Northern Airborne Technology AA9x User Manual

Installation and Operation Manual

AA9x Series

Single Channel Audio Controller

SM56

ISSUE 4.01

Northern Airborne Technology Ltd.

1925 Kirschner Road

Kelowna, BC, Canada.

V1Y 4N7

Telephone [phone]

Facsimile [phone]

Issued on the authority of Northern Airborne Technology Ltd.

Copyright 2002

AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

IMPORTANT INFORMATION

This manual has been produced to provide information unique to the

AA9x Series Single Channel Audio Controller. Some of this information

has been published previously in the SM01 Service manual

(AA90/AMS40 Series Audio Controllers).

The information presented in this manual is for reference purposes only,

and is intended to provide general information that can be used by the

installer/technician to gain a fundamental understanding of the respective

product. It is not intended to cover all variations of the AA9x Series audio

controllers. Drawing packages for specific AA95, AA96 and AA97 units

can be requested from NAT by contacting the Product Support

Department.

Earlier versions of the AA9x Series (prior to Serial number 6000) may not

be covered by the information in this manual. Please refer to SM01, or

contact the Product Support Department at NAT Ltd.

Installation and Operation Manual Page ii

ENG-FORM: 820-0115.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

Prepared By: Checked By: Approved By:

The status of this installation and operation manual is controlled by issue shown on the title page. The
status of each section is controlled by revision shown in the footer of each page. All revisions affecting
sections of this manual have been incorporated into the latest issue.

ISSUE/REVISION RECORD

Manual Issue

Number

1.00 N/A Initial Issue Oct 23, 2002

4.00 N/A Split Manual Nov 10, 2003

Section

Revision Number

Revision Description Issue Date

4.01 Section 1 Rev: 1.00

Update to current templates. Sept 05, 2008
Section 2 Rev: 1.00
Section 3 Rev: 1.00

Installation and Operation Manual Page iii

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

Table of Contents

Section Title Page

1. Description

1.1 Introduction 1-1

1.2 Product Description 1-1

1.3 Design Features 1-1

1.4 Specifications 1-2

1.4.1 Electrical Specifications 1-2

1.4.2 Physical Specifications 1-3

1.4.3 Environmental Specifications 1-3

1.5 Unit Nomenclature 1-3

2. Installation

2.1 Introduction 2-1

2.2 Unpacking and Inspection 2-1

2.2.1 Warranty 2-1

2.3 Continued Airworthiness 2-1

2.4 Installation Procedures 2-2

2.4.1 Warnings 2-2

2.4.2 Cautions 2-2

2.4.3 Cabling and Wiring 2-2

2.4.4 In-line PTT Cordsets 2-2

2.4.5 Post Installation Checks 2-4

2.5 Adjustments and Connections 2-5

2.5.1 Left Side Panel Adjustments 2-5

2.5.2 Right Side Panel Adjustments 2-6

2.6 Accessories Required But Not Supplied 2-6

2.7 Installation Drawings 2-7

3. Operation

3.1 Introduction 3-1

3.2 General Information 3-1

3.3 Controls and Indicators 3-1

3.3.1 Receive Audio Select Switches 3-2

3.3.2 Transmit Selector Switch 3-3

3.3.3 ICS Functions 3-3

3.4 Optional Features 3-4

3.4.1 ICS ISO and/or PLT ISO Annunciators 3-5

3.4.2 ICS CALL Annunciator 3-5

3.4.3 ICS CALL Switch 3-5

3.4.4 PAT ON/OFF Switch 3-5

3.4.5 ICS TIE/SPLIT Switch 3-5

3.5 Emergency Operation (AA95 and AA97 models only) 3-5

3.6 Audio Alerting Functions (AA95 and AA97 models only) 3-6

3.6.1 Direct Audio 3-6

3.6.2 Internal Alerting 3-6

Installation and Operation Manual Page iv

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

Section 1 Description

1.1 Introduction

Information in this section consists of product description, design features and specifications for the
AA9x Series Single Channel Audio Controller. All derivative product information shall be contained in the
applicable manual supplement, which may be obtained from NAT as required.

Review all notes, warnings and cautions.

1.2 Product Description

The AA9x series provide control for all aircraft audio, allowing selection of transmit and receive audio,
LIVE, KEYED, or VOX intercom, interface for an additional hand held transmit microphone (hand mic),
and pilot isolation/emergency operation.

Transmit and PA functions are controlled with a single rotary switch. Receive audio, ICS operations and
tape audio are controlled with toggle switches. Receive volume, ICS volume and ICS VOX squelch are
individually adjusted with rotary controls. Sidetone (S/T) level is adjustable internally and the AA97 also
has an individual RX level control for each transceiver.

1.3 Design Features

The AA9x series are Dzus rail mounted units with lighted faceplates. Transceiver interfacing is
accomplished through directly switched microphones. To ensure maximum radio compatibility, it has a
ground-referenced keyline that incorporates no diode s or other steering components.

Independent control is provided for each audio channel within the controller, allowing sidetone, ICS audio
and RX audio to be independently set.

Boom mic support is provided for the pilot and co-pilot, with both ICS and XMIT functions via cyclic or
yoke switching. In some models, a third ‘transmit capable’ boom mic is added. Live (Hot Mic) and VOX
ICS are also provided, with a ‘transparent’ function, allowing immediate transmission via this mode
without further control panel switching and immediate return to ICS operation on completion. The ICS
(intercom) function is achieved using dynamic noise reduction and active filtering. This provides the
clearest possible ICS audio under high ambient noise conditions by rejecting airframe and wind noise and
passing only voiceband information.

All audio, except the S/T of the radio in use and certain DIRECT AUDIO input signals, is muted during
transmit for clarity. ICS operation allows transmit during any ICS mode by using the transmit PTT switch.

All switches, relay contacts and external connections are gold plated for maximum reliability. Switches
and relays are sealed. G10-FR flame retardant circuit boards are postcoated for maximum mo isture
resistance and corrosion prevention. Relays are sealed, high vibration rated (50g shock), dry nitrogen
filled units.

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

1.4 Specifications

1.4.1 Electrical Specifications

Input Power

Input Signals

Output Signals

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Nominal 27.5 Vdc Nominal @ 0.50 A Max.
Lighting 27.5 Vdc @ 160 mA
Alert Power 27.5 Vdc Nominal @ 150 mA Max.

Quantity 13 receive channels
7 mic channels
1 ICS tie channel
1 or 2 direct channels

Audio level 2.5 Vrms for receiver inputs

0.25 Vrms for mic inputs

2.5 Vrms for direct audio inputs
Impedance 1 kΩ ±10% for receive inputs

1 kΩ ±10% for mic inputs

1.6 kΩ ±10% for ICS tie input

1.3 kΩ ±10% for Direct Audio1 input
100 Ω ±10% for Direct Audio 2 input

Circuit Type All are single ended inputs
Coupling <-40 dB
Keylines Pilot & copilot transmit PTT

Rear hand mic transmit PTT
Pilot & copilot ICS PTT
3 Alerts - active low

Quantity 6 Headphone outputs
Up to 7 Transmitter mic outputs (incl. PA)
Up to 7 Transmitter keyline outputs (incl. PA)

Headphone 7.7 Vrms or 100 mW (20 dBm) into 600 Ω nominal
Direct Audio 1 10 mW (10 dBm) into 600 Ω nominal
Direct Audio 2 0.1mW (-10 dBm) 0.25 Vrms into 600 Ω nominal
Alert 90 mVrms ±10% into 600 Ω nominal

Circuitry Type Headphones are balanced
Mic and ICS Tie are single ended

Distortion <10% THD @ nominal power output
Audio Noise Level >50 dB down from rated output (no signal)
Coupling <-40dB
Output Regulation <10% distortion @ 3 dB max. of rated output power at 400% and

75% of rated load

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

Bi-directional Signals

Miscellaneous

Quantity 1 ICS tie channel
Audio level 0.34 Vrms for NAT ICS tie
Impedance 1.8 kΩ ± 10% for NAT ICS tie input
Circuitry Type Single ended

Annunciators Green LED will light for transmit operation

1.4.2 Physical Specifications

AA95 AA96 AA97
Height
Depth
Width
Weight
Mounting
Faceplate
Material/Finish
Connectors

1.90" (48.3 mm) 1.90" (48.3 mm) 3.00" (76.2 mm)

6.82" (173.2 mm) 6.82" (173.2 mm) 6.82" (173.1 mm)

5.00"(127.0 mm) 5.00" (127.0 mm) 5.75" (146.1 mm)

2.1 lbs. (955 g) 2.1 lbs. (955 g) 2.5 lbs (1.14 kg)
Dzus rail

Engraved acrylic edge lit panel

Chassis & cover are 5052-H32 brushed aluminum with chromate conversion finish

Male 50 pin & 37 pin D-submin connectors with slide locks

1.4.3 Environmental Specifications

Temperature -20 to +55°C (ambient)

-55 to +85°C (survival)
Altitude 25,000 feet max.
Humidity 95% Non-condensing
Vibration/Shock Conforms to DO-160C Cat. ‘N’

1.5 Unit Nomenclature

AA95-512 VHF 1, VHF 2, RT1, RT2, RT3, RT4 XCVRs

NAV, AUX switched Nav-Aids
2 unswitched alerts provided
RX and ICS level controls
ICS Call LED from rear controller
ICS Tie/Split switch

AA95-728 Full pilot and co-pilot support
2 Comm, 2 FM and AUX XCVR positions
5 Nav-Aids plus music input
KEYED, LIVE, VOX ICS with front panel control
3-level alerting
ICS CALL annunciator
Illuminated TX selector knob
1 Direct Audio input

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

AA95-729 Full support for Doctor, Nurse and Attendant

ICS only for 2 positions plus patient
2 Comm, 2 FM and AUX XCVR positions
ADF, Doppler and music inputs.
1 Direct input
ICS CALL switch, PLT ISO annunciator
5 Nav-Aids plus music input
KEYED, LIVE, VOX ICS with front panel control
Illuminated TX selector knob

AA96-001 TX 1, TX 2, TX 3, TX 4, TX 5 and PA XCVRs
2 NAV and 2 ADF unswitched RX inputs
No internal alerting
VOX/LIVE ICS with squelch adjustment
Pilot/Co-pilot boom mic support with pilot priority
4 PAX ICS only support
Front panel master RX and ICS level controls

AA96-400 Full support for Jumpmaster and observer
VHF 1, VHF 2, FM1, FM2, INT and PA XCVRs
2 NAV and 2 ADF unswitched RX inputs
KEYED/LIVE ICS operation
4 PAX ICS only supported
Front panel RX and ICS level controls
PIL ISO annunciator and ICS CALL pushbutton

AA97-402 VHF 1, VHF 2, TAC1, TAC2, TAC3, TAC4 XCVRs and PA
Each XCVR has independent RX level adjustment
NAV1, NAV2, ADF1 and DME switched Nav-Aids
1 Direct Audio input
3 Audio alerts installed
TX/PA and locking ISO/EMR switches
No hand mic connection
Pilot/co-pilot boom mic support with pilot priority
4 PAX ICS only supported
Front panel RX and ICS level controls

Section 1 ends

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

Section 2 Installation

2.1 Introduction

Information in this section consists of unpacking and inspection procedures, installation procedure s, po st­installation checks and installation drawings for the AA9x Series Single Channel Audio Controller.

Note: The AA95, AA96 and AA97 series single channel audio controllers are cu stomized units and may

have unique operational features that are different to the options described, or are not covered in
this manual. Any questions should be directed to the NAT Product Support Department.

Review all notes, warnings and cautions.

2.2 Unpacking and Inspection

Unpack the equipment carefully and locate the warranty card. Inspect the unit visually for damage due to
shipping and report all such claims immediately to the carrier involved. Check that all items listed below
are present before proceeding and report any shortage immediately to your supplier:

- Warranty Card

- Operators Manual

- Certificate of Conformity or Release Certification

2.2.1 Warranty

All Northern Airborne Technology Ltd. products are warranted for 2 years from date of installation by an
authorized NAT dealer, to be free of defects in workmanship or performance. This warranty covers all
materials and labour, but is exclusive of any transport to deliver the defective unit to and from NAT or its
designated warranty repair center, or any labour to remove or re-install the defective unit in the aircraft.
Contact NAT for any questions regarding this warranty, its applicability to your units and/or for return
authorization. NAT is the final arbitrator concerning warranty administration. Units which have been
physically damaged, burned, immersed in water or otherwise abused beyond the scope of normal use will
not be considered for warranty. WARRANTY IS VOID UNLESS THE PRODUCT IS INSTALLED BY AN
AUTHORIZED NAT DEALER. Product for which a warranty card is not returned shall be warranted from
date of manufacture.

2.3 Continued Airworthiness

Maintenance of the AA9x Series Single Channel Audio Controller is ‘on condition’ only. Periodic
maintenance of this product is not required.

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

2.4 Installation Procedures

2.4.1 Warnings

High volume settings can cause hearing damage.

Set the headset volume control to the minimum volume setting prior to

conducting tests, and slowly increase the headset volume to a

comfortable listening level.

2.4.2 Cautions

Failure to follow the installation and wiring instructions provided in this manual

for power and ground connections, including the rating of the circuit breaker,

may lead to damage in the power input circuitry of the unit.

WARNING:

CAUTION:

2.4.3 Cabling and Wiring

All wire shall be selected in accordance with the original aircraft manufacturer's Maintenance Instructions
or AC43.13-1B Change 1, Paragraphs 11-76 through 11-78. Unshielded wire types shall qualify to
MIL-W-22759 as specified in AC43.13-1B Change 1, Paragraphs 11-85, 11-86, and listed in Table 11-11.
For shielded wire applications, use Tefzel MIL-C-27500 shielded wire with solde r sleeve s (fo r shield
terminations) to make the most compact and easily terminated interconnect. Follow the connector map in
Section 2.7 as required.

Allow 3" from the end of the shielded wiring to the shield termination to allow the connector hood to be
easily installed. Reference the interconnect drawing in Section 2.7 for shield termination details. Note that
the hood is a "clamshell" hood, and is installed after the wiring is complete.

Maintain wire segregation and route wiring in accordance with the original aircraft manufacturers
Maintenance Instructions.

Unless otherwise noted, all wiring shall be a minimum of 22 AWG, except power and ground lines, which
shall be a minimum of 20 AWG. Reference the Interconnect drawing for additional specifications. Check
that the ground connection is clean and well secured, and that it shares no path with any electrically noisy
aircraft accessories such as blowers, turn and bank instruments or similar loads.

2.4.4 In-line PTT Cordsets

In-line, push-to-talk (PTT) cordsets (also known as drop cords) can be used to create/provide PTT
capability for the user headsets that do not have yoke or cyclic mounted PTT switches. For headsets
connected to the PILOT or COPILOT inputs/outputs of the AA9x series, ICS and TX keylines are needed
to properly activate the associated PTT circuitry inside the AA9x series. For headsets connected to the
PASSENGER inputs/outputs of the AA9x series, a method of controlling the microphone on the headset
is needed because of the 'hot mic' circuitry. This is best accomplished with a 'mic interrupt' switch in the
PTT cordset.

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

There are numerous manufacturers of in-line PTT cordsets, offering many 'electrical' variations to
accomplish different functions. To meet the operational requirements for headset stations supported by
the AA9x series, NAT recommend the dual switch type: a 3-position (momentary/center-off/locking) slider
switch for the ICS functions and a momentary push-button switch for the Transmit functions. Both
switches provide a ‘mic interrupt’ function. The 3-position ICS switch will allow the user to change the
switch settings to match the operational intercom mode that has been selected at the AA9x series
(e.g., LIVE, KEYED or VOX). The cable should have 6 conductors with the MIC and PHONE pairs
shielded (MIC wires must be shielded as a minimum). To ensure proper shieldin g, the shield(s) should be
terminated to the MIC LO connection at the airframe connector of the PTT cordset. See Figure 1 below
for details.

Figure 1: PTT Cord for Use with NAT Audio Controllers (XMIT and ICS)

To avoid complications in the aircraft, it is recommended that the same type of PTT cordsets be used for
all headset locations in the aircraft. It is not good practice to create a situation where a specific cordset is
needed for the copilot, which might cause operational errors if moved to a passenger location.

Although in-line PTT cordsets can be used to conveniently address a number of requi rements for
microphone and PTT control, they can also be a source of trouble if incorrectly configured, or improperly
shielded.

Many in-line PTT cordsets use the PHONE LO connection as the ground reference for the ICS and TX
PTT keylines. The PHONE LO connection in the AA9x series is floating, which will lead to incorrect keying
of the intercom and radio systems if this type of cordset is used.

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

In-line PTT cordsets can be a source for crosstalk if the MIC wire pair in the cordset is not shielded. The
source of the crosstalk is the high level Phones audio being coupled on to the MIC HI/LO pair in the
in-line PTT cordset, because of the lack of shielding for this wire pair. Once the mic line is contaminated,
the undesired audio can be sent into the audio system as ‘mic audio’, then processed and distributed to
all other audio controllers via the ICS Tie Line.

2.4.5 Post Installation Checks

2.4.5.1 Voltage/Resistance Checks
Do not attach the AA9x Series until the following conditions are met.

Check the following:

a) Check P101, pins <16> and <17> for +28 Vdc relative to ground.
b) Check P101 pin <34> for continuity to ground (less than 0.5Ω).
c) Check P102 pin <19> for lights buss voltage.
d) Check all Mic, phone, music and key lines for shorts to ground or adjacent pins.

2.4.5.2 Power On Checks

Power up the aircraft’s systems and confirm normal operation of all functions of the AA9x Series. Refer to
Section 3 (Operation) for specific operational details.

a) Begin with only the Pilot's headset installed, no hand mic. Confirm correct radio operation,

both receive and transmit. Check yoke (or cyclic) switch action. Check radio audio inputs a nd
selection of same.

b) If there is a music source in the system turn it on and verify that music is muted in the CREW

mode and removed in the PLT ISO mode. Check for proper mute operation. Do not proceed
until the radios are functioning corre ctly. The S/ T (sidetone ) trimpot accessi ble through t he left
side of the controller and t he tra nsceiver internal trimpot may have t o be a djusted f or corre ct
balance for the pilot. Adjustme nt of the i ndividual radio RX l evels sho uld be set fi rst with t he AA9x
series in Pilot ISO mode; then adjust the AA9x series front panel RX master volume control level
in NORMAL mode.

c) Unusual buzzes, hums or other background audio are symptomatic of multiple grounds, or

noisy external systems such as blowers or pumps sharing wiring with the audio system.
Failure to key or correctly modulate a transmitter is often the result of forgetting to connect all

required grounds to the radio or external audio system.
d) Check the ICS Modes (ALL, CREW, PLT ISO), and the manual Fail-safe operation.
e) Plug in the Co-pilot's headset. Check for correct ICS and SPLIT transmit operation. Check

that the Co-pilot loses transmit capability during PLT ISO. Check yoke switch functions.
f) Plug in the hand mic, if installed, and test for correct operation in all modes. (Hand mic

activation does not illuminate the TX light.) Note that wiring faults for this accessory may

cause peculiar loss of ICS or TX functions because it has over-riding priority in the system.
g) Plug in any remaining headsets, and check for correct ICS operation. Note that an incorrect

cordset (drop cord) or improper jack wiring may cause a wide range of problems from loss of

audio to a tone heard in the headset. For further information, see section 2.4.4 above.
i) To verify proper operation, all functions and levels shall be checked in-flight.
j) Check preset adjustments are completed before aircraft departure.

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

Upon satisfactory completion of all performance checks, make all required log book entries, electrical
load, weight and balance amendments and other documentation as required by your local regulatory
agency before releasing the aircraft for service.

2.5 Adjustments and Connections

The unit is shipped from the factory with all internal adjustments set to the normal test levels. Once
installed in the aircraft, it may be desirable to change some of these settings to best suit the local
operating environment. The internal adjustments are located on the sides of the unit and are shown in
Figure 2 and Figure 3.

2.5.1 Left Side Panel Adjustments

The trimpots on the left side panel shown in Figure 2 are used to adjust the levels of audio in the user’s
headphones. Rotating the trimpots clockwise (cw) increases the level and counter clockwise (ccw)
reduces it.

Figure 2: Left Side Panel Adjustments

2.5.1.1 ALERT LEVEL

The ALERT LEVEL trimpot is used to adjust the level for the internally generated Alert signals. Other
parameters relating to these signals are adjusted from the right side panel.

2.5.1.2 S/T LEVEL

The S/T LEVEL trimpot adjusts the overall sidetone level of all selected transceivers (from the front
panel).

2.5.1.3 VOX LEVEL

The VOX LEVEL trimpot sets the sensitivity level for the front panel VOX control (the level of audio
required to activate microphones).

2.5.1.4 POWER ON

The POWER ON LED will illuminate to indicate that the unit is connected to the power supply.

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

2.5.2 Right Side Panel Adjustments

A variety of different signals can be selected to trigger the internal Alert signals. The trimpots on the right
side panel shown in Figure 3 are used to adjust the characteristics of the audible signals that the user will
hear.

Figure 3: Right Side Panel Adjustments

2.5.2.1 DIR AUD LEVEL

The DIR AUD LEVEL trimpot is used to adjust the audio level of the devices connected to the DIR AUD 1
input.

2.5.2.2 AUDIO ALERTS

AUDIO ALERT 1 is a single tone signal and AUDIO ALERTS 2 and 3 are two-tone signals.

2.5.2.3 TIME

The duration of AUDIO ALERT 3 can be adjusted from one to three seconds using the TIME trimpot.

2.5.2.4 TONE

The pitch of the signals can be adjusted using the relevant TONE trimpot.

2.5.2.5 RATE

The cycling rate of the two-tone signals can be adjusted using the RATE trimpot s.
Note: The number and type of adjustments is dependent on the features specific to the particular AA95,

AA96 or AA97 configuration.

2.6 Accessories Required But Not Supplied

Installation kit p/n AA90-IKC (crimp) (NAT Part No. D50S37SL-IKC) is required to complete the
installation. The kit consists of one 50-Pin D-min Female Crimp Kit (D50SL-IKC) and one 37-Pin D­min Female Crimp Kit (D37SL-IKC):

D50SL-IKC consists of

Quantity Description NAT Part No.

1 D-min 50 Socket Housing 20-21-050
50 MS Crimp Socket 20-26-901
1* Jack Screw Set 20-27-002
1* Lock Clip Set 20-27-004
1 50 Pin Connector Hood 20-29-051

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

D37SL-IKC consists of

Quantity Description NAT Part No.

1 D-min 50 Socket Housing 20-21-037
37 MS Crimp Socket 20-26-901
1* Jack Screw Set 20-27-002
1* Lock Clip Set 20-27-004
1 37 Pin Connector Hood 20-29-038
* Use as required.

2.7 Installation Drawings

Note: There are multiple versions of the AA95, AA96 and AA97. For this reason, the documents listed

below are supplied for reference only for units with Serial numbers 6000 and above. If specific
model information is required, please contact the Product Support Department at NAT.

DOCUMENT REV. DESCRIPTION TYPE
AA95 and AA96 (All versions)

AMS43\922-0 1.01 Audio Controller Mechanical Installation

AA95-728

AA95\728\403-0 1.01 Audio Controller Interconnect
AA95\728\403-1 1.01 Audio Controller Interconnect
AA95\728\403-2 1.01 Audio Controller Interconnect
AA95\728\405-0 1.01 Audio Controller Connector Map
AA95\728\905-0 1.02 Audio Controller Faceplate

AA95-729

AA95\729\403-0 1.00 Audio Controller Interconnect
AA95\729\403-1 1.02 Audio Controller Interconnect
AA95\729\403-2 1.01 Audio Controller Interconnect
AA95\729\405-0 1.02 Audio Controller Connector Map
AA95\729\905-0 1.02 Audio Controller Faceplate

AA96-001

AA96\001\403-0 1.00 Audio Controller Interconnect
AA96\001\403-1 1.00 Audio Controller Interconnect
AA96\001\403-2 1.00 Audio Controller Interconnect
AA96\001\405-0 1.00 Audio Controller Connector Map
AA96\001\905-0 1.11 Audio Controller Faceplate

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AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

DOCUMENT REV. DESCRIPTION TYPE
AA96-400

AA96\400\403-0 1.01 Audio Controller Interconnect
AA96\400\403-1 1.01 Audio Controller Interconnect
AA96\400\403-2 1.01 Audio Controller Interconnect
AA96\400\405-0 1.01 Audio Controller Connector Map
AA96\400\905-0 1.11 Audio Controller Faceplate

AA97-402

AA97\402\403-0 1.02 Audio Controller Interconnect
AA97\402\403-1 1.02 Audio Controller Interconnect
AA97\402\403-2 1.02 Audio Controller Interconnect
AA97\402\405-0 1.01 Audio Controller Connector Map
AA97\402\905-0 1.11 Audio Controller Faceplate
AA97\402\922-0 1.00 Audio Controller Mechanical Installation

Section 2 ends following the above documents

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RX-ON

RX-ON

NAV1

NAV1

DME

DME

ADF

ADF

AA95

AA95

-728

-728

COM

COM

1

1

//

ISOISO EMREMR

NORMAL

NORMAL

COM

COM

2

2

TX

TX

FM1 FM2

FM1 FM2

LIVE COM1

LIVE COM1

NAV2AUX

NAV2AUX

PA

PA

MKR

MKR

ICS

ICS

VOX

VOX

KEY

KEY

MUSIC

MUSIC

ICS

ICS

CALL

CALL

RX VOL

RX VOL

ICS VOL

ICS VOL

Confidential and Proprietary to NAT

Confidential and Proprietary to NAT

Confidential and Proprietary to NAT

TX 5TX 4TX 3TX 2TX 1

TX 5TX 4TX 3TX 2TX 1

AA96

-001

-001

TOWERAA96

TOWER

ICS

ICS

TIE

TIE

SPLIT

SPLIT

TX

TX

VOX

VOX

PA

PA

VOX

VOX

LIVE

LIVE

ICS

ICS

VOL

VOL

MASTER

MASTER

VHF1

VHF2

TAC1

TAC2

TAC3

TAC4

AA97

-402

0 10

0 10

0 10

RX-ON

VHF

/

ISO EMR

NORMAL VHF1

VHF

1

2

TX

TAC TAC3TAC

21

PA

TX

0 10

TAC

4

0 10

NAV1

NAV2 DME

LIVE

ADF

ICS

VOX

KEY

0 10

RX VOL

ICS VOL

AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

Section 3 Operation

3.1 Introduction

Information in this section consists of functional and operational procedures for the AA9x Series Single
Channel Audio Controller.

Note: The AA95, AA96 and AA97 series single channel audio controllers are customized units, and may

have unique operational features that are different to the options described, or are not covered in
this manual. Any questions should be directed to the NAT Product Support Department.

3.2 General Information

Figure 1: AA9x Operator Accessible Controls

The AA9x provides control for all aircraft audio, allowing selection of transmit and receive audio, LIVE,
KEYED, or VOX intercom and interface for an additional hand held transmit microphone (hand mic). The
AA95 and AA97 series of audio controllers allow selection of pilot isolation/emergency operation.

Sidetone level is adjustable internally, while receive (RX) and intercom (ICS) levels are adjustable on the
front panel. In most AA9x configurations, all audio (except the sidetone of the radio in use) is muted
during transmit for clarity. In the AA95 and AA97 series of controllers, the directly connected DIRECT
AUDIO 2 input signal (see Section 3.6.1) remains un-muted during transmit. ICS operation will allow
transmit during any ICS mode by using the PTT switch.

3.3 Controls and Indicators

In all AA9x controllers, transmit and PA functions are controlled with a single rotary selector switch, or (in
some configurations) with the TX/PA Select switch. The main receive volume, ICS volume and ICS VOX
squelch are individually adjusted with rotary controls. The ICS operations and receive audios are selected
using color-coded toggle switches. In the AA95 and AA97 controllers, individual receive audio is selected
with color-coded toggle switches. In the AA96 and AA97 controllers, individual receive volumes are
adjusted using rotary controls.

Section 3 Rev: 1.00 Issue 4 Page 3-1

ENG-FORM: 806-0111.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

3.3.1 Receive Audio Select Switches

Radio Specific Volume Controls

(AA97 only)

Transceiver

Receive

Audio

Switches

NAV
Receive
Audio
Switches

Receive

Volume

Control

Mode Switch

TX/PA Select Switch

Figure 2: Receive Audio Select Switches

The transceiver receive audio select switches (white switch bats) are two position switche s. When set to
the ‘up’ position, the respective transceiver receive audio is selected on. When set to the ‘down’ position,
the respective transceiver receive audio is selected off.

The NAV receive audio select switches (blue switch bats) are typically three position switches. When set
to the ‘up’ or ‘down’ position, the respective NAV receive audio is selected on. When set to the ‘center-off’
position, the respective NAV receive audio is selected off.

The master receive volume control (RX VOL) adjusts all receive audio concurrently from 1% to full. It is
important to set the individual radio volume controls to a nominal level and then use the master receive
volume on the audio controller to adjust for changing flight conditions.

When the red mode switch is set to NORMAL (AA95 and AA97’s only), the passengers will hear the radio
audio as selected on the controller. The passengers will not hear any radio audio when the red mode
switch is in the ISO/EMR position.

Section 3 Rev: 1.00 Issue 4 Page 3-2

ENG-FORM: 806-0111.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

3.3.2 Transmit Selector Switch

TX Indicator

Figure 3: Transmit Select Switch

The transmit selector switch is a six posi t i on switch used to select the desired transceiver. For the AA95
and AA96, this switch typically selects the PA function when rotated fully clockwise. When the hand mic
or transmit PTT switch is activated, the mic will be coupled to the radio (or PA) selected. The pilot has
priority over the copilot during transmit operations.

Receive audio for the transceiver selected is automatically activated as a function of the rotary selector
switch and no additional switching is needed to establish outside communication. During transmit, all
audio selected is muted except the sidetone of the transceiver in use. In the AA95 and AA97’s, Direct
Audio 2 also remains un-muted during transmit.

The front panel TX indicator will illuminate green when either the pilot or co-pilot transmits. It will not light
when the hand mic (if installed) is used.

3.3.3 ICS Functions

Intercom audio may be implemented in three modes: LIVE (on constantly), VOX (voice activated), or
KEYED (active only when switched by ICS PTT switch). It is common to use the LIVE mode during
ground operations, start-up, etc. and to use VOX or KEYED operation if conditions are so noisy that ‘pilot
fatigue’ will result.

Transmit Selector Switch

Mode Switch

VOX Squelch

Control

ICS Mode Switch

ICS Volume

Control

Figure 4: ICS Switches

Section 3 Rev: 1.00 Issue 4 Page 3-3

ENG-FORM: 806-0111.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

3.3.3.1 LIVE (Hot Mic Operation)

ICS mode switch (orange switch bat) set to the up (VOX) position and the VOX squelch control set to the
full counter-clockwise position.

3.3.3.2 KEYED ICS (PTT Operation)

ICS toggle switch (orange switch bat) set to the down (KEY) position. In some models of AA9x audio
controllers, set the VOX squelch control to the full clockwise position. Keyed ICS is inherent to the pilot
and copilot microphone circuits only. Passenger microphone circuits will be LIVE with this mode selected.

3.3.3.3 VOX (Voice Activated)

ICS toggle switch (orange switch bat) set to the up (VOX) position. Set the ICS VOX Squelch control fully
counter-clockwise and then slowly rotate clockwise until the intercom just becomes quiet. This setting will
vary with ambient noise conditions and the quality and number of microphones connected in the system.

3.3.3.4 General ICS Functions

Passenger ICS audio is LIVE when the controller is in the LIVE or KEYED mode of ICS operation. In the
KEYED mode of operation the passenger microphones are LIVE. Utilize drop cord assemblies
incorporating microphone circuit interrupt switches for keyed ICS operation. Passenger ICS is VOX
triggered when VOX mode is selected.

All ICS audio is controlled by the front panel ICS volume control and may be varied to suit conditions. The
ICS VOL control provides adjustment from approximately 1% to full output.

In the AA95 and AA97 models the mode switch (red switch bat) is used to select between NORMAL and
PILOT ISO/EMR modes. In the NORMAL position (down), all operations of the ICS are functional as
described above. When the switch is in the pilot isolate/emergency position (PILOT ISO/EMR), the pilot is
isolated from the rest of the passengers. If the controller is operated in the ISO/EMR mode, ICS operation
will continue (if there is no fault condition) between the passengers and copilot, but will exclude the pilot.
See Section 3.5 for further details.

3.4 Optional Features

Some of the more common optional features can be seen on the AA95-728 (shown in Figure 4, section

3.3.3) and Figure 5 below.

Figure 5: AA95-729

Section 3 Rev: 1.00 Issue 4 Page 3-4

ENG-FORM: 806-0111.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

3.4.1 ICS ISO and/or PLT ISO Annunciators

ICS ISO and/or PLT ISO annunciators indicate that the intercom connection to the other audio controllers
(typically the pilot’s) has been switched off.

3.4.2 ICS CALL Annunciator

ICS CALL annunciator indicates that an ICS CALL switch is active and that the intercom connection
between the audio controllers needs to be restored.

3.4.3 ICS CALL Switch

ICS CALL switch used to signal other audio controllers (typically the pilot’s) that an ‘isolated’ station
needs to communicate with the pilot(s). The output from the switch is normally used to activate a CALL
annunciator and/or a CALL tone.

3.4.4 PAT ON/OFF Switch

PAT ON/OFF (Patient Headphone Audio Select) switch allows the crew to select the patient audio ON or
OFF.

3.4.5 ICS TIE/SPLIT Switch

ICS TIE/SPLIT switch allows for local selection of the intercom connection to other audio controllers in the
aircraft intercom system. In the TIE position, intercom audio is shared with all other audio controllers. In
the SPLIT position, intercom audio to/from all other audio controllers is deselected.

3.5 Emergency Operation (AA95 and AA97 models only)

When the red PILOT ISO EMR/NORMAL mode switch is set to the ISO/EMR position, the pilot is
removed from the ICS bus and connected directly to the selected radios. This mode should be selected in
the event of a box fault or power failure.

In the ISO/EMR mode, all functions are retained by the pilot, except ICS and possibly boom mic
operation. If the box or airframe fault prevents the TX annunciator from lighting during transmit (indicating
a failure in the mic keying circuit), then the hand mic should be used. A power fault of any kind will
prevent the TX annunciator from lighting, giving an immediate indication of failure. If ICS audio is still
available, then the power to the controller has not failed, and loss of the TX light indicates TX switch
failure.

In the ISO/EMR mode, all switches work exactly as they do during NORMAL operation, except for the RX
and ICS volume controls, which have no effect. The ISO/EMR function should be tested prior to flight to
ensure proper operation and allow the radio levels to be set adequately for emergency operation.

Any selected receive audio is switched to the primary user (pilot) in the ‘emergency’ mode, but not to any
passengers in the system. Audio level will be lower than in NORMAL operation because the signals are
obtained directly from the radios, bypassing the electronics in the controller. This is provided for failure
situations that make operation impossible in the NORMAL mode (i.e. loss of power or amplifier failure, etc.).

Section 3 Rev: 1.00 Issue 4 Page 3-5

ENG-FORM: 806-0111.DOT

CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.

AA9x Series Single Channel Audio Controller

SM56 Installation and Operation Manual

3.6 Audio Alerting Functions (AA95 and AA97 models only)

Two types of audio alerting are supported, Direct Audio and Internal Alerting. The use of these alerting
features should be determined, defined and recorded so that the operator has an opportunity to use these
features as they were intended for their specific installation.

3.6.1 Direct Audio

Direct Audio is when an audio signal from an existing warning system is connected ‘directly’ into the audio
system and is not front panel selectable. There are usually two Direct Audio inputs on the AA95 and
AA97. Typically, Direct Audio 1 is an amplified/adjustable input and Direct Audio 2 input connects directly
to the pilot's headset output.

3.6.2 Internal Alerting

Internal Alerting is provided by up to three separate, internal tone generators that are coupled to the
headset output. These tones are a function of the AA95 or AA97 itself and can be used to supplement
existing warning tones (Low Rotor, Engine Out warnings in a Bell 206) or provide unique alerting
capability for functions such as ICS Call, Rad Alt DH warning, etc. The internal alerts are configuration
specific and how they will be used is determined at the time of installation. The Internal alerts are not front
panel selectable.

Section 3 ends

Section 3 Rev: 1.00 Issue 4 Page 3-6

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CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIR BORNE TECHNOLOGY LTD.