Midcontinent MD41 Series Technical Document

INSTALLATION MANUAL AND
OPERATING INSTRUCTIONS
MD41-( ) Series GPS Annunciation Control Unit
For Garmin GNS 480 and Garmin AT CNX80 VHF
Communication and Navigation Management System
MD41-1748 28vdc Horizontal Mount
MD41-1748(5V) 28vdc Horizontal Mount with 5 volt lighting
MD41-1758 28vdc Vertical Mount (shown on page 11)
MD41-1758(5V) 28vdc Vertical Mount with 5 volt lighting
MD41-1744 14vdc Horizontal Mount
MD41-1754 14vdc Vertical Mount (shown on page 11)
Mid-Continent Instruments and Avionics Manual Number 9015669
9400 E. 34th Street N., Wichita, KS 67226 USA REV. 1 August 17, 2004
Phone [phone] Fax [phone]

REV. 1 August 17, 2004 2
Revision Detail
Rev. Date Detail
N/R 06/05/03 Complete issue
1 08/17/04 Added Garmin GNS 480

REV. 1 August 17, 2004 3
TABLE OF CONTENTS
SECTION 1 GENERAL DESCRIPTION
1.1 INTRODUCTION
1.2 SPECIFICATIONS, TECHNICAL
1.2.1 PHYSICAL CHARACTERISTICS
1.2.2 ENVIRONMENTAL CHARACTERISTICS
1.2.3 SPECIFICATIONS, ELECTRICAL
1.2.4 FRONT PANEL CONTROLS AND ANNUNCIATIONS
1.2.4.1 CONTROLS
1.2.4.2 ANNUNCIATIONS
1.2.5 INTERFACE
1.2.6 EQUIPMENT LIMITATIONS
1.2.7 MAJOR COMPONENTS
SECTION 2 INSTALLATION CONSIDERATIONS
2.1 COOLING
2.2 EQUIPMENT LOCATION
2.3 ROUTING OF CABLES
SECTION 3 INSTALLATION PROCEDURE
3.1 GENERAL INFORMATION
3.2 UNPACKING AND INSPECTING
3.3 MOUNTING THE MD41-( )
3.4 INSTALLATION LIMITATIONS
SECTION 4 POST INSTALLATION CHECKOUT
4.1 PRE-INSTALLATION TEST
4.2 OPERATING INSTRUCTIONS
4.3 CONTINUED AIRWORTHINESS
FIGURE N0. LIST OF ILLUSTRATIONS
3.1 SCHEMATIC PINOUT, 25 PIN DSUB
3.2 OUTLINE DRAWING
3.3 WIRING DIAGRAM, MD41-1744/1754 (14Volt),
MD41-1748/1758/1748(5V)/1758(5V) (28volt)
APPENDIX
ENVIRONMENTAL QUALIFICATION FORM

REV. 1 August 17, 2004 4
SECTION 1 GENERAL DESCRIPTION
1.1 INTRODUCTION
The MD41-( ) is a compact, self -contained GPS Annunciation and Control unit. It meets all
requirements for external (remote) mode selection and status annunciation for the Garmin GNS
480 VHF and Garmin AT CNX80 Communication, Navigation Management System.
Features include dual 20,000 hour lamps used for all annunciations, internally lighted
selection switches and automatic photocell dimming. An external annunciation dimming
adjustment is provided for balancing low level light conditions.
1.2 SPECIFICATIONS, TECHNICAL
1.2.1 PHYSICAL CHARACTERISTICS
Mounting: Panel
Width: 3.25 Inches
Height: .80 Inches
Depth: 3.20 Inches
Weight: 0.50 lbs.
1.2.2 ENVIRONMENTAL CHARACTERISTICS
TSO Compliance: TSO C129
Applicable Documents: RTCA DO-160D, DO-208
Operating Temperature Range: -55C to +70C
Humidity: 95% Non-Condensing
Altitude Range: 0 to 55,000 ft.
Vibration: Cat. U and S
Operational Shock: Rigid Mounting, 6 G Operational
15GCrashSafety
1.2.3 SPECIFICATIONS, ELECTRICAL
Design AllSolidState
MD41-1744/1754 (14VDC) 0.40 Amps
MD41-1748/1758 (28VDC) 0.30 Amps
MD41-1748(5V)/1758(5V) (28DC) 0.30 Amps

REV. 1 August 17, 2004 5
1.2.4 FRONT PANEL CONTROLS AND ANNUNCIATIONS
1.2.4.1 CONTROLS
CDI Momentary action switch, when pressed, will select VOR/ILS
(NAV) or GPS presentation on HSI/CDI.
SUSP Momentary action switch, when pressed, will suspend automatic
waypoint sequencing in the active flight plan.
1.2.4.2 ANNUNCIATIONS
NAV VOR or ILS information presented on the HSI or CDI.
GPS GPS information presented on the HSI or CDI.
MSG Flashing indicates new status message(s) available
WPT Flashing indicates aircraft is 10 to 20 seconds of reaching the
turning point for course change. Steady indicates aircraft in
course change turn.
SUSP Automatic sequencing of waypoints has been suspended.
LOI Loss of Integrity. WAAS/GPS detects a position error or unable
to calculate integrity of position.
PTK Parallel track mode is selected.
ALT Altitude Alert. Indicates the estimated altitude is lower than the
alarm limits.
TERM On indicates aircraft is navigating within 30 miles of the
departure or arrival airport or on a SID or STAR.
APR On indicates the approach is active.
1.2.5 INTERFACE
CDI (select)
J1 Pin 4 Provides a momentary low to the GNS 480 (CNX80)
SUSP (select)
J1 Pin 12 Provides a momentary logic low to the GNS 480 (CNX80) when Suspend is selected.
NAV annunciation
J1 Pin 2 Receives ground from GNS 480 (CNX80) when in VOR/ILS mode.
NAV annunciation
output, J1 Pin 16. Logic low when NAV annunciation is turned on. May be connected to MD200 NAV annunciation input.
GPS annunciation
J1 Pin 1 Receives ground from GNS 480 (CNX80) when in GPS mode.

REV. 1 August 17, 2004 6
1.2.5 INTERFACE (cont.)
GPS annunciation
output, J1 pin 14 Logic low when GPS annunciation is turned on. May be connected to MD200 GPS annunciation input.
SUSP annunciation
J1 Pin 24 Requires a logic low to annunciate
TERM annunciation
J1 Pin 15 Requires a logic low to annunciate
APPR annunciation
J1 Pin 3 Requires a logic low to annunciate
WPT annunciation
J1 Pin 8 Requires a logic low to annunciate
MSG annunciation
J1 Pin 6 Requires a logic low to annunciate
PTK annunciation
J1 Pin 11 Requires a logic low to annunciate
ALT annunciation
J1 Pin 10 Requires a logic low to annunciate
LOI annunciation
J1 Pin 9 Requires a logic low to annunciate
Lamp Test
J1 Pin 7 Receives ground from remote test switch to light all annunciations. (optional connection)
1.2.6 EQUIPMENT LIMITATIONS
The MD41-( ) series control units contain specific dash numbers to be used with various GPS
receivers or Navigation Management Systems. The installer must match the correct controller part
number with the system being installed.
The conditions and tests required for TSO approval of this article are minimum performance
standards. It is the responsibility of those desiring to install this article either on or within a
specific type or class of aircraft to determine that the aircraft installation conditions are within
the TSO standards. The article may be installed only if further evaluation by the applicant
documents an acceptable installation and is approved by the Administrator.

REV. 1 August 17, 2004 7
The MD41-1744/1754/1748/1758/1748(5V)/1758(5V) is TSO’D and certified for use with the
Garmin GNS 480 and Garmin AT CNX80 system. Any attempts to install the listed units in an
installation other than these two systems is prohibited. This will void the TSO.
NOTE: If the MD41-( ) is disconnected or removed from the aircraft, there will
be no effect in the operation of the GNS 480 or CNX80.
1.2.7 MAJOR COMPONENTS
This system is comprised of one major component, the MD41-174X/175X series GPS
Annunciation Control Unit.

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SECTION 2 INSTALLATION CONSIDERATIONS
2.1 COOLING
No direct cooling is required. As with any electronic equipment, overall reliability may be
increased if the MD41-( ) is not located near any high heat source or crowded next to other
equipment. Means of providing a gentle air flow will be a plus.
2.2 EQUIPMENT LOCATION
The MD41-( ) must be mounted as close to the pilot’s field of view as possible. The preferable
location is near the HSI/CDI that will be displaying the GPS/NAV information. The unit depth,
with connector attached, must also be taken into consideration. Note: Unlike previous versions of
the MD41 Annunciation Control Units (ACU), the transfer relays are not required as all switching
between GPS, VOR and ILS is handled by the GNS 480 or CNX80.This has allowed a for a
smaller size ACU which now provides more options for panel mounting.
2.3 ROUTING OF CABLES
Care must be taken not to bundle the MD41-( ) logic and low level signal lines with any high
energy sources. Examples of these sources include 400 HZ AC, Comm, DME, HF and
transponder transmitter coax. Always use shielded wire when shown on the installation print.
Avoid sharp bends in cabling and routing near aircraft control cables.

REV. 1 August 17, 2004 9
SECTION 3 INSTALLATION PROCEDURES
3.1 GENERAL INFORMATION
This section contains interconnect diagrams, mounting dimensions and other information
pertaining to the installation of the MD41-( ). After installation of cabling and before installation
of the equipment, ensure that power is applied only to the pins specified in the interconnect
diagram.
3.2 UNPACKING AND INSPECTING EQUIPMENT
When unpacking equipment, make a visual inspection for evidence of damage incurred during
shipment. The following parts should be included:
1. MD41-1744 (14volt) or MD41-1748 (28 volt) Horiz. Mount
MD41-1754 (14volt) or MD41-1758 (28volt) Vert. Mount
MD41-1748(5V) (28volt) 5 volt button lighting Horiz. Mount
MD41-1758(5V) (28volt) 5 volt button lighting Vert. Mount
2. J1 Connector Kit (25 pin). MCI PN 7014517
3. Installation Manual. MCI PN 9015669
3.3 MOUNTING THE MD41-( )
Plan a location in the aircraft for the MD41-( ) to be mounted as close to the pilot’s field of view
as possible. The preferable location is near the HSI/CDI that will be displaying the navigation
information. Avoid mounting close to heater vents or other high heat sources. Allow a clearance
of at least 3 inches from back of unit for plug removal.
The indicator is secured in place behind the panel since it is designed for rear mount only. Make a
panel cutout as shown in Figure 3-2. Secure the indicator in place with two 4-40 x 3/8 flat head
phillips screws.
3.4 INSTALLATION LIMITATIONS
Wire the aircraft harness according to figure 3-3. Use at least 24 AWG wire for all connections.
Avoid sharp bends and routing cable near high energy sources. Care must be taken to tie the
harness away from aircraft controls and cables. Normal installation techniques should be applied.
Also see equipment limitations, section 1.2.6.

REV. 1 August 17, 2004 10
REAR VIEW OF J1 CONNECTOR
J1
PIN NO.
1 ---------------------------- GPS ANNUNCIATION
2 ---------------------------- NAV ANNNCIATION
3 ---------------------------- APPR ANNUNCIATION
4 ---------------------------- CDI SOURCE SELECT (momentary logic low sent to receiver)
5 ---------------------------- DIMMER IN (from aircraft dimming bus for push-button lighting)
6 ---------------------------- MSG ANNUNCIATION
7 ---------------------------- LAMP TEST (receives ground from remote test switch)(optional conn.)
8 ---------------------------- WPT ANNUNCIATION
9 ---------------------------- LOI ANNUNCIATION
10 -------------------------- ALT ANNUNCIATION
11 -------------------------- PTK ANNUNCIATION
12 -------------------------- SUSP MODE SELECT (momentary logic low sent to the receiver)
13 -------------------------- 14 or 28 VDC UNIT POWER (depends on dash number)
14 -------------------------- GPS ANNUNCIATION OUTPUT
15 -------------------------- TERM ANNUNCIATION
16 -------------------------- NAV ANNUNCIATION OUTPUT
17 -------------------------- SPARE
18 -------------------------- SPARE
19 -------------------------- SPARE
20 -------------------------- SPARE
21 -------------------------- SPARE
22 -------------------------- SPARE
23 -------------------------- SPARE
24 -------------------------- SUSP ANNUNCIATION
25 -------------------------- POWER GROUND
FIGURE 3-1 SCHEMATIC PINOUT, 25 PIN DSUB