Midcontinent MD23-225 User manual

User Guide
For
MD23-225
Configurable Digital
Airspeed Indicator
powered by
Rev
Date
Detail
Approved
1
12/09/2021
Initial release.
BAW
This manual provides information intended for use by persons who, in accordance with current
regulatory requirements, are qualified to install this equipment. It is a supplement to the MD23
Installation Manual and Operating Instructions, p/n 9019161.
If further information is required, please contact Mid-Continent Instruments and Avionics.
Mid-Continent Instruments and Avionics Mid-Continent Instrument Co., Inc.
dba Mid-Continent Instruments and Avionics
User Guide UG225 9400 E. 34th Street N.
Revision 1 Wichita, KS 67226 USA
ph [phone]
www mcico.com

MD23-225
User Guide
Mid-Continent Instruments and Avionics 2 User Guide UG225, Revision 1
December 9, 2021
1.1 INTRODUCTION
The model MD23-225 Digital Airspeed Indicator is a standard 2-inch (2-¼”) panel-mounted
instrument that can be configured to display several ranges and range markings for indicated
airspeed. Based on Mid-Continent Instruments and Avionics patented FLEXTM Custom Function
Display, this FAA and EASA TSO-approved instrument bring a highly capable and modern
addition to the cockpit to display required information and provide useful related functions.
This User Guide is a supplement to the Installation Manual and Operating Instructions (IM),
MCIA part number 9019161. The IM contains all information associated with the standard
product, including installation procedures, product specifications, operating instructions,
certification data, and maintenance requirements. This User Guide provides additional
information associated with the specific features of the configurable digital airspeed indicator. It
addresses product identification, electrical pinout, initial configuration setup, and in-flight user
operation.
1.2 PRODUCT IDENTIFICATION
Each MD23 is comprised of certified hardware and certified software. Within the context of the
certified software is a set of data items that can configure and customize the behavior of the unit.
This set of data is referred to as a Custom Instrument Definition, or a CID file. The CID file for
this instrument is pre-loaded and may be available for future updates via a standard USB flash
drive through the programming port on the rear of the unit.
A unique CID number has been assigned specifically to this application. The CID is identified by
its two-digit number and an alphabetic character representing the CID version, starting with “A”.
The identification of the hardware, software, and CID configurations are listed below. Both the
software version and the CID can be viewed on the Introduction Screen during the first few
seconds of applying power to the unit. This information can also be accessed on the Info page of
the Options Menu during Flight Mode.
PRODUCT FUNCTION
The Configurable Digital Airspeed Indicator primarily provides indicated airspeed up to 500
knots. Airspeed is numerically presented as a scrolling value in a central window (known as a
‘counter drum’) with 1 unit resolution. A single pointer also provides visual analog representation
with selectable maximum ranges of 160, 200, 300, 400, or 500. Colored range marking arcs can
be configured to represent various speed thresholds for a given installation. Airspeed units are
available in knots or miles per hour.
Other features include a dynamic MMO, or barber pole, function, a Mach number display, and
optional display of external data such as true air speed (TAS) and ground speed (GS). The
instrument can also provide airspeed and Mach number as a digital output to other equipment.
Unit Versions
Hardware Part Number
Software Version
CID
6420023-2
1.0.2, or later
25A, or later

MD23-225
User Guide
Mid-Continent Instruments and Avionics 3 User Guide UG225, Revision 1
December 9, 2021
2.1 CONNECTOR PINOUT
For standard pre-installation and installation instructions, including location, cable harness
assembly, pneumatic inputs (if applicable), mounting, and others, please refer to the IM.
Pinout identification specific to this CID is listed in the table below. A brief description is provided.
Further definition of the inputs and outputs should be documented in the technical requirements
and/or statement of work and are not provided within this User Guide.
Connector Pinout
Pin
Description
Function
1
Ground
Power return; connect to a/c ground
2
ARINC Out (A)
Labels 205, 206
3
ARINC Out (B)
(paired with pin 2)
4
Dimmer Input
5, 14, or 28VDC input (if used)
5
ARINC In (A)
Labels 210, 312
6
Reserved
7
Reserved
8
Reserved
9
Reserved
10
Reserved
11
Reserved
12
Reserved
13
Reserved
14
ARINC In (B)
(paired with pin 5)
15
Reserved
16
Reserved
17
Reserved
18
Reserved
19
Power Input
+10-32VDC
20
Reserved
21
Reserved
22
Reserved
23
Reserved
24
Reserved
25
Reserved
26
Reserved
Table 1 Unit Connector Pin Identification
Pneumatic Ports
Port
Description
Function
S
Static / Absolute
External Static Pressure
P
Pitot / Differential
External Pitot Pressure

MD23-225
User Guide
Mid-Continent Instruments and Avionics 4 User Guide UG225, Revision 1
December 9, 2021
3.1 CONFIGURATION AND SETUP
Enter Configuration Mode by pressing and holding the Control
Knob while applying power to the unit. For configuration and
setup of standard unit functions, including dimming control
options and dimming curve definition, please refer to the IM.
Configuration settings specific to this unit are found within the
User Configuration menu option. The User Configuration items
include the following functions:
3.1.1. MAX SPEED
The Max Speed configuration item sets the range of the
airspeed indicator. Options available are 160, 200, 300,
400, or 500.
Turn the Control Knob to highlight the preferred range and
press to select it. The cursor will return to the User
Configuration options in the menu list and the selected
option will be shown in gray to the right.
3.1.2. CONFIGURE ARCS
The Configure Arcs function is used to set up unique range
markings for each particular installation. Refer to the
aircraft’s Pilot Operating Handbook (POH) for appropriate
airspeed markings. For each element/arc, press the Control
Knob to select the item, turn the Control Knob to select a
half arc, full arc, or radial, then press the Control Knob again
and select a color. Once selected, the screen will show the
dial and allow the user to turn the knob to the beginning
position (LO) of the arc or radial, indicated with a blinking
magenta marker. The numeric counter drum will also show
the exact value. Once determined, press the Control Knob
and repeat the process to define the end position of the arc
(HI) (if applicable). Pressing the Control Knob again will
return back to the Configure Arcs table. Repeat the process
for all arcs and radials.
NOTE: The arcs that are at the top of the list have priority
and are displayed ‘on top’. If there is any overlap of arcs,
those defined further down in the list will be placed under
those above it.

MD23-225
User Guide
Mid-Continent Instruments and Avionics 5 User Guide UG225, Revision 1
December 9, 2021
3.1.3. CALIBRATE PITOT
Use the Calibrate Pitot process if the displayed airspeed
does not match a known airspeed reference. When
selected, the Calibrate Pitot option opens a new page. Allow
the unit five to ten (5-10) seconds to settle and display the
currently reported airspeed. The airspeed will be shown in
the units that are currently configured.
Turn the Control Knob until the airspeed value matches the
known external reference (note: zero airspeed is an
acceptable reference value). Pressing the Control Knob will
confirm the calibration and exit the page back to the User Configuration Menu.
3.1.4. AIRSPEED UNITS
Within the User Configuration Menu, the Airspeed Units can
be set without leaving the page. By selecting the Airspeed
Units option, the units to the right become active and
additional options are displayed. The MD23 can be set to
display airspeed in either Knots or MPH (miles per hour).
Turn the Control Knob to highlight the preferred units and
press to select it. The cursor will return to the Airspeed Units
option in the menu list and the selected option will be shown
in gray to the right.
3.1.5. SET MMO
To set the maximum Mach operating speed, use the SET
MMO feature in the User Configuration menu. By selecting
the appropriate MMO Mach number on this page, it will
control the behavior of the barber pole on the dial, indicating
the effective speed limit at the given altitude and airspeed
conditions. Turn the value down to zero to turn the MMO
feature OFF (which will be displayed as OFF in white).
Press the Control Knob to complete the entry and return to
the User Configuration Menu.
3.1.6. EXIT
Highlighting and selecting the Exit menu item will close the User Configuration Menu and
return to the Configuration Menu. Exiting the Configuration Menu will reboot the unit into
Flight Mode.

MD23-225
User Guide
Mid-Continent Instruments and Avionics 6 User Guide UG225, Revision 1
December 9, 2021
4.1 OPERATION
For operation of standard unit functions, including the Options Menu, manual brightness control,
Info page, and others, please refer to the IM.
4.1.1. PRIMARY DISPLAY PRESENTATION
In Flight Mode, the display is presented as shown in the example figures below.
Power on screen Normal Operation
(example) (example)
Primary Function elements are defined as follows:
•Dial: Numbers from 0 to max indicated airspeed, with numeric major grads and sub-
divided graduations between. No airspeed is indicated between zero and the minimum
airspeed value shown on the dial grads.
•Pointer: Rotates clockwise with increasing airspeed, counter-clockwise with decreasing
airspeed. The unit cannot display negative airspeed.
•Counter Drum window: Displays the airspeed as a numeric value. The value is displayed
in an expanded window with rolling numbers representing every 1 unit. The tens or
hundreds digits will change with a similar rolling action at each increment. Invalid
airspeed will be represented with red dashes (- - -). The airspeed units, as selected in
the Configuration Mode, is displayed below the window.
4.1.2. SECONDARY DISPLAY PRESENTATION
Secondary Function elements are defined as follows. Further
details about each secondary function can be found in 4.1.3.
•Mach Number: displayed in the lower right corner.
•Ground Speed (GS): displayed in the upper left corner.
•True Air Speed (TAS): displayed in the lower left corner.

MD23-225
User Guide
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December 9, 2021
4.1.3. USER OPTIONS
Pressing and holding the Control Knob for three (3) seconds
will activate the Options Menu. The manual brightness
adjustment and info page are described in the IM. The Options
Menu or User Options items will close and return to the active
display after ten (10) seconds if no knob activity is recorded.
When highlighted and selected, the User Options item will open
a new page and display the available options available to the
user during Flight Mode. The User Options menu is where the
Secondary Functions can be turned on or off. The list of
features are provided in 4.1.2 and shown in the image.
Mach number can be turned on or off and is available based on standard pitot and static
inputs. Mach number will also be output via ARINC 429 on label 205.
For True Airspeed (TAS) and Ground Speed (GS), an external ARINC 429 Input must be
provided for labels 210 and 312, respectively, in order to view this information. If these
features are turned on without an external input, the values will be shown as “- - -“.
Highlight and select Exit to return to the Options Menu or simply wait ten (10) seconds and
the unit will return to the active Flight Mode display.
5.1 CONFORMANCE
For standard conformance items such as qualification levels and software updates, please refer
to the IM.
5.1.1 INSTRUCTIONS FOR CONTINUED AIRWORTHINESS
For this application, the MD23 is configured to accept and display data associated with a
static and pitot pressure source. Some aviation regulations may apply to inspect and test for
accuracy on a regular basis. (for example, 14 CFR §91.411 for altimeters) Please identify
and/or refer to the appropriate maintenance procedures for your aircraft in the pilot operating
handbook or flight manual supplement.
5.1.2 COMPONENT MAINTENANCE AND REPAIR
No periodic scheduled maintenance or calibration is necessary for continued airworthiness of
the MD23 Custom Function Display, unless specified in the aircraft maintenance procedures,
as referenced above in 5.1.1.
The unit display can be cleaned using a lint-free cloth moistened with water. No chemicals
should be used to clean the display.
If the unit fails to perform to specifications, the unit must be removed and serviced by Mid-
Continent Instruments and Avionics or their authorized designee. Other than software version
updates or in-field calibration, there are no repairable parts or processes available to be
performed in the field.