Light Aircraft Radio Equipment E-Book

Askhat Khafizow

• Herausgeber: Askhat Khafizow
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Veröffentlichungsjahr: 2024

Beschreibung

There is a wide range of radio equipment installed on light aircraft that can be used by pilots when flying under Instrument Flight Rules (IFR). This reference guide provides information on the most commonly used equipment.The radio equipment is considered in terms of its purpose and operating principle. If the equipment is part of a system, such as a navigation system, the system as a whole discussed first, followed by the specific aircraft equipment. The functions of the controls and the issues related to the operation of the equipment are discussed according to its circuit design.This reference guide can be useful not only for pilots but also for flight school students as a study guide.

Leseprobe

Askhat Khafizow

Light Aircraft

Radio

Equipment

Pilot's Reference Guide

for IFR Flight

2024

© Askhat Khafizow, 2024

All rights reserved.

Askhat Khafizow

Ukraine, Kropyvnytsky

[email protected]

ISBN 9783689952082

No part of this book may be reproduced in any form or by any electronic or mechanical means, including information storage and retrieval systems, without permission in writing from the publisher.

The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

CONTENTS      

INTRODUCTION

1. INTERCOM SYSTEMS

1.1 Intercom Purpose and Operation

1.2 Garmin GMA-340

1.3 Bendix King KMA 26 Audio Control Panel

1.4 Garmin GMA-345Audio Control Panel

1.5 PS Engineering PMA 7000M-SAudio Control Panel

1.6 Garmin-1000 Radio components

1.6.1 GMA 1347 Audio Control Panel in Garmin 1000

2. EXTERNAL COMMUNICATION EQUIPMENT

2.1 Basic Provisions

2.1.1 Radio Channel Principle of Operation

2.1.2 VHF Radio Station Operating Features

2.1.3 HF Radio Station Operating Features

2.2 VHF Radios in Garmin 1000

2.3 KHF-950 HF Radio

3. NAV/COM EQUIPMENT

3.1 VOR Channel Basic Provisions

3.1.1 VOR Channel Principle of Operation

3.1.2 VOR Equipment Indicators

3.1.3 VOR Channel Specifications and Features of Use

3.2 ILS Channel Basic Provisions

3.2.1 Course (Localizer) Channel Principle of Operation

3.2.2 LOC Channel Specifications

3.2.3 Glide Slope Channel Principle of Operation

3.2.4 Glide Slope Channel Specifications

3.2.5 Marker Channel Purpose and Principle of Operation

3.3 BENDIX KING KX 155 NAV/COM

3.4 BENDIX KING KX 165 NAV/COM (GS)

3.5 BENDIX KING KN 53

3.6 NAV Equipment in Garmin 1000

4. DISTANCE MEASURING EQUIPMENT

4.1 DME Channel Principle of Operation

4.2 BENDIX KING KN 62A DME

4.3 BENDIX KING KN 63 with KDI 573 INDICATOR

4.4 KN63 DME in Garmin 1000

5. AUTOMATIC DIRECTION FINDER

5.1 ADF Basic Provisions

5.1.1 ADF Principle of Operation

5.1.2 Factors Influencing Accuracy

5.2 BENDIX KING ADF KR 87

5.3 ADF KR-87 in Garmin 1000

6. SATELLITE NAVIGATION SYSTEM RECEIVER

6.1 SNS Channel Principle of Operation

6.2 GNSS receiver in Garmin 1000

7. AIRCRAFT TRANSPONDERS

7.1 ATC RBS Basic Provisions

7.1.1 ATC RBS Principle of Operation

7.1.2 Transponder Operating Modes

7.2 Bendix King KT-76C Mode “C” Transponder

7.3 Bendix King KT-73 Mode “S” Transponder

7.4 Garmin GTX 327 Mode “C” Transponder

7.5 Garmin GTX 330 Mode “S” Transponder

7.6 GTX 33ES Transponder in Garmin 1000

8. AIRBORNE SURVEILLANCE EQUIPMENT

8.1 TAS Equipment

8.1.1 TAS System Basic Provisions

8.2 TAS Equipment in Garmin 1000

8.2.1 TAS Equipment Control and Setting Procedure

8.3 ADS-B Equipment

8.4 TIS-B Equipment

8.4.1 TIS-B System Principle of Operation

9. AIRBORNE WEATHER RADAR

9.1 Airborne Weather Radar Principle of Operation

9.1.1 Radar Operating Modes

9.2 RDR-2000 / ART-2000 Radars

9.3 RDR-2100 / ART-2100 Radars

9.4 GWX 68 / GWX 70 Radars in Garmin 1000

10. STORMSCOPE DETECTION SYSTEM

10.1 Stormscope Basic Provisions

10.2 WX-1000 Stormscope

10.3 WX-500 Stormscope in Garmin 1000

11. RADIO ALTIMETERS

11.1 Radio Altimeter Basic Provisions

11.1.1 Radio Altimeter Principle of Operation

11.2 KRA 405B Radio Altimeter

11.3 KRA 405B in Garmin 1000

12. EMERGENCY BEACONS (ELT)

12.1 ELT Basic Provisions

12.2 Artex ELT ME406 / Artex ELT C406-N

13. GDL-69A IN GARMIN 1000

List of abbreviations

References

INTRODUCTION

For over half a century of light aircraft existence, the radio equipment installed on such aircraft has undergone significant changes in its technical characteristics, functional tasks, operating principles, component base, and control panel design. Additionally, there has been a shift in the systematic approach to the layout and installation of this equipment on the aircraft.

Thus, the previous layout entailed installing all control panels on the cockpit dashboard (Figure 1), with the capability to display navigation parameters measured by onboard equipment on dedicated indicators. Combined-type indicators were also utilized to display two or three parameters simultaneously.

1, 7 - Audio Panel; 2, 3, 8, 9 - COM/NAV Control Panel; 4, 11 - DME Control Panel;

5, 12 - Transponder Control Panel; 6, 10 - ADF Control Panel

Figure 1 - Options of avionics panel radio rack on Cessna:

The new, more integrated approach is characterized by a fully display-oriented equipment layout, encompassing both parameter display and equipment control directly from the display panel (Figure 2).

Figure 2 - Display-oriented Equipment Layout

Also possible are combined layout options, where the display-oriented layout is supplemented by various equipment aimed at performing specific functions, such as navigation parameter determination, data transmission, or enhancing the pilot's situational awareness.

Thus, there is a wide range of radio equipment installed on light aircraft that can be used by pilots when flying under Instrument Flight Rules (IFR).

This reference guide provides information on the most commonly used equipment.

The radio equipment is considered in terms of its purpose and operating principle. If the equipment is part of a system, such as a navigation system, the system as a whole is discussed first, followed by the specific aircraft equipment.

The functions of the controls and the issues related to the operation of the equipment are discussed according to its circuit design.

Overall, aircraft radio equipment includes:

(a) Intercom systems - for transmitting voice messages on board the aircraft;

(b) External communication equipment (radios) - for radio communication with ATC;

(c) Radio navigation equipment - for measuring the navigational parameters of the aircraft's position and flight parameters;

(d) Airspace surveillance systems - for assessing meteorological and air traffic conditions near the aircraft;

(e) and others.

Therefore, in this reference guide, radio equipment is considered according to this list.

This reference guide can be useful not only for pilots but also for flight school students as a study guide.

Comments regarding this publication should be sent, in email form, to the following address: [email protected].

1. INTERCOM SYSTEMS

1.1. Intercom Purpose and Operation

The intercom system is provided:

- The transmission of voice messages between pilots, and between crew and passengers;

- Transmitting announcements to passengers;

- Radio communication with air traffic control (ATC) via on-board radio stations;

- Monitoring of ground beacons call signs;

- Monitoring special sounds and voice messages generated by on-board systems.

Typically, an intercom system consists (Figure 1.1) of headsets (which include microphones and headphones), a loudspeaker, shift keys (commonly referred to as “PTT”), and an audio control panel (ACP).

a) Headset; b) Loudspeaker; с) “PTT” key on the control wheel; d) Audio Control Panel

Figure 1.1 – Intercom system composition:

The Audio Control Panel (ACP) serves as the central component of the intercom system. It functions as a switching device, allowing the pilot to link the headset components (microphone and headphones) to the radio stations and the output of radio navigation receivers, as well as to adjust intercom channels and perform other necessary actions.

Figure 1.2 illustrates a schematic diagram of the audio control panel.

Figure 1.2 – Schematic diagram of the audio control panel

The ACP incorporates several key features, including:

1) VOX (Voice Operated Exchange) technology

VOX technology allows for hands-free communication between pilots without the need to press the “PTT” key (as depicted in Figure 1.2). In this setup, the microphone circuit connects directly to the Low-Frequency Amplifier (LFA1 or LFA2). The volume of the speaker can be adjusted using the “VOL” (Volume) knob. A functional indicator of normal operation is if the pilot can hear themselves through the intercom system.

However, a drawback of VOX technology is the potential for background noise of the cockpit or engine operations to be audible in the pilot's headphones. Various methods exist to mitigate this issue.

One such method is the amplitude method, which operates on the assumption that the amplitude of the combined signal (speech plus noise) exceeds that of the noise signal alone. The operational principle of this method is depicted in Figure 1.3 (a, b).

Noise suppression is achieved through the comparison circuit, specifically the Amplitude Comparator, and the electronic key (EK), which has two states: open and closed. When the amplitude of the noise signal generated by the microphone is below the squelch threshold set by the pilot using the “Squelch” knob (Figure 1.3, a), the contacts of the electronic key are opened. Conversely, if the total signal level (speech + noise) exceeds the noise suppression threshold (Figure 1.3, b), the contacts are closed, allowing the voice message signal to pass to the Preamplifier of the intercom system.

a) b)

Figure 1.3 – VOX technology principle of operation

Adjusting the noise reduction threshold (NRT) involves the following procedure with the “Squelch” knob:

- Turn the knob to the left (counter-clockwise) until it stops, then slowly turn it to the right until background noise becomes audible in the headphones;

- Then, turn the knob slightly to the left until the background noise disappears;

- Confirm that there is no noise in the headphones;

- Speak into the microphone and ensure that the transmission is audible.

Note: In more advanced versions of VOX technology systems, the noise reduction threshold can be set automatically, based on the noise level detected in the cockpit.

2)Loudspeaker Communication System

The loudspeaker system in light aircraft facilitates communication between the pilot and passengers throughout the flight.

Typically, this system includes the following components:

- Pilot's Microphone: This microphone can be integrated into the headset or exist as a separate unit with a “PTT” key on its body (as depicted in Figure 1.4).

- Speaker Amplifier (LFA Speaker): This component amplifies audio signals for transmission through the speakers.

- Passenger Speaker: If configured, this speaker allows passengers to hear communications from the pilot.

- Control Panel (Audio Panel): The control panel facilitates the management of the loudspeaker communication system.

Figure 1.4 - Loudspeaker Communication System

Generally, a loudspeaker communication system is interconnected with the Intercom telephone communication system. When making announcements using a headset microphone, the pilot must first press the “PA” (Public Address) button on the control panel. Subsequently, pressing the “PTT” key on the control wheel ensures that the audio signal of the voice message is not transmitted to the radio station but is instead routed through the amplifier (LFA Speaker) to the passenger speaker.

In light aircraft with a limited number of passenger seats (typically no more than four), the cabin loudspeaker may serve both passengers and pilots (as illustrated in Figure 1.2).

In certain aircraft, the loudspeaker may be connected to the output of radio equipment receivers. When the “SPKR” button on the control panel is activated, the signal from the receiver selected by the pilot is directed to the loudspeaker amplifier (LFA Speaker). Receiver selection for listening is controlled from the control panel.

Notes:

1) The passenger speaker can be used to broadcast audio entertainment programs.

2) During announcements to passengers, the volume of other messages played through the speaker is either reduced or completely muted.

3) External Communication (Radio)

Radio communication with Air Traffic Control (ATC) is facilitated through a radio station installed on the aircraft. In light aircraft, multiple radio stations may be installed, allowing for flexibility in communication. Selection of the desired station for communication is achieved from the audio control panel by pressing the corresponding button (“COM 1 MIC”, “COM 2 MIC”, or “COM 3 MIC”).

When a button is pressed, the headphones are connected to the output of the receiver of the selected station. Additionally, it is possible to separately connect the headphones to the receiver of another radio station by pressing the corresponding button (“COM 1”, “COM 2”, or “COM 3”).

To transmit a message, the pilot must press the “PTT” key. The schematic in Figure 1.2 illustrates that pressing the “PTT” key connects the microphone to the transmitter of radio station COM1 (indicated by the backlight of the “COM 1 MIC” button being illuminated). Simultaneously, it connects the headphones to the output of the receivers of radio stations COM1 and COM2 (indicated by the “COM2” button being pressed and the backlight of the “COM 1” and “COM 2” buttons being lit, with contacts K2 and K3 being closed).

Notes:

1) When the “PTT” key is pressed, the microphone circuit is disconnected from the intercom system, allowing the pilot to hear their transmission only through the selected radio station.

2) Pressing the “PTT” key also initiates the transmitter start circuit of the chosen radio station and connects the antenna (not depicted in the schematic).

3) Connection status is indicated by the LED of the corresponding button being illuminated. Pressing the button again deactivates the connection, and the LED turns off.

4) The “Split COM” Function

The “Split COM” function enables pilots to operate independently on separate radio stations, with the pilot using COM 1 and the copilot using COM 2.

5) Listening to Beacon Identification Signals

Each ground navigation radio beacon emits a unique identifier or call sign, typically in Morse code consisting of two or three letters. This identifier allows onboard navigation equipment to differentiate between beacons.

To listen to the call sign, the pilot needs to connect the headphones to the output of the navigation receiver. In Figure 1.2, pressing buttons such as “MKR/MUTE”, “NAV 1”, “NAV 2”, “DME”, or “ADF” closes contacts “K1”, “K5”, “K6”, “K7”, or “K8”, respectively, thereby connecting the headphones to the corresponding receiver. Pressing the button again disconnects the headphones.

Working with a Marker Receiver (MKR), which is part of the audio panel, has its own features.

Note: Marker receivers (MKR) are utilized to receive signals emitted by ground marker beacons, which are part of the Instrument Landing System (ILS) (as shown in Figure 1.5).

When passing over a ground marker beacon (outer, middle, or inner), the control panel indicates “O” (OUT), “M” (MIDDLE), or “I” (IN), and the pilot hears a low-frequency tone (marker audio) at 400 Hz, 1300 Hz, or 3000 Hz, respectively.

The light and marker audio correspond to a specific manipulation code: 2 dashes/second for an outer marker, alternating dashes and dots for a middle marker, and 6 dots/second for an inner marker.

Figure 1.5 – Onboard Indicators During Marker Beacon Overflight

During landing, it's possible to temporarily mute the audio output of the marker receiver. If the “MKR/MUTE” button is pressed while a marker signal is being received, the audio will be muted, but the marker indicators (“O”, “M”, or “I”) and the LED on the “MKR/MUTE” button will remain illuminated. The audio will automatically be restored when the aircraft passes the next beacon.

This function of the marker receiver operation is referred to as the “Smart MuteTM” function.

6) Intercom Modes (Isolation Modes)

There are three intercom modes, also known as isolation modes:

- “PILOT” mode: In this mode, the pilot is isolated from intercom communication, while the copilot and passengers are isolated from accessing external communications. However, passengers can still communicate with each other.

- “CREW mode: In this mode, both pilots have access to external communications, but they are isolated from passenger communications. Passengers can only communicate with each other.

- “ALL” mode: In this mode, both pilots and passengers can communicate freely and listen to external communications.

7) Automatic Connection in Power Failure

In the event of a power failure, blackout, or if the audio panel is switched off, the pilot's headset will automatically connect to the COM1 radio station.

1.2. Garmin GMA-340

Garmin GMA-340 Equipment Set

Garmin GMA-340 equipment set includes the following components:

- “PTT” keys (two) are located on both control wheels (see Figure 1.6, a).

a) b)

Figure 1.6 – “PTT” key (a) and a Loudspeaker (b)

- Loudspeaker (one) is positioned on the center overhead console (see Figure 1.6, b).

- Aviation headsets are provided for the pilots and each of the passengers in their respective places.

- Audio Control Panel (one) is situated on the cockpit instrument panel (see Figure 1.7).

Figure 1.7 – Audio Control Panel on the cockpit instrument panel

- Marker receiver (one) is integrated into the ACP unit.

- Marker beacon antenna (one) is mounted at the bottom of the tail fairing (see Figure 1.8).

Figure 1.8 – Marker Beacon Antenna

- Pilot headset connectors (two) (see Figure 1.9)are located under the instrument panel (left and right).

Figure 1.9 – Pilot headset connectors

The intercom system is powered by direct current with a voltage of 28 V. The power circuits are safeguarded by a fuse labeled “AUDIO” on the Switch Panel (see Figure 1.10).

Figure 1.10 – The Switch Panel

Garmin GMA-340 Audio Control Panel

The Audio Control Panel (ACP) of the Garmin GMA-340 is equipped with the following controls (refer to Figure 1.11 and Table 1.1).

Figure 1.11 – GARMIN GMA-340 Audio Control Panel

Table 1.1 – GARMIN GMA-340 Purpose of Controls

Pos.

Form

Name, Purpose

1

“PILOT” Inner Knob:

- To activate the audio panel (by rotation the knob clockwise until it clicks) and to adjust the volume in the pilot's headset.

2

“PILOT” Outer Knob:

- To adjust the noise reduction threshold (from the pilot side) by pressing and rotation the knob. To return, press the knob again.

3

“COPILOT” Inner Knob:

- To adjust the volume of the copilot`s headset (in pressed position) or the passengers` headsets (in extended position).

4

“COPILOT” Outer Knob:

- To adjust the noise reduction threshold (from the copilot and passengers’ side) by pressing and rotation the knob.

- To return, press the knob again.

5

Radio Station Selection Buttons:

- To select a radio station: COM 1, COM 2 or COM 3 (for transmission).

- When the button is pressed, its backlight illuminates.

- During transmission, the backlight flashes at approximately 1 Hz.

6

Receiver Selection Buttons:

- To connect headphones to the radio's receiver output.

7

“COM 1/2” or “Split COM” Function Button:

- To separate operation on radio stations: the pilot on COM1 and the copilot on COM2.

- When the “COM 1/2” button is pressed, the illumination of five buttons is activated: “COM 1/2”, “COM 1 MIC”, “COM 1”, “COM 2 MIC”, and “COM 2”.

- The copilot can make announcements to the passengers over the loudspeaker by pressing the “PA” button beforehand.

Table 1.1 continued

8

“NAV1”, “NAV2” Buttons:

- To connect headphones to the navigation receiver NAV 1 or NAV 2 output.

9

“DME” Button:

- To connect headphones to the navigation DME receiver output.

10

“ADF” Button:

- To connect headphones to the navigation ADF receiver output.

11

“SPKR” Button:

- To connect the cockpit speaker to the radio receiver’s output.

12

“PA” Button

- To switch the headset microphone to the passenger speaker.

- To transmit press the “PTT” key.

13

Isolation Mode Buttons:

- To activate the isolation modes “PILOT”, “CREW” or “ALL”.

- The “ALL” mode is only activated if both “PILOT” and “CREW” buttons are not pressed.

14

“TEST” Button:

- To test all indicator lamps and LEDs (they should light up when you press and hold the button).

15

“MKR/MUTE” Button:

- To connect headphones to the marker receiver’s output

and activate the “Smart Mute” function.

16

Marker Beacon Overflight Indicators:

- Alternate on and off during overflight:

a) “O” (Outer) - Outer marker (twice per second).

b) “M” (Middle) - Middle marker (alternating long and short flashes).

c) “A” (Airway) - Inner marker (six flashes per second).

Table 1.1 continued

17

“SENS” Button:

- To switch the sensitivity of the marker receiver:

a) The “HI” indicator - high sensitivity (used during route flight).

b) The “LO” indicator - low sensitivity (used during the landing approach).

18

Photocell:

- The brightness of the button illumination varies according to lighting conditions, controlled by a photocell.

Features and Operation

1.To activate the audio panel, rotate knob 1 clockwise until it clicks.

2. To test the indicator lamps and LEDs, press and hold button 14. Ensure that all lamps and LEDs on the buttons are illuminated.

3. To adjust the volume in the pilot's headset, rotate knob 1; in the copilot's headset, press and rotate knob 3;in the passenger's headset, pull out and rotate knob 3.

4. To adjust the noise reduction threshold: from the pilot side, press and rotate button 2;from the copilot and passenger side, press and rotate button 4. To return, press the button again.

5. To select a radio station for transmission, press one of the buttons 5 and to select a receiver, press one or more buttons 6. To cancel the selection, press the button again.

6. To allow separate operation of the pilots on the radio stations, press button 7. Ensure that the “COM 1/2”, “COM 1 MIC”, “COM 1”, and “COM 2 MIC”, “COM 2” buttons are illuminated. To deactivate the “Split COM” function, press the button again.

Notes:

1) Simultaneous operation of both radios for transmission is not recommended due to mutual interference between the two radios. If both the “COM 1 MIC” and “COM 2 MIC” buttons and both “PTT” keys are pressed, transmission priority is given to the COM 1 radio.

2) In “Split COM” mode, the copilot can make announcements to the passengers. To do this, press the “PA” button and activate the transmission mode by pressing the “PTT” key on the control wheel.

7. To listen to the call signs of the ground navigation radio beacons, press the appropriate button (8, 9, or 10). To cancel, press the button again.

8. During the landing approach (before entering the marker beacon zone), press button 15. Ensure that the button`s backlight is on (lights up continuously).

During the marker beacon zone overflight, the indicator (“O”, “M” or “I”) lights up and the marker audio is heard in the headphones.

If necessary, to mute the marker audio, press button 15 again.

9. To switch the sensitivity of the marker receiver, press button 17. Monitor the sensitivity level by the illumination of the “HI” and “LO” lights.

Note: During the landing approach, the sensitivity of the marker receiver should be set to low (indicated by the “LO” light).

10. To listen to the radio through the cabin speaker, press button 11. To cancel, press the button 11 again.

11. To make an announcement to passengers press buttons 12. Activate the transmission by pressing the “PTT” key on the control wheel.

Note. If the pilot was working on the COM 1 or COM 2 radio station (indicated by the illumination of the “COM 1 MIC” or “COM 2 MIC” button), pressing button 12 will turn on the backlight of this button (“PA”) and turn off the selected radio station button.

12. To isolate the copilot and passengers from external communication and pilot communication, press button 13 “PILOT”. To cancel, press the button again.

To isolate the passengers from external communication and pilot communication, press button 13 “CREW”. To cancel, press the button again.

1.3. Bendix King KMA 26 Audio Control Panel

The Audio Control Panel of the Bendix King KMA 26is equipped with the following controls (refer to Figure 1.12 and Table 1.2).

Figure 1.12 – Bendix king KMA 26 Audio Control Panel

Table 1.2 –Bendix king KMA 26 Purpose of Controls

Form

Name / Purpose

“INTERCOM” Switch:

a) Inner knob: