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MD41 Series ACU's
The Perfect Solution for a New Approach to Flying

The MD 41 combines navigation source switching to the primary CDI and HSI with key GPS selection functions in a standard ATI panel-mount unit only 4.65" deep. Up to seven separate relays and three switches are replaced by this single, compact unit, making installation simpler, faster and more economical. Lighted push buttons and easy-to-read annunciators make the MD 41 popular with pilots as well as technicians. Push buttons provide plenty of tactile feedback, ensuring safe, accurate operation, even in bumpy IFR conditions.

Pilots can fly with confidence, knowing that the MD 41 has been certified to TSO C129 standards, meeting the new FAA field approval requirements.

MD 41-1000 SERIES
Introducing Our Newest Development In Gps Control, "Slim Line Pro" ACU

For technicians, this compact, lightweight system greatly simplifies the installation of IFR approach-certified GPS units. For pilots, the MD41-1000 helps get the most out of their GPS, both en route and on approach.

Only 2.25" or 2.75" wide and 3.25" deep, the MD 41-1000 is available for either horizontal or vertical installation and is approved under TSO C129 to 55,000'. What's more, 24 user-defined relay poles are available in the remotely mounted switching unit. A complete installation kit with MIL-spec connectors further adds to installation flexibility and simplicity.

All annunciators and push buttons are integrated in a single unit while the relay are remotely mounted, enhancing safety and minimizing pilot workload. Push buttons are internally lighted and annunciators are photocell dimmed, making them easy to see in any lighting condition. Models are available for all approach-certified GPS systems. When it's time to plan your next GPS installation, take a close look at the MD 41-1000 ACU.
TSO C129 approved to newest FAA standards
Horizontal or vertical configuration
Proven daylight readability
Annunciators dim/brighten automatically
Push-button brightness controlled by instrument lighting rheostat
Connector/installation kit included
19-pole relays, gold-plated contacts
ILS frequency override selectable
Built-in annunciation self-test

NAV/GPS. Alternate action switch. Selects either NAV or GPS navigational information of HSI or CDI
GPS/APR. Momentary switch. Arm GPS approach mode
OBS/LEG. Alternate action switch. Selects either OBS or LEG mode
LAMP TEST. Momentary switch. Test annunciator lamps. How the
Pushing the NAV/GPS switch selects the navigation source (VOR/ILS/LOC or GPS) to be displayed on the HSI or CDI. Although it may be displayed on the GPS unit's built-in CDI, course information is also displayed on the panel-mounted HSI or CDI when executing an approach utilizing GPS navigational data.

Pushing the GPS/APR switch arms the GPS for the selected approach. Course guidance direct to the initial approach fix and automatic approach waypoint sequencing are then provided. The GPS receiver automatically switches from ARM to ACTV (Active) as the aircraft nears the final approach fix.

Pushing the OBS/LEG switch toggles between OBS and LEG. In OBS mode, the magnetic course to be flown "To" or "From" a waypoint is selected using the OBS knob on the HSI or CDI, similar to VOR navigation. In LEG mode, the GPS receiver automatically sequences between waypoints contained in the receiver's active flight plan.

The MSG annunciator is automatically lit when the GPS receiver initiates a message (airspace warnings, steep turns, etc.) MSG annunciation is automatically extinguished by the GPS receiver. The WPT annunciator flashes as the active waypoint in the GPS receiver is approached along the route of flight.

Vertical Mount for Flexibility
The MD 41 ACU is available in a convenient vertical mount for added installation flexibility. Also shown above are MD 41 versions for GPS systems not requiring the OBS/LEG or GPS/APR selector buttons.
TSO Approval TSO C129
Applicable Documents RTCA DO-160C, DO-208
Operating Temperature Range -20°C to +70°C
Humidity 95%
Altitude Range 0 to 35,000'
Vibration Cat M & N
Operational Shock Rigid mounting,
6 G operational.
15 G crash safety
Design All solid-state
Power Requirements MD 41-( ) 14 VDC: .065 AMPS
MD 41-( ) 28VDC: .40 AMPS
Relay Contact Current Rating: 2 AMPS DC
Available Relay
Poles (SPDT):
Mounting Panel-mount ATI
Width 3.5"
Height 1.350"
Depth 4.625"
Weight 0.75 lbs.