NZ204535A - Direct display of data from a flight data recorder - Google Patents

Description

' •• ••'-- •-r- v rC;.-. ] 204535 Priority Date(s): 2$ ~?- ?Z Complete Specification Filed: Class: . .^(.^7.9...

Publication Date: P.O. Journal, No: ;23 JAN \987 /'if/.

WtNT ' ,5 * NEW ZEALAND No.: Date: PATENTS ACT, J 953 COMPLETE SPECIFICATION "AIRCRAFT FLIGHT DATA DISPLAY SYSTEM" 54 / We, SUNDSTRAND DATA CONTROL, INC., a corporation of the o State of Delaware, of Industrial Park, Redmond, Washington, 98052, United States of America '"A hereby declare the invention for which 3flx/ we pray that a patent may be granted to 83&c/us, and the method by which it is to be performed, to be particularly described in and by the following statement:- (followed by page -la-) 204535 — |ov- AIRCRAFT FLIGHT DATA DISPLAY SYSTEM BACKGROUND OF THE INVENTION The invention relates to the field of aircraft flight data display systems and in particular to flight data display systems that can visually display flight data directly from an aircraft flight data recorder.

Most of the commercial aircraft flying today are equipped with flight data recorders for recording various aircraft flight parameters such as altitude, airspeed, heading and engine data. The primary purpose for recording aircraft flight data is to provide flight data for accident analysis but the flight data recorded on the aircraft has also proven useful to airline management for other purposes including aircraft maintenance and incident analysis such as a landing approach resulting in a hard landing or a go-around. With the advent of modern digital flight data recorders that are capable of "storing over a hundred different flight parameters, the usefulness of the data to the airline operating and maintenance personnel has expanded dramatically. The availability of a large number of flight parameters has made possible significant improvements in the safety as well as economics of flight operations by permitting management to analyze actual flight data. However, in order to be useful, this data must be made available to management in a timely manner and in useful formats. 204535 A review of the prior art methods for producing aircraft flight data from a flight data recorder for analysis by airline personnel has revealed a number of significant disadvantages in these methods. Typically 5 the data from the digital flight data recorder, which is stored in bit serial form, has to be converted into a format that can be used as input to a large mainframe computer system. After the data from the digital flight data recorder is reformatted, the mainframe 10 computer system converts the data into the appropriate engineering units and this data is then printed out in tabular form or plotted for analysis. This process O has several disadvantages one of which is a substantial delay in making the data available. For example refor-15 matting or transcribing the data typically takes several hours and further delays often occur because the transcription equipment is remote from the location of the large mainframe computer. Also it has been found that the use of the company base computer can lead to 20 priority problems where the data conversion and tabulation processes quite often have to compete with other business functions of the machine resulting in further delays.

Along with the delays in making the data avail-25 able, a further disadvantage of the current procedure results from the fact that large quantities of computer w' printout are produced requiring extensive engineering time to examine and analyze. Thus the processes historically used by airline management to obtain 3 0 flight data lacks the flexibility to present timely data in a form that would be most useful to operating ^ and engineering personnel. 204535 ,-a SUMMARY OF THE INVENTION It is an object of the invention to provide a system for the direct display of selected flight data from an aircraft digital flight data recorder which overcomes at least some of the above mentioned disadvantages or provides the public with a useful choice.

Accordingly the invention may be said to consist in a system for the direct display of selected aircraft flight data from an aircraft flight data recorder, comprising: interface means operatively connected to a flight data recorder, for converting serial flight data from the flight data recorder into into flight data words; data storage means for temporarily storing said data words;' processor means, operatively connected to said interface means and said data storage means, for causing said interface means to receive said, serial flight data from the flight data recorder and to ..convert said serial flight data to said flight data words, for storing said flight data.words in a first predetermined location in said data storage means,- for converting selected flight data from said flight words into scaled flight data, and for storing said scaled flight data in a second predetermined location in said data storage .means; and display means operatively connected to said processor means for visually displaying'said scaled flight data stored in said second predetermined location. 204535 BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a functional block diagram of an aircraft flight data display system; Fig. 2 is a functional block diagram of an interface circuit for use with the aircraft flight data display system of Fig. 1; and Fig. 3 is an illustration of a visual display unit with an example of graphical display of flight data.

DETAILED DESCRIPTION OF THE INVENTION Fig. 1 provides an overall functional block diagram of the preferred embodiment of a system for directly displaying selected aircraft performance data from a digital flight data recorder. Aircraft performance data relating to such factors as aircraft speed, altitude, vertical acceleration, engine pressure ratios and pitch and roll attitudes is accumulated and stored during flight in an aircraft flight~data recorder indicated at 10. Some of the more recent flight data recorders such as the Sundstrand Data Control universal flight data recorder part no. 980-4100 are capable of storing twenty-five flight hours of over one hundred different flight parameters. In a digital flight data recorder such as the one indicated at 10, the data is typically stored in a bit serial format consisting of frames that in turn are divided into four subframes each one of which consists of sixty-four twelve bit words. Formats of the data stored in commercial flight data recorders are described in the ARINC specifications 573 and 717 published by Aeronautical Radio, Inc., Annapolis, Maryland. Each subframe represents one second's worth of aircraft performance data. In most cases each 204535 -5-- C o the twelve bit words represents an aircraft flight parameter such as altitude or airspeed with some parameters such as vertical acceleration being recorded several times during the one second intervals and therefore appearing in more than one word in a subframe. Similarly some types of data such as engine speeds are recorded only once in every frame or once every four seconds. The first word in each subframe consists of a sync word which both serves to mark the beginning of a subframe and to identify the subframe. Currently there are two different subframe formats, depending upon the manufacture of the data accumulation equipment installed in the aircraft. The binary values of the ARINC 573 sync words are provided below: SUBFRAME 1 2 3 4 FORMAT 1 Binary Value 111 000 100 100 000 111 011 010 111 000 100 101 000 111 011 011 FORMAT 2 Binary Value 001 001 000 111 010 110 111 000 101 0"01 000 111 110 110 111 000 iftL When it is desired to obtain and analyze the flight data contained in a flight data recorder 10, the flight data recorder 10 itself can be connected directly to a playback unit 11 that is associated with aircraft flight data display system shown in Fig. 1. However, since it is often impractical to remove the flight data recorder 10 from the aircraft, it may be more convenient to use a copy recorder as indicated by the dash line 14 to record the data from the flight data recorder 10 on the aircraft and then connect the copy recorder 14 as indicated by line 16 to the playback unit 11. Commercially available copy recorders such as the Sundstrand Data Control copy recorder part no. 981-6024-001 are capable of recording over twenty-five hours of flight data in approximately thirty minutes , R 204535 C o o o thereby eliminating the necessity for physically removing the flight data recorder 10 from the* aircraft.

One function of the playback unit 11 is to control the flight data recorder 14. For example in a digital flight data recorder the playback unit 11 can write a marker on the tape, command the tape to run in a forward or reverse direction and sequence through the tape tracks. The playback unit 11 also serves as a preprocessor of the data on the flight data recorder 10 or copy recorder 14 by squaring and decoding biphase signals into non-return to zero signals. Playback units are commercially available such as the Sundstrand Data Control playback unit part no. 981-1218.

Connected to the playback,unit 11 by means of a data line 18 is an interface board 12 connected to the central processing unit 20 of a mini-computer system such as the Data General Nova Model 4S which is a sixteen bit mini-computer and includes an input-output board 21. The central processing unit 20 is also connected through the I/O board 21 to a visual display unit 22 as indicated by line 24 which preferably includes a color graphics terminal having a color display cathode ray tube 26 and a keyboard 28. In the preferred embodiment of the invention the color graphics visual display unit 22 is the Advanced Electronic Design, Inc. AED5 12 color graphics imaging terminal that is described in detail in the AED5 12 Users' Manual available from Advanced Electronics Design, Inc. of Sunnyvale, California which is incorporated herein by reference. For some applications it may be desirable to connect a printer/plotter 30 as indicated by line 32 to the central processing unit 20 in order to produce tabular data in printed or plotted black and white form.

Another integral portion of the aircraft flight data display system as shown in Fig. 1 is the memory 204535 arrangement which in the preferred embodiment includes a high speed random access memory 34 along wi.th a lower speed bulk memory 3 6 which is preferably a disc memory: either floppy or fixed disc. As indicated 5 in Fig. 1, the memory is connected, as represented by a data line 38, to the central processing unit 20 as is the bulk memory 36 indicated by the line 40. In the embodiment of the invention shown in Fig. 1 the random access memory 34 is a part of the random access 10 memory normally supplied with the Nova 4S computer.

The organization of the high speed random access memory in the aircraft flight data display system includes a buffer portion 42 in a predetermined location in the random access memory 34 that is organized into a first 15 buffer 44 and a second buffer 46. Each of the buffers 44 and 4 6 are organized into sixteen subframes each of which in turn are broken down into sixty-four sixteen bit words. In addition to the buffer memory the high speed random access memory 34 includes a set of con-20 version tables to aid in converting the raw aircraft performance data from the flight data recorder 10 into data in engineering units 48, an extracted data buffer 50 for temporarily storing selected portions of the raw aircraft performance data extracted from the 25 buffer 4 2 and a converted data buffer 52 for temporarily storing aircraft performance data that has been con-CD verted and scaled into engineering units. As is conventional, the random access memory 34 also includes a predetermined location 54 for storing at least a 30 portion of the computer program driving the central processor 20 and a location 56 for storing the computer Q operating system. The bulk or disc memory 36 includes a portion 58 for storing a parameter data base, a portion 6 0 for storing a plot data base as well as 35 portions 62 and 64 for storing the computer program and the computer operating system. £#0^ f ** -10CT1986 S) . -- ■: '^,7 J V- - -■»- - - 20453S -8- • In Fig- 2 is provided a detailed functional block diagram of the interface board 12 which- in the preferred embodiment is implemented on a circuit board within the computer. Bit serial flight data from the flight data recorder or the copy recorder 14 is transmitted over the data line 18 through the playback unit 11 and on data line 18 to a serial to parallel converter 66. The serial to parallel converter 66 includes two 8 bit shift registers for converting the serial data received on line 18 to twelve bit parallel words which then are transmitted by means of a data bus 68 to an I/O data bus transceiver 70. The serial to parallel converter also includes a data register for temporarily storing the twelve bit data word long enough so that it can be transmitted via the data bus 68 to the random access memory 34. A new twelve bit data word is latched into the data register every twelve strobe cycles which are transmitted from the playback unit 12 over a line 69. The data bus 68 is a sixteen bit parallel data bus in order to conform with the sixteen bit data system of the central processor unit 2 0 and as a result the four most significant bits of each data word applied to the bus 68 are zeroed out. As shown in Fig. 2 the I/O data bus transceiver 70 is connected to a data bus 71 for transmitting data to the central processing unit 20 or the high speed random access memory 34 shown in Fig. 1 via the I/O board 21. Also connected to the serial to parallel converter 66 by means of a twelve bit data bus 72 is a sync word detector 74. The sync word detector 74 includes four twelve bit data registers for holding the four sync words which are being sought as well as four comparator circuits which are effective to generate signals on a pair of lines 76 and 73 to indicate which of the four sync words have been detected. Connected to the lines 76 and 78 is a status word register 80. The status word 204535 o register 8 0 is connected by means of a pair of control lines 82 and 84 to an interrupt control circuit 86.

Along with the status word register 80, a word/ bit counter circuit 88 is connected to the interrupt .5 controller 86 by means of a pair of control lines 9 0 and 92 and a clock signal line 94. The word/bit counter 88 receives the strobe signal over line 96 which represents each bit received by the serial to parallel converter 66 over the line 18 from the flight 10 data recorder 10 or the copy recorder 14. Thus the word/bit counter 88 is effective to count the number of data bits being received by the interface board of Fig. 2 and to generate the appropriate control signals to the interrupt controller 86 along with the clock 15 signal that increments a word counter in the word/bit counter 88. In addition the word/bit counter 88 contains a status- register containing accumulated word/bit counts per subframe.

The interface board of Fig. 2 also includes a 20 data channel controller 9 8 operatively connected to the serial to parallel converter 66 by means of a control line 100 and to the central processing unit 20 by means of control lines 102 and 103.

Also included in the interface circuit of Fig. 25 2 is a command word register 104 that is connected either to the copy recorder 14 or the flight data / ' // v recorder 10 by means of control lines 106. The I'i vigor^ | - tOCTlVoOr, command word register 104 provides a means for v. / controlling the playback unit 11. Information is '• A • 30 transmitted from the central processing unit 20 over the data bus 71 through the I/O data bus transceiver to the data channel controller 98 the sync word detector 74 and the command word register 104 by means of a data bus 108. It should also be pointed 35 out that the interrupt controller 86, the status word register 80 and the data channel controller 98 are connected to the input data bus 68 along with the 204&3S Q 20 25 O o serial to parallel converter circuit 66. The serial to parallel converter 66 and the status word register 80 are also connected by means of control lines to the command word register 104 by control lines 110 and 112 respectively. Similarly the word/bit counter 88 is connected to the data channel controller 98 by means of a clock signal line 114 and the sync word detector 74 is connected to the interrupt controller 8 6 by means of a control line 119. Interrupt signals are generated by the interrupt controller 86 and transmitted directly to the central processing unit 20 over the control line 116. Detailed design criteria with respect to communication of the interface board 12 with the preferred central processing unit is provided in the "Users' Manual - Interface Designer's Reference, Nova and Eclipse Line Computers" publication no. 014-000629-00 of the Data General Corporation incorporated by reference herein.

The process of providing a visual display of aircraft flight data from the flight data recorder 10 on the visual display unit 22 begins with tKe initialization of the interface circuit 12 by the central processing unit 20 of Fig. 1. Under control of the central processing unit 20 resulting from the logic program stored in the program memory 54 the appropriate sync words are transmitted over the data bus 71 to the interface board of Fig. 2 and by means of the output data bus 108 to the registers in the sync word detector 74. A hardware word address indicated the location of the first word in the first buffer 42 in the high speed random access memory 34, where the aircraft flight data that has been converted to twelve bit words by the serial to parallel converter 66 is to be stored, is similarly transmitted over the input data bus 71. This address is stored in a register in the data channel controller 98. In order to prov r-10CT?9S5": 204535 -n- a data path to the central processing unit 20 and memory 34, a data channel request signal is transmitted from the data channel controller 98 on line 102 to the central processing unit 20 and acknowledged by a signal on line 103. After the sync word detector 74 has been initialized with the appropriate sync words, a start signal is transmitted from the command word register 104 over the lines 106 to the playback unit 11 and then by means of a control line 117 to either the copy recorder 14 or the data recorder 10 depending on which one is connected to the playback unit 11.

When the start signal has been received the flight data recorder 10 or the copy recorder 14 will start transmitting the flight parameter data via the playback unit 11 to the serial to parallel converter 66. At the same time, when each twelve bit parallel word is generated in 66, line 114 is strobed to indicate a word has been formed. Line 102 is strobed to request access to the data channel. After data channel acknowledge signal 103 is returned from the CPU 20 the parallel word is transferred on line 68 through 70 to buffer 42. This flight parameter data which has been converted to the twelve bit word format is transmitted by means of line 72 to the sync word detector 74 and when any one of the four sync words has been detected by the sync word detector 74 a sync interrupt signal is generated and transmitted by means of line 119 to the interrupt controller 86. At the same time the particular sync word is identified by the status word register 80 from the signals on lines 76 and 78 which serve to identify the particular sync word found by the sync word detector. From the information contained in the status word register 80 the central processing unit 20 calculates the memory address where the particular subframe of data as identified by the sync word should be stored in the buffers 44 or 46 of the high speed random access I ■12- 204535 O memory 34 and that address is transmitted to the address register in the data channel controller 98. For example if the first sync word detected represented the third subframe the hardware memory address calcu-• 5 lated by the central processing unit 20 would be the start of the subframe "2" as shown in buffer 44.

Once a sync word has been identified by the sync (/T*) word detector 74 the interface board Fig. 2 then begins to directly transfer the synchronous raw flight param-10 eter data by means of the I/O data bus transceiver 7 0 over the data bus 71 through a dedicated data channel directly to the locations in the buffer memory 4 2 as indicated by the address contained in the address register in the data channel controller 98. Each time 15 the word/bit counter 88 detects twelve bits, the clock signal is transmitted on line 114 which increments the word address in the word register of the data channel controller 98 thereby resulting in the next data word being placed in the next word of the buffer memories 42. 20 As each subframe in the buffer memory 42 is.filled, a count of the subframes is kept by the central processing unit 20 in a counter 120 in the random access memory 34. When the last subframe "15" in the second buffer 46 has been filled, the central processing 25 unit 20 will cause the system to start writing the data in the first buffer 4 4 by supplying the address ^ of the first word in that buffer to the data channel controller. In this manner only a limited amount of random access memory is required for processing the 30 flight data. Since the flight parameter data is being automatically transmitted directly to the buffer memory 42 the central processing unit 20 is free to begin to convert the raw flight parameter data contained in the buffer units into engineering units such as feet, 35 knots or degrees for display by the visual display unit 22. -10CT 1986' One of the primary functions of the word counter in the word/bit counter 88 is to count the niimber of data words received since the last sync word was detected by the sync word detector 74. When the count reaches 63, a clock signal generated on line 94 signifies that the last data word of a subframe is about to be received. This has the effect of putting the interface board onto a sync search mode. When the next sync word is detected by the sync word detector 74 both of the bit and word counters in the word/bit counter 88 are reset to zero.

One of the functions of the word/bit counter 88 is to count the number of data bits received by the serial to parallel converter 66. In the event that 65 words have been received by the serial to parallel converter 66 and a sync word has not been detected by the sync word de-tector 74 an overflow signal is generated in the interrupt controller 8 6 over line 92 causing the central processing unit 20 to.interrupt the conversion process and to calculate a memory address for the buffer memory based on an assumption of the nature of the flight data received and where it should be stored in the buffer memory 42. This memory address is then transmitted to the address register in the data channel controller 98. In addition the CPU 20 will cause error flags to be set in E the buffer memory indicating that this particular ^ flight data being loaded in the buffer memory is questionable or may be in error. In addition the central processing unit 20 creates the appropriate reformatted sync words to be stored in the buffer memory 42 for the data that has been received without the sync word being detected by the sync word detector 74. In this manner it is possible to continue to load flight performance data in the buffer memory 4 2 and make it available to the display unit 22 even when a sync word has not been detected so that r-10CTl986 204535 % *• & i i I | 1 *" J ' o o O valuable flight performance data is not lost just because there may be an error in the sync word contained in the data.

Before the data conversion process can take place, usually during initialization of the system, the appropriate parameters and flight data units must be selected. This is usually done by an operator utilizing the keyboard 28 of the visual display unit. When the appropriate flight data parameters and units have been selected, this information is transmitted by the visual display unit 22 to the central processing unit 20 which then causes the appropriate parameters from the parameter data base 58 to be transmitted from the bulk memory 36 to the conversion tables 48 in the high speed random access memory 34. After the initialization has been completed, selected flight parameters, for example airspeed or altitude, are removed from the raw flight performance data contained in the buffer 42 and placed in the extracted data buffer 50. This process is only started after an interrupt has been generated on line 116 by interrupt controller 8 6 so that a full subframe is identified and stored in the first appropriate location in the first buffer 44 and it is possible to ensure that the appropriate data words from this first subframe loaded in the buffer memory 4 4 are available for loading into the extracted data buffer 50. In particular after a full subframe of data has been loaded in the first buffer memory 44, the information contained in the conversion tables 4 3 is used to determine word location within the subframe and the data bits within the word to be accessed in order to extract the portions of the raw data which represent the selected flight parameter value. This extracted raw data is then placed in the extracted data buffer 50. The conversion of raw data to data that is scaled in the appropriate engineering uni' 30463S- L-> O occurs after all of the selected parameters have been transferred from the subframe in the buffer memory 44. Associated with each flight parameter is a parameter code contained within the conversion tables 48 that determines the specific process for converting the raw flight data into the appropriate scaled engineering units for display on the visual display unit.

The processor 20 converts the flight parameters of interest from raw data values to engineering units by use of conversion processes keyed to the parameter type code. The conversion process proceeds with the system sequentially comparing the table of requested parameter types with its own table of possible parameter types. When a match between tables is found, the system branches to apply t'he unique conversion process for the respective parameter type. Once the raw data is converted to the final engineering units value, it is stored in the converted data buffer 52 and a process for maximum/minimum limits exceedance checking, if requested during initialization, is performed. This procedure assigns maximum or minimum values to predefined flight parameters such as altitude or airspeed so that if these values are exceeded by the actual flight data an indication can be flashed on the CRT 26 of the visual display unit 22.

All parameters (excluding BCD and discrete parameters) defined in the parameter data base 58 can have, along with their unique scale factor and offset, a look-up table consisting of from 2 to 4 0 pairs of data values and corresponding engineering units. In general, after the offset and scale factor have been applied to the raw data value giving an intermediate engineering units result, linear interpolation into the look-up table is accomplished if the table exists. The general flow of the conversion process is as follows: 204535* raw data: offset and scale factor intermediate result: look-up table final engineering units In the detailed explanation of the conversion process the following abbreviations are used: EU - final calculated Engineering Units IR - intermediate result after one or more calculation steps Rl - raw data least significant word R2 - raw data most significant word R3 - raw data third word (pneumatic altitude conversion algorithm index) SD - synchro angle in degrees FD - fine synchro angle in degrees CD - coarse synchro angle in degrees Parameter type: Al (analog parameter from single data word) IR = (Rl - offset) * scale factor EU = IR : table look-up Parameter type: A2 (analog parameter from two data words) IR = (R2 * 4096) + Rl IR = (IR - offset) * scale factor EU = IR : table look-up Parameter type: D1 (digital (.signed) parameter from single data word) (sign may be from a second data word) IR = (.+/") Rl IR = (IR - offset) * scale factor EU = IR : table look-up Parameter type: D2 (digital (signed) parameter from two data words) (sign must be from second data word) IR = (R2 * 4 096) + Rl IR = (+/-) IR EU = IR : table look-up 204535 Parameter type: XI (discrete parameter from single data word) EU = Rl Parameter type: X2 5 (discrete parameter from two data words) EU = (R2 * 2) + Rl Parameter type: G2 (GMT coded as a BCD value in two data words) EU = HH:MM (hours and minutes converted 10 from BCD to ASCII characters) Parameter type: HI (linear (Hamilton Standard) synchro from single data word) sd = Rl : linear synchro conversion 15 IR = (sd - offset) * scale factor EU = IR : table look-up Parameter type: H2 (linear (Hamilton Standard) synchro from two data words (altitude)) 20 CD = R2 : linear synchro conversion FD = Rl : linear synchro conversion if CD is greater than or equal to 350 degrees, then CD = CD - 360 IR = ((.CD * 375) - (FD * 13.839) )/5000 25 IR = IR : rounded to nearest integer value IR = (FD * 13.889) + (IR * 5000) \ IR = (IR - offset) * scale factor EU = IR : table look-up Parameter type: T1 30 (.non-linear (Teledyne) synchro from single data word) SD = Rl : non-linear synchro conversion IR = (SD - offset) * scale factor EU = IR : table look-up > o ojj tr:?' -10CT1986 \a ^ / 204535 Parameter type: T2 (non-linear (Teledyne) synchro from two., data words (altitude)) CD = R2 : non-linear synchro conversion FD = Rl : non-linear synchro conversion if CD is greater than or equal to 350 degrees, then CD = CD - 360 IR = ((CD * 375) - (FD * 13.889)/5000 IR = IR : rounded to nearest integer value IR = (FD * 13.889) + (IR * 5000) IR = (IR - offset) * scale factor EU = IR : table look-up Parameter type: PI (pneumatic parameter from single data word (UFDR pneumatic airspeed)) IR = Rl * 0.0025 voltage IR = (IR * scale factor) - offset : PSID IR = IR * 144000 : PSFD * 1000 IR = IR : interpolated from pressure vs.

EU = IR : table look-up Parameter type: P3 (pneumatic parameter from three data words (UFDR pneumatic altitude)) choose conversion algorithm based upon the value of R3 (conversion algorithm index) airspeed table index 0 determine transducer calibration factors from table 0 index 1 determine transducer calibration factors from table 1 index 2 to 7 - determine transducer calibration factors from table 0 conversion algorithm for index 0 to 7: m 204535 r) /"*"■, 25 TT = R2/10.2 : transducer temperature OT = : calibration factor interpolated from indexed table by temperature TT KT = : calibration factor interpolated from indexed table by temperature TT IR = (4096 - Rl) * 0.0025 IR = (IR - OT)/(0.414 * KT) IR = (IR - offset : PSIA) IR = IR * 144000.0 : PSFA * 1000 IR = IR : interpolated from pressure vs. altitude table EU = IR : table look-up After the flight data parameters have been scaled into the appropriate engineering units they are stored in the converted data buffer 52. The information contained within the converted data buffer 52 is then translated by the central processing unit into a format that is compatible with the particular visual display unit 22 for direct display on the cathode ray tube 26. It should also be noted that this infomration may be transmitted directly over a line 32 to the printer/plotter 30 for tabular listing or plotting of the aircraft flight parameter data if so desired.

In Fig. 3 is provided an illustration of the graphical output of the flight data display system. A front view of the visual display unit 22 is shown with a representative example of a graphical display of flight data projected on the CRT 26. In this example four flight parameters: altitude, airspeed, heading and vertical acceleration are plotted against time in seconds on the lower vertical axis 122 for an aircraft during take-off. The dashed line 124 represents aircraft altitude; the double dot line 126 represents airspeed; the single dot line 128 represents ?? e'C5£^ 204535 -20- - O o magnetic heading and the solid line 13 0 represents vertical acceleration. Values for the flight." parameters are displayed on. a segmented grid represented by lines 132 and 134. Since the preferred visual display unit 22 is a color graphics terminal, the various portions of the display are produced in color wherein for instance the altitude line 124 is yellow, the airspeed line 126 is green, the heading line 128 is light blue and the vertical acceleration line 130 is red with the segmented grid lines 132 and 134 in dark blue. In this particular case the display on the CRT 26 is generated one segment or pixel at a time and scrolled to the left. The central processing unit 2 0 will provide one second worth of data from the converted data buffer 52 at a time so 'that the visual display unit 22 can generate the display pixel by pixel. Then an operator by using the keyboard 28 can scroll the display on the CRT 26 to the right or the left to view the desired data.

Since the visual display unit 22 serves to both initialize and control the system by means of the keyboard 28 resulting in signals transmitted to the central processing unit 20 on line 136, an operator can define the desired flight parameters and start the input of flight data from the flight data recorder 10 or copy recorder 14 into the system by using the keyboard 28. In the preferred embodiment, up to eight different flight parameters along with two discretes can be displayed at any one time. The operator additionally has the ability to control the operative copy recorder 14 through the keyboard 28 by commanding it to: start, stop, select a particular track, hold or continue by means of the control functions transmitted through the central processing unit 20 and the playback unit 11. Also, because the preferred visual display unit has a zoom capability, the operator is able to enlarge or focus in on any particular flight 204535 parameter that he is interested in by utilizing the controls on the keyboard 28. fO 0 O

Claims (1)

1. -22- 204535 What we claim is: 1. A system for the direct display of selected aircraft flight data from an aircraft flight data recorder, comprising: interface means, operatively connected to a flight data recorder, for converting serial flight data from the flight data recorder into flight data words; data storage means for temporarily storing said data words;' processor means, operatively connected to said interface means and said data storage means, for causing said interface means to receive said serial flight data from the flight data recorder and to convert said serial flight data to said flight data words, for storing said flight data words in a first predetermined location in said data storage means,- for converting selected flight data from said flight words into scaled flight data, and for storing said scaled flight data in a second predetermined location in said data storage.means; and display means operatively connected to said processor means for visually displaying said scaled flight data stored in said second predetermined location. processor means additionally includes means for converting said scaled flight data into a format acceptable to said display means and means for transmitting said converted flight data to said display means. data storage means includes a high speed random access memory and wherein said first and said second predeter- memory, 4. The system of claim 1, wherein said first predetermined location includes a first and second buffer area and wherein said processor means includes means for loading sequentially said first buffer area and then said second buffer area with said flight data words and means for sequentially loading said first buffer 2. The system .of claim 1, wherein said 3. The system of claim 1, wherein said mined locations are in said high speed random access pv a: | - 10CTI9&6 I ' -23- 204535 area with flight data words after said second buffer area has been filled with, said flight data words. 5. The system of claim 1, wherein said interface means includes detector means for detecting a sync word in said serial flight data and generating a sync signal identifying the sync word detected and wherein said processor means includes means for initating said conversion of flight data words into said scaled flight data in response to said sync signal. 6. The system of claim 5, wherein said interface means includes means responsive to said Sync signal for directly loading said flight data words into said first predetermined location. 7. The system of claim 6, wherein said processor means includes means responsive to said sync signal for generating an address in said first predetermined location for storing said flight data words in sequence and transmitting said address to said interface means. 8. The system of claim 7, wherein said interface means includes means for transmitting said flight data words to said first predetermined location prior to identifying a sync word. 9. The system of claim 1, wherein said interface means includes a counter means for counting said flight data words and generating an overflow signal indicating that a predetermined number of flight data words have been received and transmitted to said first predetermined location without a sync word being detected and wherein said processor means includes data overflow means responsive to said overflow signal for tentatively identifying said flight data. 10. The system of claim 9, wherein said data overflow means generates an address for storing said tentatively identified data in said predetermined^-^— location and generates a signal indicating that said^^^ E ^ ^3% 204535 tentatively identified data may be in error. 11. The system of claim 1, wherein said data storage means includes conversion factors stored in a third predetermined location. 12. The system of claim 11, wherein said processor means includes means for extracting predetermined elements of flight data from said first predetermined location and storing said flight data elements in a fourth predetermined location in said data storage means. 13. The system of claim 12, wherein said processor means includes means for calculating said scaled flight data from said flight data elements and said conversion factors and storing said scaled flight data in said second predetermined location. 14. The system of claim 1, wherein said processor means converts said selected flight data into engineering units, and wherein said display means includes a keyboard to select said selected flight data for conversion into engineering units. 15. The system of claim 14, wherein said display means includes means for controlling said source of flight data. 16. ' The system of claim 14, wherein said processor means performs said conversion of said selected portions of flight data into engineering units while said interface means is reformatting and storing the flight data and while said display means is displaying said converted flight data. 17. The system of claim 14, wherein said interface means includes a sync word detector circuit for detecting sync words in the flight data. 18. The system of claim 17, wherein said interface means includes a circuit for generating flight -25- 204535 19. The system of claim 18, wherein said data storage means includes a high speed random access memory and said addresses represent locations in said high speed random access memory. 20. . The system of ,claim 3, including a bulk /(<5iA>L^ fciiJ L/» memory; and^a central processing unit operatively connected to said interface unit and said high speed random access memory and said bulk memory. 21. A system for the direct display of selected aircraft flight data from an aircraft flight data recorder substantially ' as hereinbefore described with reference to the accompanying drawings. ' '*■ , ' . tf\: 'X & SVi-*. K 1 ' rs •*< f "