Note: Descriptions are shown in the official language in which they were submitted.
AIRCRAFT FLIGHT DATA DISPLAY SYSTEM
BACKGROUND OF THE INVE~TION
The invention relates to the field of aircraft
1ight da~a 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 var-
ious 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 man-
ag~ment for other purposes including aircraft mainte-
nance and incident analysis such as a landing approach
resulting in a hard landin~ or a go-around. With the
advent of modern digital flisht data recorders that are
capable of storing over a hundred different flight
par~neters, the usefulness of the data to the airline
operating and maintenance personnel has xpanded
dramatically. The availabili~y 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.
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A review of the prior art methods for producing
aircraft flight data from a flight data rec~rder for
analysis by airline personnel has revealed a number of
significant disadvantages in these methods. Typically
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
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
has several disadvantages one of which is a substantial
delay in making the data available. For example refor-
matting or transcribing the data typically takes sev-
eral 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
priority problems where the data conversion and tabu-
lation processes quite often have to compete with
other business functions of the machine resulting in
further delays.
Along with the delays in making ~he data avail-
able, a further disadvantage of the curren~ procedure
results from the fact that large quantities of computer
printout are produced requiring extensive engineering
time to examine and analyze. Thus the processes
historically used by airline management to obtaln
flight data lacks the flexibility to present timely
data in a form that would be most useful to operating
and engineering personnel.
7~
S~MMARY VF THE INVENTION
It is the object of the invention to provide
a system for displaying flight data from an aircraft
- digital flight data recorder which includes: a data
storage unit; an input unit for accepting flight data
from a data storage uni~; a processor for converting
selected portions of the reformatted flight data into
engineerins units and storing the converted flight
data in the storage unit; and a video display unit
including a keyboard effective to cause the processor
to select portions of the reformatted flight data for
conversion into flight data engineering units and to
display the converted fliyht dataO
It is an additional object of the invention to
provide for the direct display of selected digital
flight data from an aircraft flight data recorder with
a system that includes: a data storage unit; an input
unit; a processor for converting selected portions of
the flight data into engineering units in response to
a sync word in the data while flight data from the
source of flight data is being stored in the data
storage unit, and a display uni~ for displaying the
dat~ converted into engineering units.
It is a further object of the invention to
provide for the direct display of selected aircraft
flight parameters from an aircraft digital flight
data recorder with a display system that includes:
an interface circuit connected to the flight data
record~r for converting serial flight data into flight
data words; a data storage unit for temporarily
storing the data words; and a data processor for
causin~ the interface circuit to input serial flight
data from the flight data recorder and to convert the
serial data into a word format, storing the flight
data words in a first predetermined location in the
7~7~,
data storage unit, converting said flight data words
into scaled flight data, and s1oring the scaled
flight data in a second predetermined loca~ion in
the data storage unit; the system also includes a
S display unit responsive to the processor for visually
displaying the scaled flight data stored in the data
storage unit.
It is another object of the invention to provide
a system for the display of flight data derived from
an aircraft flight data recorder that includes: a
source of raw flight data; an interface unit effective
to reformat the raw flight data; a high speed random
access memory; a bulk memory; a central processing
unit effective to cause the interface unit to load
the reformatted raw flight data into a firs~ location
in the random access memory, to convert selected
portions of the raw flight data into engineering units
and to store the converted flight data ~n a second
locatlon in the random access memory; and a visual
display unit effective to display the converted flight
data stored in the second location in the random
access memory.
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BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a fllnc~ional block diagram of an
aircraft flight data display systemi
Fig. 2 is a functional block diagram of an
interface clrcuit for use with ~he aircraft flight
data display system of Fig. l; and
Fig. 3 is an illustration o-f a visual display
unit with an example of graphical display of flight
data.
DETAILED DESCRIPTION OF THE INVENTION
Fig. 1 provides an overall runctional b]ock
diagram of the preferred embodiment of a system for
directly displaying selected aircraft performance data
from a digital flight data recorder. Aircraft perfor-
mance data relating to such factors as aircraft speed,
altitude, vertical acceleration, ensine 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 indi-
cated at 10, the data is typically stored in a blt
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 o the data
stored in commercial flight data recorders are de-
scribed 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 of
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the twelve bi~ words represents an aircraft flight
parameter such as altitude or airspeed with ~ome
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
beainning of a subframe and to identlfy the subframe.
Currently there are two different subframe formats,
depending upon the manufacture of the data accumula-
tion equipment installed in the aircraft. The binary
values of the ARINC 573 sync words are provided below:
FORMAT 1 FOR~AT 2
SUBFRAME Binary Value Binary Value
111 000 100 100 001 001 000 111
2 000 111 011 010 010 110 111 000
3 111 000 100 101 101 001 000 111
4 000 111 011 011 110 110 111 000
When it is desired to obtain and analyze the
flight data cGntained 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 i5 often impractical to remove the flight
data recorder 10 from the aircraft, it ~ay 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 record~ng over twenty-five
hours of flight data in approximately thirty minutes
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1 thereby eliminating the necessity for physically remvving
the flight data recorder 10 from the aircraft.
One functi.on of the playback unit 11 is tc
control the flight data recorcler 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 tracksc The playback unit 11 also serves as
a preprocessor of the data on the flight data recorder
10 or copy recorder 14 by s~uarin~ and decoding biphase
signals into non-return to zero signals.. Playback units
are commercially available such as ~he Sundstrand Data
.Control playback unit part no. 981~1218.
Connected to the playback unit 11 by means of
a data l.ine 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 sixt~en bit mini-co~puter 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 prefer-
ably includesa color graphics terminal having a color
display cathode ray tube 26 and a keyboard 28. In
the preferred embodiment of the invention the cclor
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
Usersl Manual available from Advanced Electronics
Design, Inc~ of Sunnyvale, California. 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
! ~ .
r~P 77;~
arrangement which in the pxeferred embodiment includes
a high speed random access memory 34 along with a
lower spe~d bulk memory 36 which is preferably a disc
memory: either floppy or fixed disc. As indicated
in Fig. 1I the memory is connected, asrepresented 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 tne random access
memory normally supplied with the Nova 4s computer.
The organization of the high speed random access memory
ln 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
buffer 44 and a second buffer 46. Each of the buffers
44 and 46 are organized into sixteen subframes each of
which in turn are broken down into sixty-four sixteen
bit wordsO In addition to the buffer memory the high
speed random access memory 34 includes a set of con-
version tables to aid in converting the raw aircraftperformance data from the flight data recorder 10 into
data in engineering units 48, an extracted data buffer
50 for temporarlly storing selected portions of the
raw aircraft performance data extracted from the
buffer 42 and a converted da~a buffer 52 for temporarily
storing aircraft performance data that has been con-
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
3 a portion of the computer program driving the central
processor 20 and a location 56 for storing the computer
operating system. The bulk or disc memory 36 includes
a portion 58 for storing a parameter data base, a
portion 60 for storing a plot data base as well as
portions 62 and 64 for storing the computer program
and the computer operating system.
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g
In Fig. 2 is provided a detailed functional
block diagram of the interface board 12 whic~ in the
preferred embodiment is impl~nented on a circuit board
within the computer. Bit serial flight data from the
flight data recorder or the copy recorder 14 is trans-
mitted over the data line 18 through the playback
unit 11 and on data line 18 to a serial to parallel
convexter 66. The serial to parallel converter 66
includes two 8 bit shift registers for converting the
serial data received on line 18 ~o twelve bit paxallel
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 slxteen bit data system of the central
processor uni~ 20 and as a result the four most sig-
nificant 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 ~or
transmitting data to the central processing unit 2
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 78 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
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register 80 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
controller 86 by means of a pair of control lines 90
and 92 and a clock signal line 94. The word/bit
counter 88 receives the strobe signal over llne 96
which represents each bit received by the serial to
parallel converter 66 over the line 18 from the flight
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
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
data channel controller 9~ 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.
2 is a command word register 104 that is connected
either to the copy recorder 14 or the flight data
recorder 10 by means of control lines 106. The
command word register 104 provides a means for
controlling the playback unit 11. Information is
transmitted from the central processing unit 20 over
the data bus 71 through the I/O data bus transceiver
to the data channel controller 93 the sync word
detector 74 and the command word register 104 by
means of a data bus 108. It should also be pointed
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
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1 serial to parallel converter circuit 66. The serial
to paralle.l conv~rter 66 and the status word register
80 are also connected hy means of colitrol llnes 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 86 by
means of a control line 119. Interrupt signals are
generated by the interrupt controller 86 and transmitted
directly to t.he central processing unit 20 over the
control line 116c Detailed design criteria with
respeot to communication of the interface boaxd 12
wi.th the preferred central processing unit is provided
in the "Users' Manual - Interface Designer'~ Referencer
Nova and Eclipse Line Computers" publication no.
014-000629 00 of the Data General Corporation r
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 the initial-
ization o the interface circuit 12 by the central
processing unit 20 of Fig~ 1D 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 air-
craft 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 provide
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a data path to the central processing unit 20 and
memory 34, a data channel request signal is t-rans-
mitt~d from ~he data channel controller 98 on line
102 to the central processing unit 20 and acknowledged
- 5 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 pla~back
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 heen 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 gen-
erated 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 7~ 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 in~errupt
controller 86. At the same tLme the particular sync
word is identified by the status word register 80 from
the signals on llnes 76 and 78 which serve to identify
the particular sync word found by the sync word detector.
From the information con~ained 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
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memory 34 and tha~ address is ~transrnitted to the
address register in the data channel control~er 98.
For example if the first sync word detec~ed represented
the third subframe the hardware memory address calcu-
lated by the central processing unit 20 would be thestart of the subframe "2" as shown in buffer 44.
Once a sync word has been identified by the sync
word detector 74 the interface board Fig. 2 then begins
to directly transfer the synchronous raw flight param-
eter data by means of the I/O data bus transceiver 70over the data bus 71 through a dedlcated data channel
directly to the locations in the buffer memory 42
as indicated by the address contained in the address
register in the data channel controller 98. Each time
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.
As each subframe in the buffer memory 42 is filled, a
count of the subframes is kept by the central process-
ing unit 20 in a counter 120 in the random access
memory 34. When the last subframe "lS" in the second
buffer 46 has been filled, the central processing
unit 20 will cause the system to start writing the
data in the first buffer 44 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
flight data. Since the flight parameter data is being
automatically transmit ed directly to the buffer memory
42 ~he central processing unit 20 is free to begin to
convert the raw flight parameter data containe~ in the
buffer units into engineering units such as feet,
kno~s or degrees for display by the visual display
unit 22.
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One of the primary functions of the word counter
in the word/~it counter 88 is to count the number of
data words received sinc the last sync word was
detected by the sync word detector 74. When the count
- 5 reaches 63, a clock signal generated on line 94 sig-
nifies 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 detector 74 an overflow signal is gen-
erated in the interrupt controller 86 over line 92
causing the central processing uni~ 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 addi-
tion the CPU 20 will cause error flags to be set in
the buffer memory indicating that thls 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
42 and make it available to the display unit 22 even
when a sync word has not been detected so that
~2~ 72'
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valuable flight performance data is not lost just
because there may be an error in the sync wor~
contained in ~he 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 operatox
utilizing the keyboard 28 of the visual display unit.
When the appropriate ~light data parameters and units
have been selected, this infonmation is transmitted
by the visual display unit 22 to the central procescing
unit 20 which then causes the appropriate parameters
from the parameter data base 58 to be transmitted fr~m
the bulk memory 36 to the conversion tables 48 in the
high speed random access memory 34. After the initial-
ization 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 86 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 thls first subframe loaded in the buffer
memory 44 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 48
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 units
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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 ~he table of requested
parameter types with its own t:able of possible param-
eter types. When a match be~ween ~ables is found,
the system branchesto apply the unique conversion
process for the respective parameter type. Once the
raw data is converted ~o 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 initiaiization, 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 lexcluding BCD and discrete
parameters) defined in the parameter data base 58
can have, along with their unique scale factor and
3Q offset, a look-up table consisting of from 2 to 40
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, lineax inter-
polation into the look-up table is accomplished if
the table exists. The general flow of the conversion
process is as follows:
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raw data: offset and scale factor
intermediate result: look-up ta~le
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
2S Parameter type: Dl
(digital (signed) parameter from single data word)
(sign may be from a second data word)
IR = (+/-) Rl
IR - ~IR - offset) * scale factor
3Q EIJ - IR : table look-up
Parameter type; D2
(digital (signed) parameter from two data words)
(sign must be from second data word)
IR - (R2 * 4096~ + Rl
IR - (~/-) IR
EU = IR : table look-up
- 18 -
Parametex type: Xl
(discrete parameter from single data word)
EU = Rl
Paxameter type~ X2
(discrete parame~er from two data words)
EU = (R2 * 2) + Rl
Parameter type: G2
(GMT coded as a BCD value in two data words)
EU = HH:~M ~hours and minutes converted
from BCD to ASCII characters)
Parameter type: Hl
(linear tHamilton Standard) synchro from
single data word)
SD = Rl : linear synchro converslon
IR = (SD - offset) * scale factor
EU = IR : table look-up
Parameter type: H2
(].inear (Hamilton Standard) synchro from two
data words (altitude))
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 * 13.889))/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: Tl
(.non-linear (Teledyne) synchro from single
data word)
SD - Rl : non-linear synchro conversion
IR = (SD - offset) * scale factor
EU = IR : table look-up
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- 19 -
Parameter type: T2
(non linear (Teledyne) synchro from two-data
words ~altitude))
CD = ~2 : non-linear synchro conversion
FD = Rl : non-linear synchro conversion
if CD is greater than or equal to
350 degrees, then cr) = 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: Pl
(pneumatic parameter from single data word
(UFDR pneumatic airspeed))
IR = Rl * 0.002S : voltage
IR = (IR * scale factor) - offset : PSID
IR = IR * 144000 : PSFD * 1000
IR = IR : interpolated from pressure vs.
~irspeed table
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)
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
con~ersion algorithm for index 0 to 7:
,,~" a ~i~ 6 p t- S~a
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TT ~ R2/10.2 : transducer temperature
OT = ~ calibration factor inter~olated
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 tne
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
sraphical output of the flight data display system.
A front view of the visual display unit 22 is shcwn
with a representati~e exampie of a graphical display
of flight data projected on the CRT 26. In this
example four fligh~ 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 ai.r~peed; the single dot line 128 represents
- 21 -
magnetic heading and the solid line 130 represents
vertical acceleration. Values for the flight:para~-
eters are displayed on a segmented grid represented
by lines 132 and 134. Since the preferred visual
- 5 display unit 22 is a color graphics terminal, the
various portions of the display are produced in color
wherein for instance the altitude li~e 124 is yellow,
the airspeed line 126 is green, ~he 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 20
will provide one second worth of data from the converted
data bu~fer 52 at a tlme 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 key
board 2~ 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 key-
board 28. In the preferred embodiment, up to eight
different flight parameters along with two discretes
can be displayed at any one tLme. The operator addi-
tionally has the ability to control the operativecopy
recorder 14 throush the keyboard ~8 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 play-
back 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
~2~
- 22 -
parameter that he is interested in by utilizing the
controls on the keyboard 28.
