Bose A20 Service Manual

The Bose A20 Aviation Headset is a premium active noise-canceling headset designed for pilots and aviation professionals. It features advanced noise reduction technology, Bluetooth® connectivity for communication and audio, comfortable headband and ear cushions, auxiliary audio input, and compatibility with various aircraft intercom systems. Below are key sections for safety, features, installation, setup, operation, maintenance, and troubleshooting.

1. Features at a Glance 2. Installation 3. First-Time Setup 4. Specifications 5. Controls and Settings 6. Connecting to Aircraft Systems 7. Using Bluetooth® Connectivity 8. Maintenance & Cleaning 9. Regulatory Information 10. Troubleshooting

Features at a Glance

Key components: Headset with integrated control module, Dual ear cups with noise-canceling microphones, Bluetooth® module, Aircraft plug (dual or single), Carrying case, Audio cable.

Feature	Description
Active Noise Reduction	Electronically reduces ambient cockpit noise
Bluetooth® Connectivity	Wireless connection for phones and audio devices
Control Module	Volume, mute, Bluetooth pairing, auxiliary input
Aircraft Plug	Standard aviation connectors (U174, U94A)
ComfortFit Headband	Padded, adjustable headband for extended wear
Ear Cushions	Replaceable gel/foam cushions for noise isolation
Auxiliary Audio Input	3.5mm jack for external audio sources
Battery Compartment	Houses AA batteries for power (approx. 45 hours)
Microphone Boom	Flexible, noise-canceling electret microphone
Carrying Case	Protective case for storage and transport

Installation

Unpack and inspect contents. Ensure all components are present.

Insert batteries: Open battery compartment, insert two AA batteries observing polarity.
Connect to aircraft: Plug aviation connector into aircraft jack panel.
Position headset: Place headset on head, adjust headband for comfort.
Position microphone: Adjust boom so microphone is close to mouth.

WARNING! Do not use headset if cords are frayed or damaged. Ensure aircraft power is within specified limits.

First-Time Setup

Power on headset; verify operation.

Power on: Slide power switch to ON position; green LED should illuminate.
Test communications: Transmit and receive to verify audio clarity.
Pair Bluetooth® device: Press and hold Bluetooth button until LED flashes blue, then search on your device.
Adjust settings: Use control module to set volume, sidetone, and audio priorities.

CAUTION! Ensure headset is not tangled or pinched in aircraft seat or controls.

Specifications

Noise Reduction: Active noise reduction up to 30 dB.
Frequency Response: 50 Hz – 20 kHz.
Microphone: Electret noise-canceling, flexible boom.
Connectors: Standard aviation plugs (U174/U94A), 3.5mm auxiliary input.
Bluetooth®: Version 3.0, supports A2DP and HSP profiles.
Power Source: Two AA batteries (alkaline or lithium).
Battery Life: Approximately 45 hours with ANR on.
Weight: 12 ounces (340 grams).
Operating Temp: -10°C to 50°C (14°F to 122°F).

Controls and Settings

Access functions via control module on cord. Power Switch: ON/OFF. Volume Knob: Adjusts headset volume. Mute Button: Mutes microphone. Bluetooth® Button: Initiates pairing and controls calls. Auxiliary Input: 3.5mm jack for music/navigation audio.

LED Indicators: Green (power on), Flashing Blue (Bluetooth pairing), Red (low battery).

Audio Priority: When both Bluetooth and aircraft comms are active, priority can be set for communications. Sidetone Control: Adjust level of own voice in headset (if supported by aircraft intercom).

Connecting to Aircraft Systems

Standard aviation jacks: Dual plug (U174) for pilot, single plug (U94A) for copilot.

Ensure aircraft avionics master is OFF before connecting.
Insert plug firmly into aircraft jack; ensure it clicks into place.
Turn on avionics master and radio systems.
Test transmit and receive functions.

Tip: For helicopters or noisy environments, ensure ANR is activated for optimal performance.

Using Bluetooth® Connectivity

Supports wireless connection to smartphones and tablets for calls and audio streaming.

Pairing: Press and hold Bluetooth button until LED flashes blue. Enable Bluetooth on your device and select "Bose A20".
Answering calls: Press Bluetooth button once to answer; press again to end.
Audio streaming: Play audio from device; volume controlled via headset or device.
Disconnect: Turn off Bluetooth on device or power off headset.

WARNING! Do not use Bluetooth for critical communications; primary comms should be via aircraft radio.

Maintenance & Cleaning

Regular maintenance ensures optimal performance and longevity.

Ear cushions: Wipe with damp cloth; replace if torn or hardened.
Microphone windscreen: Remove and clean with mild soap and water; air dry.
Cords and plugs: Inspect for damage; clean with dry cloth.
Storage: Store in carrying case in a cool, dry place.

CAUTION! Do not immerse headset in water. Do not use solvents or abrasive cleaners.

Regulatory Information

FCC Part 15: Class B digital device; complies with interference limits. Bluetooth® is a trademark of Bluetooth SIG, Inc. Copyright © Bose Corporation. For support, visit www.bose.com/aviation or contact Bose Aviation Headset Division. This device complies with Part 15 of the FCC Rules.

Troubleshooting

Symptom	Possible Cause	Corrective Action
No power/ANR not working	Dead batteries	Replace with fresh AA batteries.
No audio from aircraft	Loose connection, volume low	Check plug connection; increase volume on headset and panel.
Microphone not transmitting	Mute activated, boom position	Check mute button; reposition microphone closer to mouth.
Bluetooth not pairing	Out of range, pairing mode not active	Ensure headset is in pairing mode (flashing blue); move device closer.
Intermittent audio	Damaged cord, interference	Inspect cord for damage; ensure plugs are clean and secure.

Reset: Power off headset, remove batteries for 30 seconds, reinsert and power on.

Service: For repairs, contact authorized Bose service center. Do not attempt to disassemble headset.