Page 1
TMA44 Audio Panel
Installation Manual
01849-00-AB
7 November 2017
Trig Avionics Limited
Heriot Watt Research Park
Riccarton, Edinburgh
EH14 4AP
Scotland, UK
Copyright Trig Avionics Limited, 2017
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CONTENTS
1.
PREFACE ............................................................................................... 1
1.1 PURPOSE ........................................................................................... 1
1.2 SCOPE ............................................................................................... 1
1.3 CHANGES FROM PREVIOUS ISSUE ...................................................... 1
1.4 DOCUMENT CROSS-REFERENCES ...................................................... 1
2. INTRODUCTION ................................................................................. 2
2.1 EQUIPMENT DESCRIPTION ................................................................. 2
2.2 TSO HOLDER .................................................................................... 2
3. TECHNICAL SPECIFICATIONS ...................................................... 3
3.1 PHYSICAL SPECIFICATIONS ............................................................... 5
3.2 APPROVAL BASIS .............................................................................. 5
3.3 LICENSE REQUIREMENTS .................................................................. 5
4. UNIT AND ACCESSORIES SUPPLIED ............................................ 6
4.1 EQUIPMENT SUPPLIED ....................................................................... 6
4.2 INSTALLATION KIT ........................................................................... 6
4.3 REQUIRED ITEMS .............................................................................. 7
5. INSTALLATION ................................................................................... 8
5.1 UNPACKING AND PRELIMINARY INSPECTION .................................... 8
5.2 EQUIPMENT INSTALLATION PROCEDURES ......................................... 8
5.2.1 Cooling Requirements .............................................................. 8
5.2.2 Mounting Requirements ........................................................... 9
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5.2.3 Mounting Rack Installation ...................................................... 9
5.2.4 Audio Panel Tray and Connector Assembly ............................ 9
5.3 CABLE HARNESS WIRING ............................................................... 10
5.3.1 Noise ...................................................................................... 10
5.3.2 Entertainment Input (J1 pin 9 & 25) ...................................... 11
5.3.3 TMA44 Pin assignments ........................................................ 13
5.3.4 External Push-to-Talk (J1 pin 32 pilot, J1 pin 31 co-pilot) ... 14
5.3.5 Transmit Interlock .................................................................. 14
5.3.6 Power (J1 pin 43) ................................................................... 14
5.3.7 "Swap" Mode (J1 pin 11) ....................................................... 15
5.3.8 Backlighting (J1 pin 41) ......................................................... 15
5.3.9 Backlight Voltage Adjustment ................................................ 15
5.3.10 Middle Marker Sense (J1 pin 27 & 28) .................................. 17
5.3.11 Unswitched Inputs (J1 pin 7, 22 & 24) .................................. 17
5.3.12 Intercom ................................................................................. 17
5.4 ADJUSTMENTS ................................................................................ 18
5.5 MARKER ANTENNA INSTALLATION ................................................ 19
5.6 COMMUNICATIONS ANTENNA INSTALLATION NOTES ..................... 19
5.7 UNIT INSTALLATION ....................................................................... 19
6. POST INSTALLATION CHECKOUT ............................................. 20
6.1 REQUIRED TEST EQUIPMENT .......................................................... 20
6.2 POWER TEST ................................................................................... 20
6.3 MARKER CHECKOUT ....................................................................... 21
7. FINAL INSPECTION ......................................................................... 22
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8. NORMAL OPERATION .................................................................... 23
8.1 FRONT PANEL ................................................................................. 23
8.2 POWER ON AND FAIL-SAFE OPERATION ......................................... 23
8.3 TRANSMITTER SELECTION .............................................................. 23
8.4 RECEIVER SELECTION ..................................................................... 24
8.5 NAVIGATION AUDIO SELECTION ..................................................... 24
8.6 COCKPIT SPEAKER .......................................................................... 24
8.7 SWAP MODE ................................................................................... 24
8.8 SPLIT MODE .................................................................................... 25
8.9 INTERCOM VOLUME ........................................................................ 25
8.10 INTERCOM SQUELCH ....................................................................... 25
8.11 INTERCOM MODES .......................................................................... 26
8.12 INTERCOM MODE TABLE ................................................................ 27
8.13 MUSIC INPUTS ................................................................................ 27
8.14 MUSIC MUTING .............................................................................. 27
8.15 MARKER BEACON RECEIVER .......................................................... 28
9. CONTINUED AIRWORTHINESS ................................................... 29
9.1 CLEANING THE FRONT PANEL ......................................................... 29
10. LIMITED WARRANTY ................................................................. 30
11. ENVIRONMENTAL QUALIFICATION FORM ........................ 31
APPENDIX A EXTERNAL PTT HOOK UP ..................................... 33
PUSH TO TALK MODIFICATIONS ................................................................. 33
Procedures for David Clark PTT ........................................................... 34
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Procedures for Telex PT-200 ................................................................. 34
Procedures for Telex PT-300 ................................................................. 34
APPENDIX B INSTALLATION DRAWINGS .................................. 35
APPENDIX C WIRING/INTERCONNECT ...................................... 37
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1. Preface
1.1 Purpose
This manual describes the physical and electrical characteristics and the
installation requirements for a TMA44 Audio Panel.
1.2 Scope
This manual applies to the installation of the TMA44 Audio Panel.
1.3 Changes from Previous Issue
No text changes – reformatted for A5.
1.4 Document Cross-References
01848-00 TMA44 Audio Panel Operating Manual
TSO C35d Airborne Radio Marker Receiving Equipment FAA
ETSO 2C35d Radio Marker Receiving Equipment EASA
TSO C50c Audio Selector Panels and Amplifiers FAA
ETSO C50c Audio Selector Panels and Amplifiers EASA
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2. Introduction
2.1 Equipment Description
The TMA44 is a state of the art audio isolation amplifier and audio selector
that contains a voice activated (VOX) intercom system. It can switch up two
transceivers (Com 1, Com 2) and six receivers (Nav 1, Nav 2, ADF, DME,
MKR and AUX). In addition, there are two unswitched inputs, for priority
audio sources such as TAWS or altimeter warning. Push buttons select the
receiver audio sources provided to the headphones. A speaker button allows
the user to listen to the receiver(s) selected on the cabin speaker. Except for
the unswitched inputs, all speaker audio is muted during transmit. Push
buttons select one of the transceivers for the pilot and co-pilot position in
transmit. In "Split Mode" the TMA44 allows the pilot and co-pilot to operate
different transmitters independently.
A fail-safe mode connects the pilot headphone and microphone to Com 1 and
unswitched input 1 if power is removed for any reason, or if the audio panel is
turned off by pushing the volume control.
A four-station voice activated (VOX) intercom is included in the TMA44.
Pilot isolate and crew modes, two mono music inputs with "Soft Mute" and
transmit indications. Intercom control is through front panel mounted knobs.
Dual concentric knobs control intercom volume and intercom squelch.
A 3-light Marker Beacon receiver is integral to the TMA44. This provides the
necessary Marker Beacon light and audio indications necessary for an
Instrument Landing System (ILS) approach.
2.2 TSO Holder
The TSO holder and manufacturer of the TMA44 is PS Engineering, Lenoir
City, TN, USA.
US patents no. 5,903,227 and 6,160,496 apply.
SoftMute is a trademark of PS Engineering.
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3. Technical Specifications
Specification Characteristics
Compliance Marker Beacon: TSO C35d, Class A, ETSO
2C35d
Audio Selector/Intercom: TSO C50d, Class A,
ETSO C50c
Applicable documents RTCA DO-160B, RTCA DO-170 and RTCA
DO-143
Power Requirements Voltage: 14 or 28 VDC*
Maximum current 1 amp (externally protected
by a 2 amp circuit breaker). Typical operating
current 350 mA (speaker off), 600 mA
(speaker on).
*28 VDC requires 15W dropping resistor
(included)
Altitude Up to 50,000 feet in a non-pressurised area of
the cockpit
Operating Temperature -20°C to +55°C
Storage Temperature -40°C to +85°C
Input impedance
510
Input Isolation -70 dB (min.)
Speaker Muting -60 dB (min.)
Speaker Output (into 4 )
3 watts (min.) with no clipping
Switched Receiver Inputs 8 (Com 1, Com 2, Nav 1, Nav 2, ADF, DME,
MKR, AUX)
Unswitched Inputs 2
Transmitter Selections 3; Com 1, Com 2, Com 1/2
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Speaker Impedance
4
Headphone Impedance
150 - 1000
Headphone Output 45 mW each headset with no clipping
Microphone Impedance
150 - 600
Intercom Positions 4 places (monaural)
Music Inputs 2
Music Muting
Distortion
>50 dB "Soft Mute" when Radio or intercom
active
<1% THD@ 45 mW into 150
Mic Freq. Response, ±3 dB 350 Hz - 6000 Hz
Music Freq. Response, ±3 dB 200 Hz - 15 kHz
Marker Beacon Receiver
Frequency
75 MHz Crystal Controlled
Marker Beacon Receiver
Sensitivity
Low: 450 µV (Hard) Factory adjusted to
1400µV (Soft)
High: 160 µV (Hard) Factory adjusted to
150µV (Soft)
Marker Beacon Receiver
Selectivity
-6 dB at 110 kHz, -40 dB at 120 kHz
External Lamp Output 7.0 (+/- 4) VDC positive when active, max.
current 125 mA
MM Sense Active high (4.7 VDC +/- 0.5V) during
Middle Marker acquisition, for autopilot use
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3.1 Physical Specifications
Specification Characteristics
Height 33 mm (1.30”)
Width 159 mm (6.25”)
Depth 173 mm (6.8”)
Weight 0.68 kg (1.5lbs)
3.2 Approval basis
The TMA44 is FAA authorised under TSO C50c (Audio Amplifiers) and TSO
C35d (Marker Beacon Receivers).
The TMA44 is EASA authorised under ETSO C50c and ETSO 2C35d, ref
EASA.IM.21O.10028565
All systems comply with RTCA DO-143, DO-160B, DO-170, and EUROCAE
1/WG7/70.
TSO Holder and Manufacturer PS Engineering, Lenoir City TN USA
Operation is subject to the following conditions:
1. This device may not cause harmful interference.
2. This device must accept any interference received, including
interference that may cause undesired operation
3.3 License Requirements
None
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4. Unit and Accessories supplied
4.1 Equipment Supplied
Unit Description Qty Part Number
TMA44 Audio Panel 1 01861-00-01
TMA44 Installation kit 1 250-604-0000
TMA44 Mounting Tray 1 430-890-0040
TMA44 Pilots Operating Handbook 1 01848-00
TMA44 Installation Manual 1 01849-00
4.2 Installation Kit
The TMA44 installation kit includes the following items:
Unit Description Qty Part Number
Cable Clamp 1 625-001-0002
6-32 Clip Nut 6 475-630-0002
6-32 x ½” Phillips flat head screw 6 475-632-0012
4-40 x 7/16” Phillips pan head screw, nylon patch 4 475-440-0007
4-40 x 3/8” Phillips truss head screw, nylon patch 2 475-440-1038
4-40 x ¼” Phillips pan head screw, lock washer 2 475-440-0001
Solder lug terminal 2 475-009-0001
TMA44 backplate 1 430-890-0050
DB44 metal backshell 1 625-025-2465
Cast DB44 retaining block 1 431-891-0100
44-pin connector kit 1 120-891-2045
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Unit Description Qty Part Number
15Ω, 15W dropping resistor 1 701-015-1501
4.3 Required Items
Additional items you will require, but which are not in the TMA44 package,
include:
Speaker, 4
Headphones, mono, up to 4 as required
Microphones, up to 4 as required
Marker Antenna (75 MHz, VSWR <1:1.5, as appropriate)
Interconnect Wiring
Headphone Jacks (Up to 4 as required)
Microphone Jacks (Up to 4 as required)
Circuit Breaker, 2 amp
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5. Installation
This section provides detailed installation and interconnect instructions for the
TMA44 Audio Panel.
Please read this manual carefully before beginning any installation to prevent
damage and post installation problems. Installation of this equipment requires
special tools and knowledge.
5.1 Unpacking and Preliminary Inspection
Use care when unpacking the equipment. Inspect the units and parts supplied
for visible signs of shipping damage. Examine the unit for loose or broken
buttons, bent knobs, etc. Verify the correct quantity of components supplied
with the list in Section 4. If any claim is to be made, save the shipping material
and contact the freight carrier. Do NOT return units damaged in shipping to
Trig. If the unit or accessories shows any sign of external shipping damage,
contact Trig to arrange for a replacement. Under no circumstances attempt to
install a damaged unit in an aircraft. Equipment returned to Trig for any other
reason should be shipped in the original Trig packaging, or other UPS
approved packaging.
5.2 Equipment Installation Procedures
5.2.1 Cooling Requirements
Forced-air cooling of the TMA44 is not required. However, the unit should be
kept away from heat producing sources such as defrost or heater ducts,
dropping resistors or heat producing avionics without adequate cooling air
provided.
If the TMA44 is installed in a 28 VDC aircraft system, a 15 , 15 watt
dropping resistor (p/n 701-015-1501) should be installed. Failure to do so will
generate unnecessary heat inside the unit and may void Trig's warranty.
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5.2.2 Mounting Requirements
The TMA44 must be rigidly mounted to the instrument panel of the aircraft
structure and within view and reach of the pilot position(s). Installation must
comply with FAA Advisory Circular AC 43.13-2B. The unit may be mounted
in any area where adequate clearance for the unit and associated wiring bundle
exist.
5.2.3 Mounting Rack Installation
Remove the unit from the mounting tray unscrewing the 3/32-inch hex-head
screw that is in the centre of the unit. The hex-head screw is the lower
opening. Carefully slide the unit free of the tray. Set the unit aside in a safe
location until needed. Install the tray using six flat head Phillips 6-32 x ½inch screws, P/N 475-632-0012 and 6-32 clip nut, P/N 475-630-0002. The
audio selector panel must be supported at front and rear of the mounting tray.
5.2.4 Audio Panel Tray and Connector Assembly
The rack connectors mate with one 44-pin connector in the TMA44. The
connector is a sub-miniature crimp-type, and require the use a hand crimp tool,
from table below (or equivalent). The connector is mounted to the tray back
plate with 4-40 screws (475-440-1038), from the inside of the tray and the
mounting block, 431-891-0100. Ensure that proper strain relief and chafing
precautions are made during wiring and installation, using the cable clamp
(625-001-0002).
Two grounding lugs are provided, which may be attached to the rear mounting
plate with 2 4-40 x ¼” screws with captive lock washers. These provide a
convenient location to connect the shield ground terminations.
Manufacturer Crimping Tool Positioner Extraction Tool
AMP
601966-1 601966-6 91067-1
Daniels
AFM8 K42 M24308-1
ITT-Cannon
995-0001-584 995-0001-739 91067-1
Table 5-1 Connector Pin crimping tools
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5.3 Cable Harness Wiring
Refer to Appendix C for assembling the wiring harness as required for the
installation. All wires must be MIL-SPEC in accordance with current
regulations. Two- and three-conductor with shield wire must be used where
indicated, and be MIL-C-27500 or equivalent specification. Proper stripping,
shielding and soldering technique must be used at all times. It is imperative
that correct wire be used.
Refer to FAA Advisory Circular 43.13-2B for more information. Failure to use
correct techniques may result in improper operation, electrical noise or unit
failure. Damage caused by improper installation will void the Trig warranty.
5.3.1 Noise
Due to the variety and the high power of radio equipment often found in
today's general aviation aircraft, there is a potential for both radiated and
conducted noise interference.
The TMA44 power supply is specifically designed to reduce conducted
electrical noise on the aircraft power bus by at least 50dB. Although this is a
large amount of attenuation, it may not eliminate all noise, particularly if the
amplitude of noise is very high. There must be at least 13.8 VDC present at the
bottom connector, pin 43, of the TMA44 for the power supply to work in its
designed regulation. Otherwise, it cannot adequately attenuate power line
noise. Shielding can reduce or prevent radiated noise such as beacons, electric
gyros, or switching power supplies, but installation combinations can occur
where interference is possible. The TMA44 is designed in a RFI hardened
chassis and has internal Electromagnetic Interference (EMI) filters on all
inputs and outputs.
Ground loop noise occurs when there are two or more ground paths for the
same signal, such as the airframe and a ground return wire. Large cyclic loads
such as strobes or inverters can inject noise signals onto the airframe that are
detected by the audio system. Follow the wiring diagram very carefully to help
ensure a minimum of ground loop potential. Use only MIL-SPEC shielded
wires (MIL-C-275000, or better). Under no circumstances combine a
microphone and headphone wiring into the same shielded bundle. Always use
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a 2 or 3 conductor shielded wire as shown on the installation wiring diagram.
The shields can be daisy-chained together, and then connected to the ground
lugs mounted on the back plate shown in Appendix B.
Radiated signals can be a factor when low-level microphone signals are
"bundled" with current carrying power wires. Keep these cables physically
separated. It is very important that you use insulated washers to isolate the
ground return path from the airframe to all headphone and microphone jacks.
Note: Adding a high-performance audio control system, particularly
in conjunction with active noise cancelling headsets, cannot improve
on older avionics that were designed for cabin-speaker use. Trig
makes no claim that the audio panel will provide a noise-free audio
quality under all installation conditions, particularly with older
avionics.
5.3.2 Entertainment Input (J1 pin 9 & 25)
Two entertainment devices (MP3 player, Portable Satellite Radio, CD player,
etc.) can be connected to the unit. Install two 1/8-inch jacks in a convenient
location so that the pilot can plug in the entertainment devices into the system.
NOTE: Use the low level output of any entertainment device to
connect to the audio panel. Maximum signal level is 2 VAC p-p. DO
NOT use a speaker-level output, this will cause internal damage in
the audio panel.
For a stereo input, we do not recommend tying the left and right channels (tip
and ring) directly together unless approved by the music source manufacturer.
A small series resistor in each channel is usually required. The audio signal at
the entertainment input must be a minimum of 500 mV P-P for optimum music
performance.
5.3.2.1 Soft Mute
The TMA44-system incorporates a "Soft Mute" system. This will mute the
entertainment devices during ICS or radio traffic. While in the ALL or ISO
modes, entertainment 1 is heard by everyone (except by the pilot in ISO
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mode). While in the CREW mode, pilot and co-pilot will hear entertainment 1
while the passengers will hear entertainment 2.
The “Mute” button can be used to inhibit the soft mute function, keeping
music at the same level. In CREW mode, passengers will hear Music 2, and
this will be controlled by the “Mute” button located on the front panel.
Entertainment inputs 1 and 2 can be paralleled so a single entertainment source
can serve both the passengers and the crew in "crew" mode. It is suggested
however, that a switch (DPDT) is installed between the single entertainment
device and entertainment input 1. This will allow the pilot and co-pilot to
decide if they hear entertainment while in the Crew mode.
Local oscillators and internal signals from some entertainment equipment can
cause undesired interference with other aircraft systems. Before take-off,
operate the entertainment devices to determine if there is any adverse effect
within the aircraft systems. If any unusual operation is noted in flight,
immediately switch off the entertainment devices.
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5.3.3 TMA44 Pin assignments
Pin Function Pin Function
1 Co-pilot Mic Audio 2 Pilot Mic Audio Hi
3 Passenger Mic Hi 4 Com 1 Mic Audio
5 Com 1 Mic Key 6 Com 1 Audio In
7 Unswitched 1 Hi 8 Nav 1 Input
9 Music 1 Hi 10 Pilot Headphone
11 Swap 12 Blue Lamp Out
13 Amber Lamp Out 14 Speaker Ground
15 Marker Antenna 16 Co-pilot Mic Lo
17 Pilot Mic Low 18 Passenger 1 Mic Lo
19 Passenger Mic Lo 20 Com 1 Lo
21 Com 2 Mic Key 22 Unswitched 2 Hi
23 Nav 2 Audio Hi 24 Audio Low
25 Music 2 Hi 26 Co-pilot Phones Hi
27 MM Sense 28 Marker Low
29 Airframe Ground 30 Marker Antenna Ground
31 Co-pilot Mic PTT 32 Pilot Mic PTT
33 Passenger Mic Hi 34 Com 2 Mic Audio
35 Com 2 Audio Lo 36 Com 2 Audio
37 ADF Audio Input 38 Aux Audio Hi
39 DME Audio Hi 40 Passenger Phones Hi
41 Dimmer Input 42 White Lamp Out
43 Aircraft Power 44 Speaker Hi
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5.3.4 External Push-to-Talk (J1 pin 32 pilot, J1 pin 31 copilot)
An important part of the installation is the PTT (Push-To-Talk) switches that
allow the use of your aircraft communications radio for transmissions. There
are three typical configurations that can be used. Select the case that best fits
the installation. Only the person who presses their PTT switch will be heard
over the radio. If the pilot and co-pilot both use the PTT, the co-pilot position
has access to the radio. The pilot position will have PTT control regardless of
the co-pilot when the TMA44 is in the F
AIL-SAFE mode.
CASE 1: PTT is built into both pilot and co-pilot yokes.
CASE 2: PTT is in pilot yoke only. This configuration requires a modified
external PTT switch plugged into the co-pilot's microphone jack. (See
Appendix A). When the co-pilot's PTT is pressed, the intercom switches the
mic audio from pilot to co-pilot mic.
CASE 3: No built in PTT. This requires two built in PTTs to be installed, or
modified external PTT switches to be used. Modify external PTT as required
(See Appendix A).
5.3.5 Transmit Interlock
Some communications transceivers use a transmit interlock system which
changes the behaviour of one radio when the other one is transmitting. In
order to use the Split Mode feature, this function will need to be correctly
configured.
If you are using Trig radios, the transmit interlock pin on each radio should be
connected to the PTT of the other radio. For other brands, consult the
manufacturer installation manual.
5.3.6 Power (J1 pin 43)
The TMA44-Series are compatible with both 14 and 28 volt DC systems. A
two (2) amp circuit breaker is required. Power and ground wires must be a
twisted 22 AWG pair.
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Included with this product is a power dropping resistor to be connected in
series with the power input, bottom connector, pin 43. This dropping resistor
is supplied for 28 volt systems so that unnecessary heat dissipation inside the
TMA44 can be avoided.
NOTE: To reduce the amount of heat dissipated in the audio selector
panel, when used in a 28 volt aircraft, a 15
, 15 watt dropping
resistor (p/n 701-015-1501) must be installed in series with the power
input. This resistor should be mounted to aircraft structure to
dissipate heat.
5.3.7 "Swap" Mode (J1 pin 11)
When a normally-open, momentary, push-button switch is connected between
pin 29 on the connector and aircraft ground, the user can switch between Com
1 and 2 by depressing this switch without having to change the mic selector.
This yoke mounted switch eliminates the need of removing your hands from
the yoke to change transceivers.
5.3.8 Backlighting (J1 pin 41)
The brightness of the green audio selection indicators is automatically
controlled by a photocell located in the centre of the unit. The brightness of
the buttons is set by the dimmer control input on pin 41. The unit has an
internal jumper to select between 14 volt and 28 volt electrical systems; when
shipped from the factory it is set to 14 volts. To change to 28 volts, follow the
instructions in section 5.3.9.
If the dimmer control is not connected, a constant low level illumination of the
buttons will be provided for night-time viewing.
5.3.9 Backlight Voltage Adjustment
As shipped from the factory, the TMA44 is configured for 14V dimmer
systems. For 28V dimmer systems remove jumper J9.
NOTE: Take precautions to prevent ESD damage prior to servicing unit
1. Remove the 4 Phillips head screws from the TMA44.
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Figure 5-1 Screw Locations
2. Remove the jumper located in the back corner away from the sub-D
connector from both pins of J9. See Figure 5-2.
3. Place the lid back on the unit, aligning holes.
4. Install and tighten the 4 screws into the lid.
4 screws
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Figure 5-2 Backlight selection jumper location
5.3.10 Middle Marker Sense (J1 pin 27 & 28)
The MM Sense output Pin 27, is connected to certain specific autopilots, and
goes high only when a middle marker signal is received, not in test.
5.3.11 Unswitched Inputs (J1 pin 7, 22 & 24)
The TMA44 has two unswitched inputs. Pin 7 and pin 22 are
unswitched/unmuted inputs that are heard by the crew and over the cockpit
speaker at all times.
5.3.12 Intercom
All mic and headphone (monaural) jacks must have insulating washers, the
cable must be Teflon coated, twisted-shielded wire, and the shield must only
28V backlighting
§5.3.9
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be connected to the ground return wire only at the intercom connector.
5.4 Adjustments
The TMA44 is factory adjusted to accommodate the typical requirements for
most aircraft configurations. There are four adjustments however that will
allow the installer to tailor the specific functions.
Adjustment Clockwise Results In
Cabin Speaker Level Increase Speaker Volume
Marker Beacon Level Decrease Marker Volume
MKR High Sense Increase sensitivity
MKR Low Sense Increase Sensitivity
To make the necessary adjustments, use a small jeweller’s slotted
screwdriver.
Figure 5-3 Adjustments
Speaker
Volume
VR2
MKR Volume
VR912
MKR HI
Sense
VR917
MKR LO
Sense
VR919
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5.5 Marker Antenna Installation
Refer to aircraft and antenna manufacturer's installation instructions, as well as
AC43.13-2B (or later revision), Chapter 3, for information on proper antenna
installation techniques. The marker beacon antenna must be mounted on the
bottom of the aircraft.
5.6 Communications Antenna Installation Notes
For best results while in Split Mode, it is suggested that the one VHF
communications antenna be located on top of the aircraft while the other
communications antenna be on the bottom. Any antenna relocation must be
accomplished in accordance with AC 43.13-2B, aircraft manufacturers’
recommendations and FAA-approved technical data.
Warning: It is probable that radio interference will occur in the split
mode when the frequencies of the two aircraft radios are adjacent,
and/or the antennas are physically close together. Trig makes no
expressed or implied warranties regarding the suitability of the
TMA44 in Split Mode.
5.7 Unit Installation
To install the TMA44, gently slide the unit into the mounting rack until the
hold-down screw is engaged. While applying gentle pressure to the face of the
unit, tighten the 3/32" hex-head screw next to the co-pilot control shaft until
the unit is secure. DO NOT OVER TIGHTEN.
Warning: Do not over-tighten the lock down screw while installing
the unit in tray. Internal damage will resu lt.
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6. Post Installation Checkout
6.1 Required Test Equipment
In order to return an aircraft to service after installation of the TMA4, the
installer must have access to a Marker Beacon signal generator such as one of
the following:
IFR NAV401L, NAV402AP, IFR4000, TIC T-30D, T-36C
Equivalent test equipment is acceptable as long as the testing requirements can
be met.
6.2 Power Test
After wiring is complete, verify power is ONLY on pin 43 of the connector,
and airframe ground on connector pin 29. Failure to do so may cause serious
internal damage and void Trig's warranty.
1. Apply power to the aircraft and avionics.
2. Plug headsets into the pilot, co-pilot, and occupied passenger positions.
3. Verify fail-safe operation by receiving and transmitting on COM 1 from
the pilot position, with the audio panel power off.
4. Switch on the unit by pressing the volume (VOL) knob.
5. Check intercom operation.
6. Push the XMT1 select button.
7. Verify that both the LEDs (Light Emitting Diode) near the COM1 and
XMT1 buttons light. Verify that transmit button LED near the mic
selector is not blinking. If the LED is blinking, stop testing and
troubleshoot the microphone PTT installation.
8. Verify proper transmit and receive operation from the co-pilot position,
noting that the co-pilot PTT switch allows proper transmission on the
selected transceiver. Verify that the LED near the XMT1 button blinks
when transmitting.
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9. Verify that pushing the COM2 button causes the LED near the button to
illuminate, and the COM2 receiver to be heard. Verify operation on
COM1 from the pilot position.
10. Repeat for COM2
11. Press and hold the XMT1 button. While holding the XMT1 button, press
the XMT2 button. This places the unit in “Split Mode”; verify that the
pilot can transmit and receive on COM1, while the co-pilot transmits and
receives on COM2.
12. Verify proper operation of all receiver sources by selecting them using the
appropriate button. The button illuminates to show which source is in use.
13. Push the speaker button. Verify that all selected audio is heard in the
cockpit speaker. Verify that the audio mutes when the mic is keyed.
14. Verify that the appropriate LED in the lower button row blinks when
either push to talk is keyed.
15. Verify proper Intercom system operation in the A
LL, ISO and CREW
modes (see Section 8.12).
16. Verify that the audio selector panel system does not adversely affect any
other aircraft system by systematically switching the unit on and off,
while monitoring the other avionics and electrical equipment on the
aircraft.
6.3 Marker Checkout
1. Connect a ramp generator at the antenna end of the marker coax. With the
unit under test in HI sensitivity, verify that a 160 V, modulated 95%
with 1300 Hz, signal will illuminate the amber (M) marker light, and that
marker audio is present in the headphones when the Marker Audio
(MKR) push-button has been depressed. Select the button with the
speaker symbol to verify marker audio availability on the cabin speaker.
Verify that the white (I) and blue (O) lights will illuminate within 3dB
of the amber lamp, with 3000 HZ and 400 Hz applied, respectively.
2. Repeat with the unit in LOW sensitivity, with 430 V applied.
3. Connect the marker antenna and verify proper operation.
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7. Final Inspection
Verify that the wiring is bundled away from all controls and no part of the
installation interferes with aircraft control operation. Move all controls
through their full range while examining the installation to see that no
mechanical interference exists. Verify that the cables are secured to the aircraft
structure in accordance with good practices, with adequate strain relief. Ensure
that there are no kinks or sharp bends in the cables and coaxial cables. Verify
that the cables are not exposed to any sharp edges or rough surfaces, and that
all contact points are protected from abrasion. Complete logbook entry, FAA
Form 337, weight and balance computation and other documentation as
required.
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8. Normal Operation
8.1 Front Panel
8.2 Power On and Fail-Safe Operation
The audio panel is turned on and off by pressing the volume control knob
(smaller, inner knob on left side of unit).
When the system is turned off or if power is removed the audio panel will be
placed in the fail-safe mode. In the off or fail-safe mode, the pilot is
connected directly to Com 1 and to unswitched input 1, allowing transmit,
receive and alert capability regardless of audio panel condition.
8.3 Transmitter Selection
To select a radio for transmission, press either the XMT1 or the XMT2 button;
the green indicator lamp above the button will light up, indicating which radio
you will transmit on. The corresponding COM1 or COM2 indicator will also
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light up; you always hear the audio from the transceiver that is selected for
transmit.
Both pilots can transmit on the selected radio, but only the person who presses
their Push-To-Talk switch will be heard over the aircraft radio.
8.4 Receiver Selection
To listen to both radios press the COM1 or COM2 button as required to enable
the second radio. Both radios will remain selected until one is manually
deselected.
8.5 Navigation Audio Selection
The MKR, NAV1, NAV2, DME, ADF and AUX buttons select the switched
navigation receivers. Press once to turn on the corresponding source, press
again to turn it off.
A green lamp above the button will light indicating which audio source is
selected.
8.6 Cockpit Speaker
This button will place all selected audio on the cockpit speaker when active.
Note: In Split mode (see below), only unswitched inputs will play
through the speaker.
To help reduce power consumption and internal heat build-up in the avionics
stack, switch off the speaker when not in use.
8.7 Swap Mode
The optional Swap button, usually mounted on the control yoke, switches
between the Com transmitters without having to reach for the audio panel.
Pressing the Swap button has exactly the same effect as switching between
XMT1 and XMT2 on the audio panel.
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8.8 Split Mode
Pressing both XMT1 and XMT2 buttons at the same time puts the TMA44
into Split mode; all four COM and XMT indicators will light up. This
connects the pilot to Com 1 and the co-pilot to Com 2, and they can use their
respective radios independently. The passengers will not hear the radios or
crew intercom in Split mode.
Press either XMT button to exit Split mode.
It is not possible to place the pilot on Com 2 and the co-pilot on Com 1.
In Split mode only the pilot will hear the selected navigation audio.
An example of this feature is when the pilot may want to talk to Air Traffic
Control, while the co-pilot may be speaking to ground handling agents.
Note: Due to the nature of VHF communications signals, and the
size constraints in general aviation aircraft, it is probable that
there will be some transmission bleedover in Split Mode,
particularly on adjacent frequencies. Split Mode may not be
suitable in all aircraft conditions.
8.9 Intercom Volume
Turning the volume control knob (the smaller, inner knob on the left side of
the audio panel) adjusts the intercom volume in all headphones for pilot, copilot, and passengers. It has no effect on selected radio audio or music levels.
Many general aviation headsets have a built-in volume control, so volume can
also be adjusted locally.
8.10 Intercom Squelch
The TMA44 provides a single VOX squelch control for the pilot, co-pilot and
the passengers, although each microphone input has its own squelch circuit.
Only the microphones spoken into will be open, thus reducing the amount of
background noise.
With the engine running, set the VOX squelch by slowly rotating the SQ
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control knob (the larger, outer knob on left side of unit) clockwise until you no
longer hear the engine noise in the headphones. When the microphone is
positioned properly near the lips, normal speech levels should open the
channel.
When you have stopped talking, there is a delay of about ½ second before the
channel closes. This helps prevent choppy communications.
8.11 Intercom Modes
The Intercom (I/C) button is a 3-function mode selector that allows the pilot to
tailor the intercom function to best meet the situation; it cycles through the
following modes, from top to bottom:
PILOT: The pilot is isolated from the intercom and is connected only
to the aircraft radios. Co-pilot and passengers will hear the intercom
and Music 1, but not the aircraft radio receptions or pilot
transmissions.
ALL: All parties will hear the aircraft radios, intercom, and Music 1.
CREW: Pilot and co-pilot are connected on one intercom channel and
have exclusive access to the aircraft radios. They may also listen to
Music 1. Passengers can continue to communicate amongst
themselves without interrupting the crew and may listen to Music 2.
When in Split mode the pilot and co-pilot do not have any intercom function,
the passengers will maintain communications.
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8.12 Intercom Mode Table
Mode Pilot
Hears
Co-pilot
Hears
Passengers
Hear
Comments
Pilot
Radios
Sidetone
Passengers
Music 1
Co-pilot
Passengers
Music 1
This mode allows the pilot
to communicate with air
traffic control without the
co-pilot or passengers
hearing the conversation.
Co-pilot and passengers
can continue to talk and
listen to music.
All
Radios
Sidetone
Co-pilot
Passengers
Music 1
Radios
Sidetone
Pilot
Passengers
Music 1
Radios
Sidetone
Pilot
Co-pilot
Passengers
Music 1
This mode allows all on
board to hear radio
reception as well as
communicate on the
intercom.
Crew
Radios
Sidetone
Co-pilot
Music 1
Radios
Sidetone
Pilot
Music 1
Passengers
Music 2
A second music source is
automatically enabled for
the passengers.
8.13 Music Inputs
The audio selector panel has provisions for up to two separate music input
devices. Which device is heard is determined by the intercom mode selected.
It is also possible to use a single input device for both music inputs. A switch
may be installed between the single input device and music input 1; this will
allow the pilot and co-pilot to decide if they hear music devices while in Crew
mode.
8.14 Music Muting
The Mute button controls the muting circuits of both music inputs. During
voice communication, the music volume automatically decreases when mute is
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active; the music volume increases gradually back to the original level after
communications are complete.
8.15 Marker Beacon Receiver
The marker beacon receiver uses visual and audio indicators to alert you when
the aircraft passes over a 75 MHz beacon transmitter.
The marker beacon audio can be enabled and disabled by pressing the MKR
button. A green lamp to the right of the button will light when the audio is
enabled.
The blue outer marker lamp has an associated 400 hertz 'dash' tone.
The lamp and tone are keyed at a rate of two per second when the
aircraft is in the range of the outer marker.
The amber middle marker lamp is coupled with a 1300 hertz tone,
keyed alternately with short 'dot' and long 'dash' bursts at 95
combinations per minute.
The white inner marker lamp has a 3000 hertz 'dot' tone. The lamp
and tone are keyed at a rate of six times per second.
The sensitivity (SENS) button can be used to change the marker beacon
receiver sensitivity to high or low. Use HI sensitivity only when navigating
using fan markers on airways. For normal ILS marker beacons the sensitivity
should always be set to LO.
Holding the SENS button for one second illuminates all three lamps
simultaneously to assure the lamps (internal and external) are in working
order. It will also cause the marker audio to mute for that beacon; the next
beacon received will reactivate the audio. Releasing the SENS button restores
the last sensitivity.
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9. Continued Airworthiness
Other than for periodic functional checks required by the regulations, the
TMA44 audio panel has been designed and manufactured to allow “on
condition maintenance”. This means that there are no periodic service
requirements necessary to maintain continued airworthiness, and no
maintenance is required until the equipment does not properly perform its
intended function. When service is required, a complete performance test
should be accomplished following any repair action. Repairs should only be
carried out in accordance with Trig Avionics Limited service procedures.
9.1 Cleaning the Front Panel
The plastic body and switches should be cleaned with a soft cotton cloth
moistened with clean water.
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10. Limited Warranty
Trig Avionics Limited warrants our products to be free from defects in
materials and workmanship for a period of two (2) years from the date of
installation by an authorised dealer.
This warranty covers repair and/or replacement at our option, of any parts
found to be defective, provided such defects in our opinion are due to faulty
material or workmanship and are not caused by tampering, abuse, or normal
wear.
All warranties are F.O.B.
Trig Avionics Limited
Heriot Watt Research Park
Riccarton, Edinburgh, EH14 4AP
Trig Avionics will not accept or pay for any charges for warranty work
performed outside our factory without prior written consent.
This warranty applies only to products in normal use. It does not apply to units
or circuit boards defective due to improper installation, physical damage,
tampering, lightning or other electrical discharge, units with altered serial
numbers, or units repaired by unauthorised persons or in violation of Trig
Avionics Limited service procedures.
Trig Avionics Limited assumes no responsibility for any consequential losses
of any nature with respect to any products or services sold, rendered, or
delivered.
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11. Environmental Qualification Form
Nomenclature: TMA44 Audio Panel
Part Number: PS Engineering Part Number: 6000, Trig Part Number 01801-
00-01
TSO C50c, C35b Class A
ETSO: C50c, 2C35d EASA.IM.21O.10028565
Manufacturer: PS Engineering Incorporated, 9800 Martel Road, Lenoir City,
TN
Conditions DO-160B Description of Conducted Tests
Temperature and Altitude 4.0 Equipment tested to Category A1
Low temperature 4.5.1 -20°C
High temperature 4.5.2 +55°C
Altitude 4.6.1 50,000 feet, Equipment tested to Category D1
Temperature Variation 5.0 Equipment tested to Category C
Humidity 6.0 Equipment tested to Category A
Shock 7.0 Equipment tested to Category B
Vibration 8.0 Equipment tested to Category M, Standard
Explosion 9.0 Equipment identified as Category X – no test
required
Waterproofness 10.0 Equipment identified as Category X – no test
required
Fluids Susceptibility 11.0 Equipment identified as Category X – no test
required
Sand and Dust 12.0 Equipment identified as Category X – no test
required
Fungus 13.0 Equipment identified as Category X – no test
required
Salt Spray 14.0 Equipment identified as Category X – no test
required
Magnetic Effect 15.0 Equipment identified as Category X – no test
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required
Power Input 16.0 Equipment tested to Category B
Voltage Spike 17.0 Equipment tested to Category B
Audio frequency conducted
susceptibility
18.0 Equipment tested to Category B
Induced signal
susceptibility
19.0 Equipment tested to Category B
Radio frequency
susceptibility
20.0 Equipment tested to Category A
Radio frequency emission 21.0 Equipment tested to Category A
Lightning induced transient
susceptibility
22.0 Equipment not tested
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Appendix A External PTT Hook Up
Part of the installation includes the installation of PTT (Push-To-Talk)
switches that allow the use of your aircraft radio for communications
transmissions. There are three configurations that can be used, you must select
the case that best fits your installation.
CASE 1 - The PTT is built into the pilot and co-pilot yokes
Simply install the plugs from the headset into the aircraft headphone jacks.
Then use the yoke mounted PTT to transmit. No other action is required.
CASE 2 - Built in PTT only on the pilot side only
This configuration requires a modified external PTT switch plugged into the
co-pilot's mic jack – see modification details below. When the co-pilot's PTT
is depressed, this activates an internal relay that switches the mic audio to the
aircraft radio from the pilot to the co-pilot.
CASE 3 - No built in PTT switch at all
Two built-in PTT must be installed, or two external, modified PTT switches
will be required for both the pilot and co-pilot – see modification details
below.
Push To Talk Modifications
When received from the manufacturer, an after-market PTT switch opens the
mic audio path to the "ring" connection of the PTT mic plug until the button is
pressed. When the PTT is between the intercom and the headset, the intercom
function will not work unless the PTT switch is depressed. A simple
modification can be performed to allow proper intercom operation. NOTE:
This mod does not alter normal operation.
Below are some examples of typical modifications. Contact Trig Support or
the PTT manufacturer for more details if necessary.
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Procedures for David Clark PTT
1. Unscrew the round black plastic cover from the jack.
2. Connect the joined black wires to the red wire.
3. Replace the round black plastic cover.
Procedures for Telex PT-200
1. Unscrew the round black plastic cover from the jack.
2. Cut the red wire in the middle of the wire.
3. Strip both ends of the insulation.
4. Solder the two ends to the ground lug to the PTT jack.
5. Replace the round black plastic cover.
Procedures for Telex PT-300
1. Unscrew the round black plastic cover from the plug jack.
2. Remove the heat shrink material from the joined black wires.
3. Solder these two wires to the lug that has a white wire already soldered to it.
4. Replace the round black plastic cover
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Appendix B Installation Drawings
Drawings are not to scale
431-891-0100 Retaining Block
44-pin connector
Rack back plate
430-890-0050
475-440-0007 (4 ea)
475-440-1038 ( 2)
Rack
430-890-0040
Ø0.20 in
8 plcs
Ø0.50 in
2 plcs
J1
Viewed from Back
15
30
44
1
16
31
Ground Lug
Ground Lug
475-440-0001 (x2)
Back plate assy
475-009-0001
ground lug (x2)
475-440-0001 (x2)
Screw w/washer
Ground lug detail
Not used
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0.37in
3.87in
5.53in
6.04in
0.36in
0.96in
1.28 in
6.31in
1.28in
Caution: Apply steady pressure to the bezel while screwing the unit into the
tray to ensure even seating of the unit and connectors.
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Appendix C Wiring/Interconnect
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6
20
4
5
Communications
Transceiver #1
COM 1 Audio Hi
COM 1 Low
COM 1 Mic Au dio
COM 1 Mic Key
Communications
Transceiver #2
COM 2 Audio Hi
COM 2 Low
COM 2 Mic Au dio
COM 2 Mic Key
36
35
34
21
Nav 1 Audio Hi
Na v 1 Low
8
VHF Nav 1
Na v 2 Audio Hi
Nav 2 Low
23
VHF Nav 2
ADF Audio Hi
ADF Low
37
ADF Receiver
DME Aud io Hi
DME Low
39
DME Receiv er
AUX Aud i o Hi
AUX Low
38
AUX (MKR)
Unswitched 1 Hi
Unsw Low
7
Unsw Audio 1
Unswitched 2 Hi
Unsw Lo w
22
24
Unsw Audio 2
9
Music 1 Hi
Music Low
25
Mus ic 2 Hi
Music Low
10
Pilot Phones Hi
Pilot Phones Lo
26
40
Copi lot P ho ne s Hi
Cop ilot Phones L o
Passenger Phone s Hi
Passenger Pho nes Lo
Pilot Mic Audio Hi
Pilot Mic PTT
Pilot Mic low
2
32
17
Pilo t Ra dio
PTT
Copilot Mic Audio Hi
Copi lot Mic PTT
Copilot Mic low
1
31
16
Copilo t
Ra dio PTT
3
18
Pass Mic Hi
Pass Mic Low
33
19
Pass Mic Hi
Pass Mic Low
44
14
Spea ker Hi
Speaker low
42
12
13
27
28
External Marker lamp (White)
External Marker lamp (Blue)
External Marker lamp (Amber)
MM Sense
Marker Low
15
30
RG-5 8A /U Coax
Mar ker An tenna
11
Swap
41
43
29
14/2 8V Li gh ts Hi
14 /2 8V Low
15 Ω 15W
(28V Installation only )
11-33V
Airframe Ground
1. All shields should be grounded at audio panel only.
Other ends remain floating.
2. All phone and mic jacks must be floating from ground.
Use insulating washers.
3. All wiring to conform to MIL 22750 or 27500.
4. All Power and Ground wires must be #22 gage wire
5. External speaker loads may be required on some
transceivers. Consult manufacturer's information.
6. 28V installations require 15 ohm, 15W dropping
resistor. Not required for 14v aircraft.
7. Reserved
8. Marker Lamp outputs (42, 12, 13) go to +7 VDC, +/- 4VDC
when active.
9. MM Sense output (pin 27) goes high when middle
marker signal received.
10. Pins 7 and 22 are unswitched, unmuted input. Pin 7
is present in pilot headset in Fail-Safe.
11. Unit is shipped from factory for 14v lights.
Remove internal J9 for a 28v lighting bus.
See section 2.4.7.1
12. All receiver audio los connected to Pin 24
13. Shield grounds can be connected to the solder lug, and lug
connected to the aircraft ground pin.
Note 4, 6, 11
Note 10
Not e 7
Note 12
Note 13
2 A
Pas se nger Ph ones Hi
Passenger Phones Lo
Passenger Headpho ne
Jacks
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