AIRBORNE RADIO EQUIPMENT

                                                    Airborne Radio Equipment 

 

1.   Introduction 

       Dan Air Flight 1008 departed from Manchester, England to Tenerife, one of Spain’s Canary Islands on the morning of April 25, 1980. Upon reaching the airport, the plane was instructed by the control tower to take an unpublished, not officially approved, and potentially dangerous holding pattern above Los Rodeos Airport. But the pilot seemed to have mistaken the word “inbound” for “outbound” in the instructions he received, flying in the opposite direction to which he was supposed to. This disaster was caused by a single misheard word made by the Boeing 727’s flight crew. Every year, several accidents are caused by poor communication and many are averted by the usage of onboard radio equipment. Proper communication is the backbone of a safe flying experience. By staying in constant communication with ATC and other pilots, it's possible to improve one's situational awareness. There are certain aids provided in each aircraft to supplement the safety of aircraft and souls on board. First there used to be hand signals at the start, then smoke signals, and then came the radios. 

 2.  Communication :

      It is used to be that a wing wave or rapid tail deflection was all that was needed by the pilot of an aircraft to acknowledge a visual cue from a person on the ground.

3.  Types of Communication Breakdown: 

     Communication breakdown may result from failure to hear or to respond to a message because of: 

(a) Communication equipment problems caused by a malfunction or complete failure of aircraft or ground equipment (becoming less of an issue with improved system redundancy). (b) Radio Interference, which makes the message difficult or impossible to interpret. 

(c) Blocked Transmissions / Undetected Simultaneous Transmissions

(d) Call-sign Confusion - the message was wrongly addressed or was misunderstood by another aircraft 

(e) Aircrew unintended mismanagement of radio frequency or selection, which remains one of the main causes of prolonged loss of communication. 

(f) A breakdown in radio discipline resulting in the pilot receiving and acting on an incorrect version of the message passed, due for example to: 

 Failure to use standard phraseology.

 Poor language skills. 

4. Causes of Communication Breakdown:

 

        Communication breakdown may result in, the pilot failing to fly the required vertical profile which may lead to a level bust, or not following the required horizontal profile which may result in the following consequences: 

(a) Either situation may cause the aircraft to make an unauthorized entry of designated airspace (airspace violation) which may lead to disruption of air traffic causing risk to other airspace users and increased workload for pilots and controllers or may put the infringing aircraft at risk from ground hazards such as artillery firing.

(b) Either situation can lead to loss of separation from other aircraft or airborne objects (Balloons or parachutists for example) which may result in a collision. 

(c) Level bust may also lead to a collision with an obstacle or the ground (Controlled Flight into Terrain). 

(d) The pilot changing to an incorrect frequency or not implementing a frequency change, leading to: 

 i. Loss of Situational Awareness. 

 ii. This is exacerbated if the pilot fails to check in on any frequency having acknowledged a requested change 

(e) Runway Incursion and other hazardous situations while on the ground. 

Bestower Factors: 

 The bestower factors for the communication breakdown are as follows: 

 (a) Pilot / ATCO workload 

(b) Inadequate language proficiency 

(c) Frequency Congestion 

(d) Non-standard phraseology 

(e) Radio Interference

(f) Distractions or interruptions 

(g) Fatigue 

(h) Emergency Communications Remedial measures 

 5.    Improved pilot and ATCO :

             Improved pilot and ATCO training to ensure that pilots and ATCOs understand and follow SOPs, particularly concerning: 

 (a) Radio Discipline. 

 (b) Prevention of blocked transmissions. 

 (c) Emergency communications. 

 (d) Recognize and understand working environments and constraints. 

 (e) Listen to other communications on the frequency to build situational awareness, avoid talking over transmissions by other users, and be alert to potential call sign confusion. 

6. Equipment designed:

         Equipment designed to warn of a potential collision with the ground, Minimum Safe Altitude Warning (MSAW), or airspace infringement Area Proximity Warning (APW).

7. Hertzian waves:

        Hertzian Waves are a type of electromagnetic radiation. They can have wavelengths that are very long compared to different types of electromagnetic waves like infrared or gamma. They are the longest type of electromagnetic wave and travel at the speed of light.

Founders of Radio/ Hertzian Waves:

8.      James Clerk Maxwell, the founder of radio waves said that electromagnetic waves are combined from the vibrating magnetic field and electric field.

9.      David E. Hughes was the first to transmit and receive radio waves when he found disruption in a homemade phone

10.     Heinrich Rudolf Hertz, produced and measured the radio waves in the laboratory, supplementing the idea of Maxwell and David Edward Hughes.

11.     Edward Howard Armstrong was an electrical engineer. He discovered the frequency modulation

Basic working principle:

12.        Radio wave is formed when an electricity object from the carrier wave has the combination of an electric field and magnetic field that vibrated and propagated through space and brings the energy (electromagnetic radiation) and the electricity object modulated with the audio wave in the frequency radio wave at the spectrum electromagnetic.

Energy is alternately stored in this field and returned to the conductor for typical transformer operation. As the frequency of current alternation increases, lesser energy stored in the field returns to the conductor and instead radiated into space in form of EM waves.

13.         For Radios, the above-mentioned phenomenon is exploited for the transmission of signals, and the conductor employed to radiate in this manner is called a transmitting antenna. Now if these radiated EM waves pass through a conductor, they transmit some energy into the conductor by setting the conductor’s electron into motion. As and when the EM field varies, the pattern of electron flow changes which in turn varies the current generated Hence by causing a variation in the EM field via radiating antenna, we can bring about a similar variation in the receiving antenna. This is the basic theory of radio transmission.

14.      All Radio waves have the same basic structure with wavelength and amplitude being the only things that change if and when a radio wave is modulated in some way, this could be with sound or other data. Radio transmission is an electromagnetic wave with the same characteristics as light or heat.

(a) Wavelength is the linear measurement of the wave.

(b) Cycle is the interval in which the wave rises and falls between its crest and trough.

(c) Frequency is the number of cycles/second.

(d) Amplitude is the strength of the signal. Amplitude decreases with distance.

15.         The radio wave diagram below shows an UN-modulated radio wave structure. All unmodulated waves look very much the same.

The Transmission Of Programs Or Information by Radio:

16. The telecast Frequencies are being used in various fields, amongst them include:

(a) FM Radio Broadcast

(b) Television Broadcast

(c) Land Mobile Stations (Emergency, Business, and Military)

(d) Amateur Radio

(e) Marine Communications

(f) Aircraft Communications

(g) Air Traffic Control

(h) Air Navigation Systems (e.g. VOR/DME, NDB)

 This scale, is divided into frequency bands:

Abbreviation:                   Frequency:                             Band Wave Length:

VLF                               3-30 kHz                      100-10 KM     

 LF                                       30-300 kHz                        10-1 KM

 MF                                   300-3,000kHz              1KM-100 M    

 HF                                      3-30 MHz 100                  M-10 M

VHF                                     30-300 MHz                      10 M-1 M

UHF                                    300-3,000 MHz                100 CM-10 CM

SHF                                     3-30 GHz 10                       CM-1 CM

EHF                                     More than 30 GHz          Less Than 1 CM

• 190 - 1750 kHz                                   Non-Directional Radio Beacon

• 108.0 - 111.975  MHz                      ILS Localizer

• 108.0 - 117.975 MHz                       VOR

• 328.6 - 335.4 MHz                          ILS Glide Slope.

• 960.0 - 1215.0 MHz                         DME and TACAN.

• 1563.42 - 1587.42 MHz                               GPS