EP1456725A1

EP1456725A1 - Method and device for detecting the takeoff and landing times of a flying device

Info

Publication number: EP1456725A1
Application number: EP02791685A
Authority: EP
Inventors: Volker Peters
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-12-17
Filing date: 2002-11-16
Publication date: 2004-09-15
Also published as: AU2002358017A1; DE10161879A1; DE10161879B4; WO2003052534A1

Abstract

Disclosed is a method for detecting the takeoff time and/or landing time of a flying device on the basis of air pressure measurement. The air pressure at the flying device is continuously measured before, during, and after takeoff or landing, and the changes of air pressure over time are recorded. A takeoff or landing can be detected on the basis of predefined criteria that are specific to each flying device. The takeoff or landing time is established on the basis of the measured changes of air pressure over time once a takeoff or landing has been detected. The method is carried out by a device detecting takeoff times and/or landing times. Said device comprises a pressure sensor 2 for measuring air pressure, a first memory for recording the measured changes of air pressure over time, and a second memory containing criteria specific to each flying device for recognizing takeoffs or landings. Said device also comprises a microprocessor 1 processing the measured air pressure data and comparing said data with the criteria stored in the memory.

Description

Method and device for determining the takeoff and landing times of an aircraft

description

The invention relates to a method for determining the takeoff and / or landing times of an aircraft. The invention also relates to a corresponding device.

In general aviation, the take-off and landing times of an aircraft must be recorded to the minute. On the one hand, these times are used to control when an aircraft took off or landed, on the other hand, the operating hours of an aircraft are calculated from these times. The maintenance intervals of an aircraft are determined depending on the number of operating hours and the number of take-offs and landings. The greater the number of operating hours and the number of take-offs and landings, the more and more intensive maintenance has to be carried out. The takeoff and landing times are therefore recorded in a maintenance book along with other values.

In sport aviation in particular, pilots must keep a personal log book. The start and landing times recorded. In addition, the aircraft type, the locations of take-offs and landings, the flight duration and other events are recorded in the logbook. The total flight time is calculated from the take-off and landing times of the personal flight log. On the basis of the entries in the personal flight log, the pilot demonstrates the legally prescribed minimum flight times within a specified time interval. Proof of the minimum flight time is required by the pilot in order to have his flight license, which is always only issued for a limited period, extended.

It is precisely defined what time is considered the take-off or landing time. The take-off time is the time in which the aircraft takes off with its landing gear from the runway for the first time and is no longer in contact with the ground. The landing time is the time at which the aircraft's landing gear touches the ground or the runway for the first time. Both take-off and landing times are registered to the minute.

The take-off and landing phases are the most labor-intensive phases during a flight. Both phases require the full concentration and the full attention of the pilot in command. The stipulated determination of take-off and landing times is an additional burden for the pilot and, from his point of view, a rather annoying obligation. For this reason, take-off and landing times are often recorded rather imprecisely and only with estimates. The determination of the times is often forgotten due to the high workload during takeoff or landing. Then it is necessary to inquire about the times at the responsible air traffic control point. The resulting additional radio communication is annoying and annoying.

In order to relieve the pilot of the burden when determining the takeoff and landing times, devices are known which automatically record the takeoff and landing times. These known recording devices are based on the principle of dynamic pressure measurement and determine the exact takeoff and landing time using further data measured on the aircraft. They are integrated into the aircraft through fixed installation. As a component of the aircraft, they are subject to legal approval. Official approval makes such built-in detection devices expensive. A further increase in the price of these recording devices follows from the installation, which also requires acceptance. Another disadvantage of the previously known devices is that they can only be used by the pilot who is currently using the aircraft in which the device is installed. The device therefore only uses the aircraft personally if it always flies the same aircraft in which such a recording device is installed. However, most hobby pilots do not have their own aircraft and alternately fly with different aircraft. As a result, they can only benefit from the automatic recording of take-off and landing times in individual cases.

Even if a hobby pilot has his own aircraft, he often shy away from the high costs of a permanently installed registration device, which are made up of the investment costs and the running costs for regular maintenance and inspections.

The present invention is therefore based on the technical problem of determining the takeoff or landing time independently of the aircraft used, that is to say without having to resort to measured values and data which are made available by other aircraft components.

The present invention is based on the consideration that the air pressure on the aircraft fluctuates as a function of the flight altitude, and that the desired times for takeoff and landing can thus be determined from the time course of the air pressure. The air pressure can be determined relatively easily and in particular independently of the technical equipment of the aircraft, as a result of which the desired independence from the aircraft currently being used is achieved.

The object aimed at specifying a method is achieved by the method steps specified in claim 1.

According to the invention, the air pressure on the aircraft is continuously measured before, during and after take-off or landing. The determined measured values of the air pressure are recorded as a time course. On the basis of predetermined criteria specific to the aircraft type, a takeoff or a landing can be reliably recognized from the recorded course of the air pressure. After a take-off or a landing has been recognized, the permanent the takeoff or landing time is determined over time.

The great advantage of the method according to the invention is that only one physical quantity, namely the air pressure, has to be measured to determine the takeoff or landing time. The ambient pressure is determined as the air pressure, which prevails on the outside of the aircraft or in the interior or cabin of the aircraft. No aircraft-specific data therefore need to be evaluated, so that the method can be used independently of a specific aircraft.

Typically, the take-off of an aircraft is characterized by the fact that a certain rate of climb is exceeded for a certain time. For the physical size of the air pressure, this means that the air pressure must change quickly enough when there is a start. A start can thus be recognized in that the speed at which the air pressure changes exceeds a predetermined threshold value for a certain period of time.

After recognizing a successful start, the start time can be determined afterwards. The starting point is the point in time at which the speed of the change in air pressure exceeds the predetermined threshold value, which was used as a criterion for recognizing a start, for the first time. This means that the take-off time is the time at which the climb speed of an aircraft reaches a certain value for the first time. Since the start time only has to be recorded to the minute, this simple condition is sufficient.

The detection of a landing can be linked to the fulfillment of the following three criteria. First, the rate of change in air pressure must exceed a predetermined limit, and the difference in air pressure itself must exceed a certain value. Thereafter, the speed at which the air pressure changes must not fall below this limit value for longer than a predetermined period of time. As a third criterion, the air pressure must be essentially constant for a predetermined period of time and may only fluctuate within predetermined narrow limits. In order to determine whether the air pressure is constant, it proves advantageous to determine the deviation of the Air pressure from its mean as a measure. In this way, the limits within which the air pressure may fluctuate can be specified without the knowledge of the absolute air pressure being necessary.

The three conditions for recognizing a landing reflect a typical descent, the subsequent interception phase and the subsequent roll-out on the runway after the landing.

The time at which the speed of the change in air pressure falls below the limit value from the conditions for the landing is used to determine the landing time. The landing time is determined retrospectively, i.e. when the aircraft has already landed, from the course of the measured air pressure.

The takeoff and landing times are preferably stored. This means that these two times are still available at a later point in time, for example after the flight has been completed. They can be called up by the pilot and transferred to his personal logbook.

It is advantageous for the user if the take-off time or landing time is shown on a display. The user can then read the determined times from the display provided for this purpose and take note of them.

It also proves to be advantageous to output the determined takeoff time, the landing time and / or further values relating to the aircraft as digitized data via an interface. The determined times can thus be transferred to other devices, for example a PC, and used there for further processing or archived for long-term storage.

In a preferred development of the method according to the invention, a landing attempt with subsequent take-off (touch and go) can also be recognized if the air pressure exceeds a first value and then falls below a predetermined second value, the first value of the air pressure being greater than the second value , Recognizing such a landing attempt is important for the training of flight students. These are supposed to _ _

practice taking off and landing often. For normal landing, however, the roll-out phase on the runway is missing. Instead, the aircraft takes off immediately after touchdown and then quickly gains altitude. Conditions for recognizing such a landing attempt must therefore be that the ground is touched, i.e. the altitude must have dropped to a minimum value, and then the aircraft has reached a certain predetermined height. The number of such landing attempts is automatically counted using the method proposed here.

A device according to claim 10 is used to carry out the method according to the invention.

In addition to a real-time clock, the device includes a pressure sensor that measures the air pressure in the environment, a data memory to record the measured values of the air pressure and the time profile for at least a limited time, and a second memory that specifies the criteria specific to the aircraft to detect a takeoff or landing.

Another essential component of the device is a microprocessor, which processes the measured values of the air pressure and compares these and the stored values of the course of the air pressure with the criteria stored in the memory. If the comparison with the stored criteria reveals that a takeoff or a landing has taken place, the takeoff or landing time is determined by the microprocessor from the time profile of the air pressure and stored.

The use of a microprocessor and electronic storage media allows the device to be compact. It is therefore also characterized by its low weight and small construction. The device is thus portable and can be carried comfortably by the pilot during the flight.

The device preferably has a differentiator which determines the changes in air pressure from the measured values of the air pressure. In addition to the pure measured values of the air pressure, the changes in the air pressure are also available quickly and reliably and can be processed immediately by the other components of the device. This quasi real time determination of the Events enables particularly precise determination of takeoff and landing times.

In a preferred embodiment, the device has a display unit. The takeoff and / or landing time and other data relating to the aircraft are made visible in this display unit. The display unit can be designed as an LCD display. Multi-cell alphanumeric displays can preferably be implemented, so that multiple data and information can be made visible to the user at the same time.

In an advantageous embodiment, the device includes an interface for data transmission. On the one hand, this allows the data and information stored in the device to be transmitted to an external unit, for example a PC; the data can then be further processed in the external unit or archived for long-term storage. On the other hand, the interface enables the device itself to be supplied with data and information. For example, a number of aircraft-specific data can be stored, in particular identifiers and abbreviations for aircraft types or geographical locations.

It is advantageous if the device is powered by batteries. This ensures a power supply that is independent of the network, making the device self-sufficient and portable. The device can then be used in different locations and easily carried in your pocket.

The invention is explained below with reference to the accompanying drawings. Show it:

Fig. La the course of the air pressure during a start and

Fig. Lb the associated change in air pressure during takeoff;

2a shows the course of the air pressure during a landing;

2b shows the time course of the change in air pressure during a landing; - -

Fig. 3 is a schematic diagram of a device for determining the takeoff and / or landing times.

The negative pressure is plotted over time in FIGS. 1a and 2a. This representation was chosen because the negative pressure (-p) is proportional to the height (h) above the ground. This course thus reflects the course of the flight altitude of an aircraft. Figures lb and 2b show the changes in negative pressure, that is, the first derivative after time.

The drop in air pressure during a start is shown in FIG. In a first phase, which corresponds to rolling on the runway, the air pressure remains constant. Then the air pressure slowly drops first; later the pressure drop follows a straight line. The aircraft leaves the ground and gains altitude. Within this climb phase is also the start to be recognized, at which the aircraft has completely left the ground.

Figure lb shows the change in pressure over time. As long as the aircraft is taxiing on the runway, the pressure remains essentially constant; the change in air pressure is approximately zero. With the start of lifting from the ground, the change in pressure increases and finally reaches a constant value at a point in time from which the aircraft increases in height evenly. In the course of starting, the pressure change exceeds a predetermined threshold value S. If the pressure change remains above the threshold value S for at least a certain time Δt _s , the time at which the pressure change exceeds the threshold value S for the first time is defined as the start time (t _St ).

Figure 2a shows the time course of the air pressure during a landing. The diagram again shows the negative air pressure (- p), which is proportional to the flight altitude.

The aircraft swings into a descent from a constant flight phase with constant air pressure, which then goes into an interception phase. The pressure difference Δp is overcome during the descent phase. The duration of the interception phase Δt _ab must not exceed a predetermined period. The interception phase, during which the air pressure rises relatively slowly, is followed by touchdown on the runway (the actual landing) and the Phase of rolling out. Here the pressure p _{0 is} reached and remains essentially constant. The Ausrollphase must at least last for a time .DELTA.t _from. The landing to be recognized must be between the interception phase and the roll-out on the runway.

According to FIG. 2b, the landing time t _L can now be determined from the time course of the pressure change. The change in pressure is essentially zero as long as the pressure is approximately constant. The initiation of the descent is indicated by a decrease in the pressure change. The descent itself is characterized in that the pressure change falls below a predetermined limit value G. At the beginning of the interception phase, the change in pressure decreases and approaches the zero line again. No change in pressure can be registered during the roll-out, ie this is essentially zero. The landing time (t _L ) is now the time at which the pressure change has exceeded the limit value G again.

FIG. 2b shows that the roll-out phase of the aircraft on the ground differs from a flight phase at a constant height, in which the change in air pressure is equal to zero, only in that in the roll-out phase the course of the curve is significantly quieter and the individual values spread less. To distinguish these two phases, the measured values are compared with the averaged measured values. The averaging is based on at least 3, preferably on 10 values. The deviation of the individual measured values from the mean value is a simple criterion that can be checked quickly and without additional information.

Figure 3 shows the schematic structure of a device which works according to the methods described above.

The heart of the device is a microprocessor 1. This includes a program memory in which the specific criteria and a sequence program are stored, an intermediate memory for temporarily storing the measured values, the temporal course of the measured values and the changes in the values, and a non-volatile data memory which functions as an EEPROM is trained. The take-off and landing time, license plates and abbreviations for aircraft types and aircraft-specific data are stored in the data memory of the microprocessor 1. The results of previous flights can also be saved in a digital logbook. The amount of data that can be stored depends on the size of the available memory.

A pressure sensor 2, which is designed as an analog absolute pressure probe, continuously measures the air pressure. The measured values are firstly sent to a differentiator 3 and then to an A / D converter (analog-digital converter) 4 and, secondly, directly to the A / D converter 4. The differentiator 3 derives the pressure changes from the measured values of the air pressure. The A / D converter 4 digitizes the analog values and makes them available to the microprocessor 1 for further processing. The use of the differentiator 3 enables the changes in the air pressure to be determined very quickly and reliably. The microprocessor 1 thus immediately has the measured values required for the recognition of a takeoff and a landing in digital form and without a time delay.

The microprocessor 1 is also connected to a real-time clock 5. In addition to the measured values of the pressure, the times at which the measured values are recorded are also recorded. The time course can thus be determined. From the temporal course of the air pressure and from the values of the pressure change, the microprocessor 1 can record the fulfillment of the specified criteria and determine the takeoff or landing time from the temporal course of the measured values.

The determined takeoff and / or landing times are made visible in a display unit 6 connected to the microprocessor 1. The display unit 6 is designed as a multi-cell alphanumeric display. In addition to the takeoff or landing time, other information can also be output, such as aircraft type, identifiers or abbreviations for geographic locations.

An interface 7 is electrically connected to the microprocessor 1. This interface 7 is designed as a serial interface, in particular as an RS232 interface. However, other interfaces such as infrared, USB or Bluetooth interfaces can also be used. Via the interface 7 can _

the device can be connected to an external computer so that the stored data can then be further processed, saved or archived on the PC. With a connected PC, data and information can also be transferred to the device and data deleted.

Three manually operated buttons 8 are available to operate the device. With their help, the device can be initialized and individual modes can be selected. Furthermore, the buttons 8 are used to select the aircraft registration numbers stored in the internal memory. This includes the query of takeoff and / or landing times, the selection of different license plates for aircraft types, country or location codes and other logbook data.

The voltage supply is realized by two batteries 9. The voltage emitted by the batteries 9 is adapted by a DC-DC converter 10 to the voltage required by the microprocessor 1. The device works independently of external voltage sources and is therefore suitable for mobile use.

The device can be switched on and off via a switch 11 which is arranged between the batteries 9 and the DC-DC converter 10. In the switched-off state, only the data stored in the non-volatile memory of the microprocessor 1 are retained. The power consumption in the switched-off state is thus minimized and at the same time the useful life of the batteries 9 is extended.

Compilation of the reference symbols

microprocessor

pressure sensor

differentiator

A-D converter

Real Time Clock

display unit

interface

button

batteries

DC-DC converter

switch

Claims

claims

1. Method for determining the take-off and / or landing times of an aircraft, characterized by the following steps:

- Continuous measurement of the air pressure on the aircraft before, during and after take-off or landing;

- recording the time course of the air pressure;

- Detection of a takeoff or a landing based on predetermined criteria specific to the aircraft;

Define the take-off or landing time from the time course of the air pressure.

2. The method according to claim 1, characterized in that a start is detected when the speed at which the air pressure changes exceeds a predetermined threshold value for a certain period of time.

3. The method according to claim 2, characterized in that the time is set as the start time at which the speed of the change in air pressure exceeds the threshold value for the first time.

4. The method according to claim 1, characterized in that a landing is detected if the following criteria are met in succession: the speed at which the air pressure changes exceeds a predetermined limit value, the difference in air pressure exceeding a certain value;

- The speed of the change in air pressure does not fall below the limit value longer than a predetermined period of time; the air pressure remains essentially constant for at least a certain period of time.

5. The method according to claim 4, characterized in that the time is determined as the landing time at which the speed of the change in air pressure falls below the limit value for the first time.

6. The method according to any one of claims 1 to 5, characterized in that the take-off time or landing time is stored.

7. The method according to any one of claims 1 to 6, characterized in that the takeoff time or landing time is displayed in a display unit provided for this purpose.

8. The method according to any one of claims 1 to 7, characterized in that the takeoff time, the landing time and / or data relating to the aircraft are output via an interface.

9. The method according to any one of claims 1 to 8, characterized in that after at least one start, a landing attempt with subsequent take-off is recognized if the air pressure exceeds a predetermined first value and then falls below a predetermined second value, the first value being greater than the second value.

10. Device for determining the take-off and / or landing times of an aircraft by means of the method according to claim 1, with a real-time clock, characterized by a pressure sensor (2) for measuring the air pressure; a first memory to record the time course of the measured air pressure for at least a certain period of time; a second memory which contains predefined criteria specific to the aircraft for detecting a take-off or a landing; a microprocessor (1) in which the stored values of the air pressure are processed and compared with the stored criteria.

11. Apparatus according to claim 10, characterized by a differentiator (3) which determines the changes in air pressure from the measured values of the air pressure.

12. Device according to claim 10 or 11, characterized in that a display unit (6) for displaying the take-off and / or landing time and data relating to the aircraft is provided.

13. Device according to one of claims 10 to 12, characterized in that an interface (7) is provided for the transmission of data with an external unit.

14. Device according to one of claims 10 to 13, characterized in that the power supply by means of batteries (9).