function of the total fuel mass and displaying the threshold markers on the graphical indicator of the aircraft display. With additional reference toFIG.5B, a graphical representation illustrates various thresholds that vary as a function of the total fuel mass. In particular, a first threshold512, a second threshold514, a third threshold522and a fourth threshold524are illustrated. In this example, the first threshold512corresponds to the first threshold marker412of the first segment410and the second threshold514corresponds to the third threshold marker414of the first segment410. The third threshold522corresponds to the first threshold marker422of the second segment420and the fourth threshold524corresponds to the third threshold marker424of the second segment420. Also in this example, the first and third thresholds512,522are fuel rebalancing thresholds and the second and fourth thresholds514and524are CAS imbalance thresholds.

The total mass of fuel may be used to determine a value for setting a corresponding one of the threshold markers412,414,422,424. For example, a marker550illustrates a value from the third threshold522for a given total fuel mass and the value may be used to set the third threshold marker422of the second segment420.FIG.5Billustrates example thresholds512,514,522,524for use when there is a right wing imbalance. Similar thresholds maybe be used for a left wing imbalance.

As per step211, in some embodiments, the method200comprises triggering a remedial action when the lateral center of gravity exceeds at least one threshold. In some embodiments, step211comprises comparing the lateral center of gravity to at least one of the thresholds512,514,522,524to determine if the lateral center of gravity exceeds at least one threshold. If so, then a remedial action may be triggered.

The remedial action may vary depending on practical implementations. For example, when the lateral center of gravity exceeds the first threshold512or the third threshold522, then a rebalancing of fuel between at least some of the tanks41,42,43,44is triggered. The aircraft10may comprise one or more pumps for transferring fuel between one or more of the tanks41,42,43,44. Each of the tanks41,42,43,44may comprise one or more controllable valves used for transferring fuel to and/or from the tanks41,42,43,44for fuel rebalancing. In another example, when the lateral center of gravity exceeds the second or fourth thresholds522,524, an alert is triggered. The alert may convey that the lateral center of gravity of the aircraft is at a dangerous position. The remedial action may be triggered automatically and performed by one or more control systems of the aircraft. Alternatively, the remedial action may be performed upon input from the pilot or another crew member.

In some embodiments, each of the wings31,32, comprises more than two tanks. For example, each of the wings31,32may comprise three tanks, four tanks, five tanks or more than five tanks. In some embodiments, one or more of the tanks41,42,43,44comprises more than one sub-compartment. Accordingly, the method200may be implemented in a similar manner as described herein but adapted according to the number of fuel tanks and/or sub-compartments.

With reference toFIG.6, the method200may be implemented by a system600comprising a computing device710. In some embodiments, the system600comprises one or more sensors602and/or an aircraft display400. The one or more sensors602may comprise one or more fuel density sensor operatively coupled to computing device710for measuring fuel density in any given tank41,42,43,44of the aircraft10. The one or more sensors602may comprise one or more fuel volume sensors operatively coupled to computing device710for measuring fuel volume in any given tank41,42,43,44of the aircraft10. The one or more sensors602may comprise one or more pressure sensors operatively coupled to computing device710for measuring fuel pressure in any given tank41,42,43,44of the aircraft10. The one or more sensors602may comprise one or more fuel level sensors operatively coupled to computing device710for measuring fuel level in any given tank41,42,43,44of the aircraft10. The one or more sensors602may comprise any other suitable sensors used to measure any suitable parameters relating to the fuel in any given tank41,42,43,44of the aircraft10. In some embodiments, the sensors602are separate from the system600and/or may be existing parts of the aircraft10. In some embodiments, data described herein as coming from the sensors602are provided by one or more other aircraft computing device or control system.

With additional reference toFIG.7, the computing device710comprises a processing unit712and a memory714which has stored therein computer-executable instructions716. The processing unit712may comprise any suitable devices configured to implement the method200such that instructions716, when executed by the computing device710or other programmable apparatus, may cause the functions/acts/steps performed as part of the method200as described herein to be executed. The processing unit712may comprise, for example, any type of general-purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, a central processing unit (CPU), an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof.

The methods and systems for providing a lateral center of gravity of an aircraft described herein may be implemented in a high level procedural or object oriented programming or scripting language, or a combination thereof, to communicate with or assist in the operation of a computer system, for example the computing device710. Alternatively, the methods and systems for providing a lateral center of gravity of an aircraft may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the methods and systems for providing a lateral center of gravity of an aircraft may be stored on a storage media or a device, for example a ROM, a magnetic disk, an optical disc, a flash drive, or any other suitable storage media or device. The program code may be readable by a general or special-purpose programmable computer for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein. Embodiments of the methods and systems for providing a lateral center of gravity of an aircraft may also be considered to be implemented by way of a non-transitory computer-readable storage medium having a computer program stored thereon. The computer program may comprise computer-readable instructions which cause a computer, or more specifically the processing unit712of the computing device710, to operate in a specific and predefined manner to perform the functions described herein, for example those described in the method200. Computer-executable instructions may be in many forms, including program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Typically the functionality of the program modules may be combined or distributed as desired in various embodiments.

The aircraft display400may comprise any kind of display such as an LCD (liquid crystal display), an LED (light emitting diode) display, a CRT (cathode ray tube) display, a HUD (Heads-up Display), a PFD (primary flight display) and/or any other suitable display device. A HUD is any transparent display that presents data in the pilot or co-pilot's field of vision without obstructing the view. A PFD is an aircraft instrument dedicated to flight information. The aircraft display400may display the lateral center of gravity of an aircraft as calculated by the computing device710. Accordingly, the computing device710may cause a GUI (graphical user interface) to display the lateral center of gravity of the aircraft on the aircraft display400. In some embodiments, the aircraft display400is separate from the system600and/or may be an existing part of the aircraft10. The aircraft display400may be operably coupled to the computing device710by one or more data buses such that the computing device710may provide the lateral center of gravity and/or other suitable parameters to the aircraft display400.

Computer simulation, modeling, engineering simulators and/or processing may be used to determine the various equations, look-up tables, and/or schedules described herein. By way of a specific and non-limiting example, computer simulation and modeling is used to determine an equation for each of the tanks41,42,43,44, where each equation is a function of at least one of fuel volume and fuel density and can be used to determine fuel mass and/or a corresponding center of mass. The equations, look-up tables, and/or schedules may be determined in real-time during takeoff, may be pre-determined in advance to takeoff, and/or may be determined at regular intervals.

Computer simulation, modeling, engineering simulators and/or processing may be used to determine the thresholds512,514,522,524that vary as function of total fuel mass. Computer simulation, modeling, engineering simulators and/or processing may be used to determine the thresholds512,514,522,524based on one or more of configurations of the tanks41,42,43,44and a fuel burn sequence. The fuel burn sequence (also known as fuel burn scheduling) corresponds to ordering and amount in which fuel is obtained and burned from the tanks41,42,43,44to keep the longitudinal CG within acceptable limits. The fuel burn sequence may depend on the configuration of tanks41,42,43,44. The thresholds may be determined in real-time during takeoff, may be pre-determined in advance to takeoff, and/or may be determined at regular intervals.