WO2019039945A1

WO2019039945A1 - An aircraft monitoring device and system

Info

Publication number: WO2019039945A1
Application number: PCT/NZ2018/050114
Authority: WO
Inventors: David James George BLACKWELL; Simon John WILLIAMS
Original assignee: Spider Tracks Limited
Priority date: 2017-08-24
Filing date: 2018-08-23
Publication date: 2019-02-28

Abstract

An aircraft monitoring device for providing tracking information as to the position of an aircraft during flight and a system including an aircraft-based monitoring device and a remote monitoring system. The aircraft monitoring system may be truly autonomous determining distress events utilizing information independent of any aircraft avionics systems. Complex evaluation of ADT trigger events may be performed remotely to simplify the aircraft monitoring device. Alternatively, a hybrid solution may be employed in which certain events are triggered by the aircraft monitoring device and some remotely.

Description

AN AIRCRAFT MONITORING DEVICE AND SYSTEM

FIELD

This invention relates to an aircraft monitoring device for providing aircraft condition information and tracking information as to the position of an aircraft, especially during flight, and a system including an aircraft-based monitoring device and a remote monitoring system.

BACKGROUND

Modern commercial aircraft include advanced avionics and communication systems which may be used to provide a wealth of flight data via satellite-based communication systems during normal operation. However, recent incidents, such as flight MH370, have raised concern as to the absence of flight information when the standard systems either are not operational or are circumvented.

This has prompted proposals for externally mounted tamper-proof tracking units that may continue to provide tracking information even if the aircraft's avionic systems fail or they are deliberately disabled. This can be challenging as the electronics must be able to operate in an environmental temperature ranging from +70°C to -70°C, allow GPS signals to be received and tracking information transmitted and not create a fire risk.

Any device that is to be installed in a Transport Category Aircraft needs to be either Type Certified (TC), or Supplementary Type Certified (STC). Any device that connects to other aircraft systems introduces an additional layer of complexity in attaining such certification. Software on board an aircraft may also require compliance with DO-178 coding standards.

The systems proposed to date require specific installation - requiring aircraft manufacturers and regulators to ensure that the additional units comply with all regulatory requirements. Such units typically require a power supply from the aircraft; requiring an additional power supply to be provided and for the aircraft body to be penetrated. Such units typically require integration with the aircraft's data bus and/or flight data control system to assess abnormal aircraft operation and so are not autonomous and require physical integration with other aircraft systems. Such units do not independently monitor aircraft condition information and are not resilient to failure of an aircraft's power supply, communications or navigation systems, thus are not autonomous.

There will also be a requirement in the future to provide autonomous tracking of commercial aircraft when certain distress situations arise. On 2 March 2016, the ICAO Council adopted rules relating to the location of an aircraft in distress. These rules address the Global Aeronautical Distress Safety System (GADSS) autonomous distress tracking (ADT) concept.

ADT requires autonomous operation of a tracking device to provide an enhanced tracking frequency (from the normal 15-minute ATN interval to a 1-minute ADT interval) upon detection of any one of:

1. Unusual attitude;

2. Unusual speed;

3. Imminent terrain collision; or

4. Total loss of thrust

This will require the provision of a large number of such autonomous units in future aircraft as well as a large retrofit market. Designers are currently struggling to design a truly autonomous unit that may be easily fitted to existing and future aircraft.

It is an object of the invention to provide a simple monitoring device that may be easily fitted to existing and future aircraft and an associated system or to at least provide the public with a useful choice.

SUMMARY

According to one example embodiment there is provided an aircraft monitoring device including:

i. a housing adapted for mounting to the exterior of an aircraft containing: a. one or more sensors for sensing aircraft condition information;

b. a device transceiver which periodically transmits aircraft status information; and c. a control system which monitors signals received from the one or more sensors and develops an alert status signal when sensed aircraft condition information is outside permitted aircraft condition values and controls the frequency of transmission of the aircraft status information in dependence on the status of the alert status signal.

According to a further example embodiment there is provided an aircraft monitoring device including:

a. a positioning system providing position information as to the position of the monitoring device in relation to the earth;

b. one or more sensors for sensing aircraft condition information;

c. a device transceiver which, during flight, periodically transmits position information and aircraft attribute information and receives alert signals; and d. a control system which controls the frequency of transmission of the position information and aircraft attribute information in response to an alert signal received by the device transceiver.

According to a further example embodiment there is provided an aircraft monitoring system including:

a. an aircraft monitoring device including:

i. a positioning system providing position information as to the position of the device in relation to the earth;

ii. one or more sensors for determining sensed aircraft condition information independently of any aircraft avionics system;

iii. a device transceiver which, during flight, periodically transmits position information and aircraft condition information and receives alert signals; and

iv. a control system which controls the frequency of transmission of the position information and aircraft condition information in response to an alert signal received by the device transceiver; and

b. a remote monitoring system including: i. a system transceiver for receiving position information and aircraft condition information from the device transceiver,

ii. a database storing:

1. permitted aircraft condition values;

2. terrain information; and

3. flightplan information; and

iii. a decision engine which determines whether aircraft operation is within or outside permitted aircraft attribute values stored in the database based on received position information from the positioning system and signals from the one or more sensors and sends an alert signal to the aircraft monitoring device to increase the frequency of transmission of position information when position or aircraft condition information is outside a permitted range.

a. an aircraft monitoring device including:

iii. a device transceiver which, during flight, periodically transmits position information and aircraft condition information and receives alert signals; and iv. a control system which generates an alert signal if aircraft condition information is outside permitted values and controls the frequency of transmission of the position information and aircraft condition information in response to either an alert signal generated by the control system or an alert signal received by the device transceiver; and

b. a remote monitoring system including:

i. a system transceiver for receiving position information and aircraft condition information from the device transceiver,

ii. a database storing:

1. permitted aircraft condition values; 2. terrain information; and

3. flightplan information; and

iii. a decision engine which determines whether aircraft operation is within or outside permitted values stored in the database based on received position information from the positioning system and aircraft condition information and sends an alert signal to the aircraft monitoring device to increase the frequency of transmission of position and aircraft condition information when aircraft operation is outside permitted values According to a further example embodiment there is provided an aircraft monitoring system including:

a. an aircraft monitoring device including:

ii. one or more sensors for determining sensed aircraft attribute information;

iii. a device transceiver which, during flight, periodically transmits position information and aircraft attribute information and receives alert signals; and

iv. a control system which controls the frequency of transmission of the position information and aircraft attribute information in response to an alert signal received by the device transceiver; and

b. a remote monitoring system including:

i. a system transceiver for receiving position information and aircraft attribute information from the device transceiver, ii. a database storing:

1. permitted aircraft attribute values;

2. terrain information; and

3. flightplan information; and

iii. a decision engine which determines whether aircraft operation is within or outside permitted aircraft attribute values stored in the database based on received position information from the positioning system and signals from the one or more sensors and sends an alert signal to the aircraft monitoring device to increase the frequency of transmission of position information when an attribute is outside a permitted aircraft attribute value.

i. a positioning system providing position information as to the position of the monitoring device in relation to the earth;

ii. one or more sensors for sensing aircraft attribute information;

iii. a device transceiver which, during flight, periodically transmits position information and aircraft attribute information and receives alert signals; and iv. a control system which controls the frequency of transmission of the position information and aircraft attribute information in response to an alert signal received by the device transceiver.

a. an aircraft monitoring device including:

ii. a device transceiver which, during flight, periodically transmits position information and receives alert signals; and

iii. a control system which controls the frequency of transmission of the position information in response to an alert signal received by the device transceiver; and

b. a remote monitoring system including:

i. a system transceiver for receiving position information from the device transceiver,

ii. a database storing:

1. permitted aircraft attribute values;

2. terrain information; and 3. flightplan information; and

iii. a decision engine which determines whether aircraft operation is within or outside permitted aircraft attribute values stored in the database based on received position information from the positioning system and sends an alert signal to the aircraft monitoring device to increase the frequency of transmission of position information when an attribute is outside a permitted aircraft attribute value.

It is acknowledged that the terms "comprise", "comprises" and "comprising" may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, these terms are intended to have an inclusive meaning - i.e., they will be taken to mean an inclusion of the listed components which the use directly references, and possibly also of other non-specified components or elements. Reference to any document in this specification does not constitute an admission that it is prior art, validly combinable with other documents or that it forms part of the common general knowledge.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings which are incorporated in and constitute part of the specification, illustrate embodiments of the invention and, together with the general description of the invention given above, and the detailed description of embodiments given below, serve to explain the principles of the invention, in which:

Figure 1 shows an aircraft monitoring device according to one embodiment mounted within an aircraft navigation light cavity; Figure 2 shows an aircraft monitoring device according to another embodiment mounted within an aircraft navigation light cavity;

Figure 3 shows a schematic electrical diagram of the aircraft monitoring device shown in Figure 1; Figure 4 shows diagrammatically a processing engine of the aircraft monitoring device shown in Figure 3; and

Figure 5 shows a schematic electrical diagram of an aircraft monitoring device according to another embodiment.

DETAILED DESCRIPTION

The following description describes a number of solutions providing a simple autonomous aircraft monitoring system and a remote monitoring and analysis system (typically ground based) and hybrid solutions. Different solutions utilize different power sources and require different information sources.

Figure 1 illustrates an aircraft monitoring device 5 within a housing according to one example embodiment located within a navigation light cavity 1 of an aircraft wingtip 2. Whilst a navigation light cavity is referred to in this embodiment it will be appreciated that there are numerous other locations where an aircraft monitoring device may be mounted on the outside of an aircraft such as an emergency locator transmitter housing, GPS housing, antenna housings etc. Navigation lights of an aircraft are in continuous operation during flight and so could provide a power supply to an aircraft monitoring device without requiring a separate power supply.

Navigations lights 7 normally connect to a navigation light power supply connector 3. In some cases, the lights will connect directly via screw, bayonet or plug fittings whilst in others a connector may plug into the navigation light power supply connector 3 and supply the navigations via a power supply cable. In this example aircraft monitoring device 5 includes a power connector 4 that plugs into navigation light power supply connector 3 to supply power to aircraft monitoring device 5. Aircraft monitoring device 5 includes an output power supply line and power connector 6 to provide power to navigation lights 7. These may be the pre-existing navigation lights or LED replacements.

The small form factor of the aircraft monitoring device 5 to be fitted into spare space within the navigation light cavity. The navigation lights 7 will preferably be replaced with LED lights so that the power demand of the LED navigation lights and aircraft monitoring device is less than the power requirement of conventional navigation lights. The power supply will be managed so as to not affect operation of the navigation lights as will be discussed below.

Figure 2 shows another example embodiment in which the aircraft monitoring device 9 incorporates navigation lights 10 as a complete unit to replace conventional navigation lights. The navigation lights 10 are preferably LED lights secured to the housing of aircraft monitoring device 9. A power connector 8 supplies power from navigation light power supply connector 3 to supply power to aircraft monitoring device 9 via a power cable. However, the unit may be designed with a power connector secured to the housing of aircraft monitoring device 9 to plug directly into navigation light power supply connector

3.

In both examples the aircraft monitoring device may be designed so that power is supplied from power supply connector 3 directly to the navigation lights with the power take off to the aircraft monitoring device being designed to maintain supply to the navigation lights in the event of failure. The power supplied to components other than the LED lights may be limited by a power regulator to a level less than the rated power supplied to the connector less the rated power demand of the LED light. Further the supply to the aircraft monitoring device may be fused in case of power regulator failure.

Figure 3 shows a schematic diagram of the components of aircraft monitoring device 5 shown in Figure 1. The main controller 11 may be a suitable microcomputer with associated support circuitry. Controller 11 may include a local transceiver 12 for short range F communication from the aircraft to the controller using Wi-Fi, Bluetooth or a similar short range communication protocol. Transmitter 13 may be a non-terrestrial communications system such as a satellite system or a system positioned between ground and low earth orbit, such as a balloon-based system (such as Google's project Loon) or aircraft-based systems (such as long flight duration solar powered communication aircraft). Where satellite communications are employed transmitter 13 may be a satellite transmitter suitable for periodically transmitting position information to a ground-based monitoring station via satellite 27, such as the Iridium satellite system. Receiver 14 may be a satellite receiver suitable for receiving information and commands from a ground- based monitoring station via satellite 27, such as the Iridium satellite system (or it may employ other non-terrestrial communication channels). Positioning system 15 may be a GPS, GLONASS, Beidou, Galileo or other positioning system which periodically determines aircraft position based on signals received from multiple GPS satellites 28.

Power connector 20 is designed to connect to navigation light power supply connector 3 (Figure 1) to supply power to controller 11 and a parallel power connection supplies power to connector 19 to drive navigation lights. Similar connections may be employed if other cavities are used. A backup battery 17 is provided in case there is any discontinuity of power supply. In a typical application the backup battery may be sized to provide at least 30 hours back up power supply. The controller 11 maintains the backup battery charged when power is available from connector 20 or additionally a solar cell 16 may be provided to charge the battery when there is sufficient light. Alternatively, the monitoring device may be powered only by the battery to be entirely independent of the aircraft power supply.

The aircraft monitoring device may also include sensors for measuring aircraft condition information such as an inertial measurement unit (IM U) 23 including gyroscopes and accelerometers to determine orientation and rates of change of orientation. It will be appreciated that accelerometers and/or gyroscopes and/or magnetometers may be provided individually or in combination instead of being provided within an IMU. A temperature sensor 22 may provide the controller 11 information as to the temperature within the navigation light cavity so that the temperature of the electronic components may be maintained in a desired range. The controller may drive electronics of the controller 11 (such as oscillators) or a resistive load 21 to heat the cavity. To avoid excess temperatures electronic components may be driven in such a manner as to reduce their heat output. An altimeter 40 may be provided to independently provided altitude information, preferably based on static pressure within the housing containing the aircraft monitoring device. For this reason, the housing may be designed to permit sufficient airflow into the housing to allow static pressure to be measured sufficiently accurately. A camera 18 may also be provided, if desired, to provide images of the aircraft or its environment to provide additional information for ground-based monitoring. A remote 25 may also be provided to allow cabin crew to communicate an alert condition on board the aircraft. This may communicate wirelessly via local transceiver 12 or it could communicate over wires. The alert may be due to a hijacking or an aircraft malfunction, such as complete loss of electrical power. One or more button 25b may be provided to send an alert signal to controller 11 and a display 25a may display an alert status.

Additionally, a remote sensor 26 may be provided. This may also communicate wirelessly via local transceiver 12 or it could communicate over wires. The sensor may be one or more of a pressure sensor, a temperature sensor, a microphone, a camera, a chemical sensor or a radiation detector. The wireless sensor may send an alert signal to controller 11 upon detection of an abnormal event such as: abnormal pressure (cabin pressure above or below a prescribed range), abnormal temperature (temperature above or below a prescribed range), sound (loss of thrust due to absence of characteristic engine noise, explosion or interpreted words matching an exception list), image (flash consistent with explosion, facial identification or interpreted behavior of passengers), substance (e.g. smoke or explosive) etc. is detected within the cabin or it may simply send sensed information and controller 11 may determine if a distress condition exists. These devices may be battery powered so as to operate even if aircraft power is not available. Once controller 11 determines that an alert condition exists the aircraft monitoring device may increase its frequency of provision of position data to ground monitors and may additionally provide additional information as to the nature of the alert and other sensed information. Once such an alert is triggered the aircraft monitoring device may be configured to only move from its alert state if it receives a command to do so from the ground via satellite receiver 14 or it may be configured to allow deactivation in another way. Control circuit 11 may also have access to a local database 24 that may store information such as a global terrain database, flightplan information and a database of permitted aircraft condition values (a value outside these ranges giving rise to a distress alert), "aircraft condition values" is a subset of aircraft attribute values and includes aircraft orientation and operational attributes of the aircraft including thrust, aircraft performance and environmental information including cabin pressure, temperature, sound and vibrations but does not include positional information or power supply to an aircraft monitoring device or information from aircraft avionics systems (i.e. attributes of an aircraft, other than its position, that may be determined independently of any aircraft systems). An ADT alert may be triggered by:

1. unusual attitude - excessive roll, pitch or yaw or rate of change based on GPS data, flightplan and terrain map); 2. unusual speed - vertical speed, stall speed, low airspeed or overspeed - based on

GPS data, flightplan and "usual speed range" values for types of flight);

3. terrain collision - inappropriate altitude or rate of closure - compare GPS information to earth surface model and flightplan); and

4. complete loss of thrust (by analysis of speed and flight path). Aircraft operators may have additional operator defined triggers over and above any required ADT triggers such as rules as to airspeed at certain altitudes, rate of descent etc.

The controller 11 can produce distress alerts based purely on GPS position information and terrain and flightplan information (where a special three antenna configuration is employed). Alternatively distress alerts may be generated purely on aircraft condition information from an IMU, accelerometers, gyroscopes, magnetometers, an altimeter, remote 25 or remote sensor 26. Signals from the IMU may be used independently or in addition to GPS position information to evaluate some distress triggers. It is advantageous to utilize an IMU, accelerometer or gyroscope to determine pitch, roll and yaw as this is simple, inexpensive and accurate. Some rules will be context dependent (e.g. allowed flight attributes during takeoff and landing) and controller 11 will determine the context based on GPS data, the flightplan and terrain.

Figure 4 shows diagrammatically processing engines within controller 11 which determine whether aircraft operation is within or outside permitted aircraft attribute values based on position information from the positioning system 35 and database 36 (which may be a component of database 24 shown in Figure 3) and controls the frequency of transmission of position information from the transmitter 13 based on whether operation is within or outside permitted aircraft attribute values.

Speed decision engine 30 determines the presence of an ADT alert condition based on position information received from the GPS positioning system 35 and if this exceeds a permitted value stored in database 36 it supplies an alert signal to OR gate 34. The context may be determined by evaluating the flightplan and position information and applying speed attribute values applicable to the context. OR gate 30 may be implemented in software and is simply illustrated as an OR gate for explanation. OR gate 34 generates a ADT alert if any decision engine produces an alert and an OR gate alert causes controller 11 to increase the frequency of transmission of position information.

Decision engine 31 determines aircraft attitude based on position information received from the GPS positioning system 35 and supplies an alert signal to OR gate 34 if aircraft attitude is outside permitted values stored in database 36. Again, these may be context dependent values.

Decision engine 32 determines a terrain collision alert based on position information from GPS positioning system 35 and flightplan and terrain information and permitted attribute values stored in database 36.

The loss of thrust decision engine 33 determines loss of thrust based on evaluation of position information received from the positioning system 35 (e.g. inferred from rate of decent and speed) and if outside a permitted value stored in database 36 supplies an alert signal to OR gate 34. IMU 23 may also be used to determine loss of thrust by detecting the absence of any vibration characteristic of at least one engine operating.

If OR gate 34 generates an alert controller 11 increases the frequency of transmission of position information from the transmitter 13 (to at least one transmission per minute).

Other situations that may give rise to an alert include:

1. Detection of aircraft condition information outside of a permitted range;

2. Activation of remote 25 by a crew member,

3. Detection of a cabin condition outside an allowed range by remote sensor 26, or

4. Loss of power - e.g. from navigation light power connector 3 (crew may deliberately turn off the navigation lights to generate an alert or a loss of power may trigger an alert). Referring now to Figure 5 an aircraft monitoring device according to a further embodiment is shown. Like integers to those shown in Figure 3 are given like numerals and descriptions of those integers are given above. In this embodiment some of the information previously stored in database 24 may be stored within a remote monitoring system 37, typically being a ground-based server (although it could possibly be provisioned on a satellite etc.) connected via a transceiver to the satellite communication system 27. Remote monitoring system 37 may store information relating to terrain information and flightplan information etc. so that it may perform intensive processing operations to relieve some of the processing from controller 11. Depending upon the application it may also store aircraft condition information and receive aircraft condition information to assess whether there is a distress event. This configuration has the advantage that the monitoring device may be simplified with the processing of at least some distress conditions being performed remotely. This may require only a single instance of the database to be maintained by a remote monitoring system and complex processing to be performed by the remote ground-based monitoring system rather than the air-based monitoring device. This solution allows autonomous operation and may provide compliance with ADT requirements without connection to aircraft information systems using a simple monitoring device.

In this case power may be obtained from a suitable aircraft power supply 38 when power is available. As in the embodiment shown in Figure 3, power may be provided by a backup battery should power not be available from aircraft power supply 38. In some situations battery only operation may be used without the need for even power supply 38. This embodiment is primarily focused on providing a simple system meeting ADT requirements. Whilst it may be mounted in the navigation lights as per the embodiment shown in Figure 3 it may be mounted elsewhere in the aircraft - the focus of the ADT requirements is on autonomous operation (i.e. independent of aircraft systems) to provide increased reporting of position information upon the occurrence of an ADT event. Depending upon where the monitoring unit is mounted it may be necessary to provide an externally mounted antenna connected to the monitoring device. In one embodiment, during normal operation, flight data (position information from GPS unit 15 and orientation information from IMU 23) is periodically transmitted via transmitter 13 and satellite 27 to ground based server 37. Ground based server 37 analyses this information with permitted aircraft attribute values, terrain information and flightplan information stored in its database. The ground-based server performs the processing of flight data to determine whether a distress trigger condition has been satisfied. This processing may be based on information in the following ways: i. Unusual attitude - either

a. IMU - use information from onboard IMU to determine excessive roll, pitch or yaw or rates of change thereof

b. GPS - using three orthogonal antennas in a triad formation roll, pitch and yaw and rates of change thereof can be determined using a system provided by Novatel.

c. IMU and GPS -the above two techniques may be combined for greater accuracy.

ii. Unusual speed - vertical speed, stall speed, low airspeed or overspeed - either a. GPS - sequential GPS information may be analysed to provide speed information based on the time and distance between readings b. IM U and GPS combined

iii. Collision with terrain - inappropriate altitude or rate of closure:

a. GPS - position and time information may be referenced with terrain data and the flightplan to determine if a terrain collision threshold has been breached.

b. Altimeter - received altimeter information

iv. Total loss of thrust - either:

a. IMU - detects all engines not running due to complete absence of characteristic engine vibrations.

b. GPS - by analysing pitch and speed etc.

c. IMU and GPS - utilize both techniques for enhanced accuracy.

The attribute values used in the above processing may be context dependent. For example, different attribute values may be applicable for different altitudes or portions of a flightplan etc. It will be appreciated that as all four ADT triggers may be determined by GPS data only that an IMU is not strictly required where GPS data is available - although an IM U is a relatively inexpensive component and its inclusion is preferred to provide a simple, accurate and cost effective solution.

As the processing is performed on the ground complex algorithms may be employed to determine ADT triggers whilst the air-based monitoring device may simply relay information.

A hybrid system is also possible where simple triggers may be determined by the air-based monitoring system (e.g. alert received from remote 25 or remote sensor 26, attitude, pitch or roll values from IMU exceed threshold, altitude or change in altitude outside permitted range, complete loss of power detected by IMU, speed outside of permitted range etc.) with complex evaluation performed by the ground-based system (e.g. ground collision etc.). In this case database 24 simply contains permitted aircraft condition values to enable local determination of triggers based on aircraft condition information. Such a hybrid solution enables rapid local response whilst allowing a relatively simple aircraft monitoring device to be employed.

Where a distress trigger is satisfied an alert signal is transmitted from ground-based server 37 to air-based monitoring device via satellite network 27. Upon receipt of a distress signal the monitoring device switches from a normal mode to a distress mode and increases the frequency of its transmission of position information (typically to at least once per minute). Whilst the system is operating in a distress mode (e.g. ADT trigger satisfied) position and/or other information can be pushed to a third-party distress tracking repository so that data may be captured in a central repository (API) to be preserved for subsequent analysis. Additionally, an authorized user of the monitoring system may manually activate the forwarding of position and/or other information to a third-party distress tracking repository when the system is not in a distress mode.

In the case of false alarm, or recovery from a distress phase, the ADT may be de-activated if certain conditions are satisfied. In one mode of operation deactivation can only be done by "the activating mechanism". This may mean that a condition that was triggered from an onboard sensor can only be deactivated from the flight deck (optionally only iff that particular parameter is now back within limits) or if triggered from the ground (either manually or automatically) it can only be deactivated by a ground operator (optionally iff that particular parameter is now back within limits).

When either wireless alert remote 25 or wireless sensor activated alert 26 triggers an alert then ADT alert status may either be deactivated by the activating device or may be deactivated from the ground depending on user configuration.

The aircraft monitoring system may also detect "abnormal operation" not satisfying an ADT trigger, such as a loss of communication between the ground server 37 and aircraft monitoring device or an operator specified condition short of an ADT trigger (e.g. operator rules as to speed at certain altitudes). In this situation the system may generate an alert to flight operations so that the flight may be closely monitored and, if appropriate, communication with the aircraft attempted. This may lead to ground-based triggering of an ADT alert if the abnormal operation is not resolved. The aircraft monitoring unit may also itself trigger an ADT condition in the absence of communication with the ground- based server 37 for a prescribed period.

There is thus provided a truly autonomous system for determining an ADT alert condition using a simple monitoring device and without requiring any connection to aircraft avionic systems. Complex analysis of flight data is performed remotely, simplifying the software required for the monitoring device. On board triggering by crew or on-board sensors is also provided.

There is an option to simply retrofit the monitoring device into a navigation light socket or other available cavity for its power supply due to its small form factor. This provides a tamperproof location that can't be accessed in flight, is suited for satellite communication and has a convenient power supply. The system is able to use an aircraft's power supply during normal operation but reverts to an independent power supply (battery) upon transition to an ADT mode of operation.

While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of the Applicant's general inventive concept.

Claims

CLAIMS:

An aircraft monitoring device including: i. a housing adapted for mounting to the exterior of an aircraft

containing: a. one or more sensors for sensing aircraft condition information; b. a device transceiver which periodically transmits aircraft status information; and c. a control system which monitors signals received from the one or more sensors and develops an alert status signal when sensed aircraft condition information is outside permitted aircraft condition values and controls the frequency of transmission of the aircraft status information in dependence on the status of the alert status signal.

An aircraft monitoring device as claimed in claim 1 wherein the one or more sensors include a plurality of accelerometers.

An aircraft monitoring device as claimed in claim 1 wherein the one or more sensors include a plurality of gyroscopes.

4. An aircraft monitoring device as claimed in claim 1 wherein the one or more sensors include an inertial measurement unit (IM U).

5. An aircraft monitoring device as claimed in any one of claims 2 to 4 wherein the control system determines loss of thrust when signals received from the one or more sensors indicate the absence of characteristic vibrations generated by an aircraft engine.

6. An aircraft monitoring device as claimed in any one of claims 2 to 5 wherein the control system determines roll, pitch or yaw values based on signals received from the gyroscopes, accelerometers or IM U and generates an alert signal when a roll, pitch or yaw value is outside a permitted range.

7. An aircraft monitoring device as claimed in anyone of the preceding claims including a magnetic compass which generates an alert when the aircraft heading is outside permitted profile values.

8. An aircraft monitoring device as claimed in any one of the preceding claims wherein the one or more sensors include an altimeter and the control system generates an alert signal when an altimeter value is outside a permitted range.

9. An aircraft monitoring system as claimed in claim 8 wherein the altimeter is an air pressure-based altimeter.

10. An aircraft monitoring device as claimed in any one of the preceding claims wherein the one or more sensors include one or more camera mounted to capture images of the exterior of an aircraft.

11. An aircraft monitoring device as claimed in any one of the preceding claims including a positioning system for monitoring aircraft position.

12. An aircraft monitoring device as claimed in claim 11 wherein the control system includes a database of permitted position information and determines whether aircraft operation is within or outside permitted values based on position information received from the positioning system and controls the frequency of transmission of position information from the transmitter based on whether the aircraft position is within or outside permitted aircraft position values.

13. An aircraft monitoring device as claimed in claim 11 wherein the control system includes a database of permitted derived position information and derives information from aircraft position information and determines whether aircraft operation is within or outside permitted derived position values based on derived position information and controls the frequency of transmission of position information from the transmitter based on whether derived position information is within or outside permitted values.

14. An aircraft monitoring device as claimed in claim 13 wherein the derived position information is speed, heading, or a rate of change.

15. An aircraft monitoring device as claimed in any one of the preceding claims wherein the device transceiver communicates via non-terrestrial communications.

16. An aircraft monitoring device as claimed in claim 15 wherein the device transceiver communicates devices located between ground and low earth orbit.

17. An aircraft monitoring device as claimed in any one of the preceding claims including a remote actuator for use within an aircraft cabin which transmits an alert signal to the aircraft monitoring device when activated.

18. An aircraft monitoring device as claimed in claim 17 wherein the remote actuator communicates wirelessly.

19. An aircraft monitoring device as claimed in claim 17 or claim 18 wherein the remote actuator includes a pressure sensor and transmits an alert signal when the pressure within an aircraft is outside a permitted range.

20. An aircraft monitoring device as claimed in claim 17 or claim 18 wherein the remote actuator includes a temperature sensor and transmits an alert signal when the temperature within the aircraft is outside a permitted range.

21. An aircraft monitoring device as claimed in claim 17 or claim 18 wherein the remote actuator includes a microphone and transmits an alert signal when the when a sound of a prescribed profile is detected.

22. An aircraft monitoring device as claimed in claim 21 wherein the remote actuator generates an alert signal when a specific word or words are identified.

23. An aircraft monitoring device as claimed in claim 17 or claim 18 wherein the remote actuator includes a camera and generates an alert signal when one or more images satisfies prescribed criteria.

24. An aircraft monitoring device as claimed in any one of the preceding claims including a battery for powering the aircraft monitoring device.

25. An aircraft monitoring device as claimed in claim 24 including a solar cell configured to charge the battery.

26. An aircraft monitoring device as claimed in any one of the preceding claims wherein the control system monitors signals received by the device transceiver for a remote alert signal and controls the frequency of transmission of the aircraft status information in dependence on the status of the remote alert signal.

27. An aircraft monitoring device including: a. a positioning system providing position information as to the position of the monitoring device in relation to the earth; b. one or more sensors for sensing aircraft condition information; c. a device transceiver which, during flight, periodically transmits position information and aircraft attribute information and receives alert signals; and d. a control system which controls the frequency of transmission of the position information and aircraft attribute information in response to an alert signal received by the device transceiver.

28. An aircraft monitoring device as claimed in claim 27 wherein the control system monitors the aircraft condition information and generates an alert signal if aircraft condition information is outside of permitted values.

29. An aircraft monitoring system including:

a. an aircraft monitoring device including:

i. a positioning system providing position information as to the position of the device in relation to the earth; ii. one or more sensors for determining sensed aircraft condition information independently of any aircraft avionics system; iii. a device transceiver which, during flight, periodically transmits position information and aircraft condition information and receives alert signals; and

a remote monitoring system including:

i. a system transceiver for receiving position information and aircraft condition information from the device transceiver, ii. a database storing:

1. permitted aircraft condition values;

2. terrain information; and

3. flightplan information; and

30. An aircraft monitoring system as claimed in claim 29 wherein the control system controls the frequency of transmission of the position information and aircraft condition information based on its own analysis of the position information and aircraft condition information.

31. An aircraft monitoring system as claimed in claim 29 or claim 30 wherein the aircraft monitoring device is adapted to be mounted to the exterior of an aircraft independent of aircraft avionics systems. 32. An aircraft monitoring system including:

a. an aircraft monitoring device including:

iv. a control system which generates an alert signal if aircraft condition information is outside permitted values and controls the frequency of transmission of the position information and aircraft condition information in response to either an alert signal generated by the control system or an alert signal received by the device transceiver; and

b. a remote monitoring system including:

1. permitted aircraft condition values;

2. terrain information; and

3. flightplan information; and iii. a decision engine which determines whether aircraft operation is within or outside permitted values stored in the database based on received position information from the positioning system and aircraft condition information and sends an alert signal to the aircraft monitoring device to increase the frequency of transmission of position and aircraft condition information when aircraft operation is outside permitted values.

According to a further example embodiment there is provided an aircraft monitoring system including: a. an aircraft monitoring device including:

i. a positioning system providing position information as to the position of the device in relation to the earth; ii. one or more sensors for determining sensed aircraft attribute information;

b. a remote monitoring system including:

1. permitted aircraft attribute values;

2. terrain information; and

3. flightplan information; and

34. An aircraft monitoring device including:

ii. one or more sensors for sensing aircraft attribute information; iii. a device transceiver which, during flight, periodically transmits position information and aircraft attribute information and receives alert signals; and

iv. a control system which controls the frequency of transmission of the position information and aircraft attribute information in response to an alert signal received by the device transceiver.

35. An aircraft monitoring system including:

a. an aircraft monitoring device including:

i. a positioning system providing position information as to the position of the device in relation to the earth; ii. a device transceiver which, during flight, periodically transmits position information and receives alert signals; and

b. a remote monitoring system including:

ii. a database storing:

1. permitted aircraft attribute values;

2. terrain information; and

3. flightplan information; and

iii. a decision engine which determines whether aircraft operation is within or outside permitted aircraft attribute values stored in the database based on received position information from the 5 positioning system and sends an alert signal to the aircraft monitoring device to increase the frequency of transmission of position information when an attribute is outside a permitted aircraft attribute value.

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