Radio Communication

Flying is greatly facilitated by the ability of the pilot to communicate with ground facilities and other aircraft. In the Navigation chapter, the term “NAV/COM” was used. This chapter will deal with the “COM” part of the radio.

Communication with the following facilities enhances safety, and in many cases is required; These are:

• 1. ATC
  • - Ground Control for taxi instructions
  • - Tower for takeoff and landing instructions
  • - Approach and Departure Radar
  • - ATC enroute Centers for clearances, radar surveillance, and traffic separation
• 2. FSS - Contact with Flight Service Stations for weather information and Flight Plans .
• 3. FBO - Contact Fixed Based Operators for fuel, airport advisories and service.
• 4. AIRCRAFT- Aircraft to aircraft communications. Announce takeoff and landing intentions.

Frequencies

The communication band for civilian aircraft operate in the range of 118.00 MHz to 135.975mhz.

Many transceivers can be tuned to only 360 frequencies( called 360 channels). The frequencies that can be selected are 118.00 to 135.95. Channels exist every 0.05 MHz. Later models are capable of 720 channel operation. They allow a 0 or 5 to be selected for the 6th digit by use of a toggle switch. In one position the 6th digit is zero; in the other position, it is 5. However, to date, virtually all FAA frequencies operate on the 360 channel frequencies.

Phraseology

Good phraseology and standard communication techniques enhance pilot-controller understanding. Jargon, “CB” slang, and vulgarities have no place in aviation communication. When initially identifying your aircraft “N” number, you should use the Phonetic Alphabet. Examples: 1256 X-Ray (1256X), 753 Alpha Lima (753AL), etc. Thereafter, following the initial call-up, controller and pilot will use only the last 3 numbers/letters. Example, 56 X-Ray, or 3 Alpha Lima.

The phonetic alphabet can also be used to spell out words or phrases when communication is difficult to understand. As shown in the table below, a Morse code is also associated with each letter and number. These codes will be heard over NDB and VOR stations as station identifiers.

Pronunciation of Figures

Figures indicating hundreds and thousands are pronounced as follows:

• 500 is FIVE HUNDRED
• 5,000 is FIVE THOUSAND
• 4,500 is FOUR THOUSAND FIVE HUNDRED
• 10,000 is ONE ZERO THOUSAND
• 12,600 is ONE TWO THOUSAND SIX HUNDRED

Victor airway numbers such as V12 are pronounced as “VICTOR TWELVE”.

When reciting other number combinations pronounce each digit. For 10, say “ONE ZERO”.

Altitudes are pronounced as ONE ZERO THOUSAND FIVE HUNDRED. Altitudes at and above 18,000 feet are called FLIGHT LEVELS, such as FL180, ( Flight level One Eight Zero), FL230 (Flight Level Two Three Zero), FL 390, etc.

Magnetic Headings are pronounced as:

• Magnetic Course 005° pronounced as “Zero Zero Five”
• True Course 050° as “Zero Five Zero True”
• Magnetic Bearing 256° as “Two Five Six”
• Magnetic Heading 125° as “One Two Five”
• Wind Direction and Velocity 220° at 35kt as “Two Two Zero at Three Five”

Note: Wind direction is given by ATC (Towers etc.) in Magnetic Direction. Wind given in Weather reports, forecasts, etc. is True Direction.

Speeds such as 125 kts. are pronounced as One Two Five Knots”. In communications where speed is implicit, such as a controller instruction to increase speed to 150 kts., the controller may omit the word “Knots”; i.e. may use the term “increase speed to 150”.

Coordinated Universal Time (UTC)

In aviation terminology, time is related to the time at the Zero Meridian, which runs North/South through Greenwich, England. It was formerly called Greenwich Mean Time (GMT). The current terminology is Coordinated Universal Time (abbreviated UTC). When speaking time, pilots and FAA personnel refer to UTC time as ZULU time. The time 1345Z would be pronounces as “One Three Four Five Zulu”.

Examples:

• 0000 is pronounced Zero Zero Zero Zero ( midnight)
• 0925 is pronounced Zero Niner Two Five (9:25 a.m.)
• 1830 is pronounced One Eight Three Zero (6:30 p.m.)

Initial Call-Up Terminology

At your initial call-up, you generally use the following format:

• Who you are calling
• Who are you
• Where are you
• ·What you want to do or are doing.

Examples :
1. "New York Approach, Bonanza One Two Three Four Romeo, Over"

When calling Approach Control, or other ATC facilities, monitor how busy the controller is. If calling at an active time, simply state the ATC name, your identification, ending with the word OVER. This term means you are requesting the called party to respond.If the controller does not appear busy, and your message is short, you can state the entire message on initial call-up You could have also given your position and altitude. This shortens the total conversation time by initially providing the controller more information. Judgement is required here. If the controller cannot respond to your call immediately, their response will be “aircraft calling New York, stand by” or with “Bonanza One Two Three Four Romeo, stand by”.

Note that the controller does NOT say OVER, as no communication by the pilot is required until requested by the controller. The controller has recognized you and will come back as soon as possible.

You are announcing to other aircraft in the area where you are, and what you are doing. You do NOT end with the term OVER, as you are not requesting a response.

You use the term OUT to indicate the communication is ended, and no further response is expected.

Uncontrolled Airports

At airports without a control tower, it is very important to be alert for other aircraft which may be operating in close proximity to the airport. Other aircraft close to you may not have radio equipment. All radio equipped aircraft operating around an uncontrolled airport should communicate on a Common Frequency.

Common Traffic Advisory Freqiency (CTAF)

Most uncontrolled airports are equipped with a ground station for communication with ground personnel and air to air communication between aircraft operating in the vicinity. This frequency is published within the airport information block on the aeronautical chart. It is called the Common Traffic Advisory Frequency (CTAF) and is denoted by the letter C within either a Magenta or Blue filled circle following the frequency number.

The frequencies will normally be in the range of 122.7 to 122.95. Occasionally, due to a high volume of communication traffic within a geographical area, frequencies above 123.0 MHz may be used. When approaching such airports, call about ten miles out, requesting airport advisory. Normally ground personnel will respond with information about traffic, active runway and wind. It is important to note that such information is advisory in nature. The pilot is the final authority for operation of the aircraft.

INBOUND

• Entry into downwind Leg
• Turn to Base Leg
• Turn to Final Leg
• Clear of the active runway

OUTBOUND

• On the ramp, ready to taxi to departure runway
• Ready for departure, runway to be used , and direction of departure
  

Ground based stations at uncontrolled airports.

• LLA - Local Airport Advisory - used at airports where a FSS is located. Call the FSS on 123.6 and request airport advisory. Example: “Hickory Radio, Skyhawk 3270 is 10 miles East, at Three Thousand five hundred, landing Hickory. Request airport advisory”. The FSS will respond with Wind direction and Velocity, Altimeter setting, active runway, and any known traffic.

• UNICOM - these are non-government stations operated by the local operator or airport management, to advise about known traffic, which runway is being used, and may advise wind condition. They transmit on 122.7, 122.725, 1228, 122.975 and 123.0

• MULTICOM - frequency 122.9 MHz. Pilots should use this frequency at airports where there is no ground-based communication facility such as UNICOM or LAA. The pilot is to self-announce position and intentions the same as on UNICOM. This procedure allows other aircraft in the area to know where you are and your intentions. The MULTICOM frequency of 122.9 is shown on the charts the same as LAA and UNICOM, with the circled C indicator following the frequency.

Controlled Airports

Communication at control towered airports involve communication with at least 3 facilities.

• Automatic Terminal Information Service (ATIS) (Listen only)
• Ground Control
• Tower

Additionally, at larger airports, there will be:

• Clearance Delivery
• Approach Control
• Departure Control

ATIS

ATIS broadcasts a repetitive tape containing information such as runways in use, altimeter setting, weather conditions, wind direction and velocity, communication frequencies and other information pertinent to operating in the vicinity of or on the airport. Prior to departure, you should listen to ATIS before to calling Clearance Delivery or Ground Control. On arrival, listen to ATIS before calling Approach Control.

Whenever the weather or other conditions change during the day, the recording is updated. Each time a new recording is made, it is assigned an identifier name, starting with ALPHA. Subsequent updates are identified as BRAVO, CHARLIE, etc. When making initial contact with approach Control or Tower on arrival, and Clearance Delivery or Ground Control on departure you should state that you have the ATIS information. Use its identifier name; i.e. CHARLIE.

EXAMPLES:

• “Raleigh Clearance Delivery, Bonanza 123 Yankee Foxtrot, ready to depart VFR to the WEST, with information BRAVO. Request clearance.”
• “Greensboro Approach, Cherokee 6835 Juliet, Two Zero East, Three Thousand, inbound Greensboro, with information GOLF”.
  

Clearance Delivery

At larger airports which have a high volume of operations, Clearance Delivery provides initial departure information to the pilot. This frees Ground Control to concentrate directing traffic on the ramps and taxiways. Clearance Delivery coordinates information with Departure Control by assigning a transponder code prior to becoming airborne. This saves time both for the Ground Controller and the Departure Controller. It allows the pilot to set-up the transponder and departure frequencies prior to dparture, as well as giving the pilot advance information on departure procedures.

The Clearance Delivery Frequency is listed in the Airport/Facility Directory and is included in the ATIS information. In your call-up, state your aircraft type and identification, VFR or IFR, departure direction or destination, and planned altitude.

Two Four Seven Four X-Ray, you are cleared to depart runway 27 Right VFR westbound. Squawk One Three Five Two. Departure Control frequency is One Two Six Point Seven Five. Contact Ground Control on One Two One Point Niner prior to taxi.

Ground Control

Ground Control is responsible for the flow of aircraft taxiing on the ramps and taxiways. On your call up, identify your aircraft type and number, your location on the airport, with request to taxi. If no Clearance Delivery is at the airport, include the ATIS Identifier. Ground control frequencies can be found on the front panel of the Aeronautical Chart and the Airport/Facility Directory.

"Beech Five Two Six Four Two taxi straight ahead to taxiway Alpha, turn left and taxi to One Eight Right. Contact tower on One Two Seven Point Five Five when ready"

You should read back the controllers instructions, in particular any HOLD SHORT instructions. You are under the supervision of Ground Control during your taxi and run-up. When you are ready to depart, you then switch to the tower frequency. Ground and tower controllers are in the same room in the tower, and coordinate the hand-off of traffic to each other.

Tower Control

The tower controls operations on the runways and in the airspace around the airport. After you have completed all pre-flight actions, call the tower on their frequency with the following information.

Address the Tower. “Stewart Tower"
Who you are: “Skyhawk Five Six Two Three ALFA “
Your intention: “Ready for takeoff runway TWO SEVEN”.

The tower will subsequently clear you for takeoff.
1. It may be in the form :
TwoThree Alpha, taxi into position and hold.
You respond:
Roger, Position and Hold. You taxi onto the runway, but do not take off.

OR

You may respond with “Roger”, or may simply depart. You should monitor the tower frequency until told by the tower to contact Departure Control or until tower ends the communication.

Departure Control

Departure Control is a Radar Service at Class B and C airports. To operate in this environment, you must be equipped with a Mode C (altitude reporting) transponder. The Departure Controller will assign altitudes and headings as required to provide traffic separation. If the controller’s instructions place you into a position to violate VFR rules (such as clearance from clouds) , you should inform the controller to get an amended clearance.

The word “OUT” terminates the communication. However, often controllers and pilots will use “good day” as a more congenial ending.

Approach Control

Approach Control is a radar service similar to Departure Control. Contact with Approach Control is mandatory prior to entry into Class B and C airspace. On initial call-up, identify type and number of aircraft, position, altitude and destination. The controller will respond with a “SQUAWK” code for the transponder.

"Daytona Approach, Cherokee Three Two Two Three ROMEO, Saint Augustine VOR, Three Thousand Five Hundred, inbound Daytona."

"Cherokee Three Two Two Three ROMEO, this is Daytona Approach. Squawk Two Three One Five and Ident."

You acknowledge the instruction. The radar controller will continue to track your “blip” on the radar screen, give traffic advisories as necessary, and may vector you into the downwind leg in the pattern. The controller will then hand you off to the tower controller for landing instructions.

If you are flying through Class C airspace without landing, tell the controller the planned route of flight and altitude you wish to maintain. Radar Flight Following will be granted outside the class B or C airspace on a “workload permitting” basis upon pilot request. The radar surveillance usually can be provided up to 20 or 30 miles from the radar site.

Transponder Operation

There have been a number of modes of transponder operation during it’s history. The mode now required for operation in Class B and C airspace is Mode C. This mode couples an encoder in the altimeter which reports the altitude in hundreds of feet. The Transponder also has 4 digital dials, each with numbers 0 through 7. Therefore, number combinations from 0000 to 7777 can be dialed in. This is called the “SQUAWK code. The numbers 7500, 7600 , 7700, and 7777 are reserved for special use:

• 7700 - emergency
• 7600 - lost radio communications
• 7500 - code for hijacking
• 7777 - used by military

The transponder operates by receiving an interrogation signal from the radar station. It in turn returns certain coded information back to the radar when the transponder is set for normal operation. The SQUAWK code and the altitude in hundreds of feet are returned to the radar. The controllers radar scope shows a “blip” on the radar screen along with the SQUAWK code and altitude.

A Mode C altitude reporting transponder is required:

• When flying at or above 10,000 feet
• When flying within Class B Mode C veil (30 Nm around a Class B airport). (Note: there are exceptions for operations into smaller airports which lie within the 30 Nm veil).
• When flying in or above Class C airspace
• When crossing the U.S Air Defence Identification Zone (ADIZ).
  

The unit is equipped with a rotary switch with several positions.

• OFF - turns the transponder off
• STY - (Standby) - turns the transponder for warm-up. The transponder does NOT respond to the radar interrogation signals.
• ON - Turns the transponder on and allows it to respond in Mode A (No altitude reporting). This shown a blip on the radar screen but NO ALTITUDE DATA.
• ALT - Allows a reply in either Mode A ( no altitude report) or Mode C (altitude report) as requested by the radar interrogating signal.

A button, called the IDENT BUTTON, when depressed sends a special identifying signal to the radar. The IDENT should only be sent when requested by the controller.

Controllers may use the following terminology when referring to transponder operation

• SQUAWK (number) - set the 4 digit code into the transponder. Example: Squawk 4316.
• IDENT - depress the IDENT Button
• Squawk (number) and IDENT - set code into the transponder dials, then IDENT.
• SQUAWK STANDBY - Switch function switch to STY
• SQUAWK ALTITUDE - Switch to ALT position
• STOP ALTITUDE SQUAWK - Switch from ALT to ON
• SQUAWK MAYDAY - select code 7700
• STOP SQUAWK - turn transponder off
• SQUAWK VFR - select code 1200 when operating without ATC contact. 1200 is known as the VFR squawk code.
  

Radar Assistance to Lost Aircraft

Never hesitate to contact radar services when in serious doubt of your location, are encountering poor weather, or are in need of other assistance. When flying cross untry, it is good practice to keep track of, or know where to find, the various approach control services available along your route. This should be a part of your flight planning. Even the Air Traffic Control Centers (ARTC) which normally handle enroute IFR flight will render assistance to lost aircraft.

If radar frequencies are not readily available, contact the nearest Tower or FSS, and provide then with the best location data you can. They will coordinate with, or refer you to the nearest radar facility. Usually an emergency situation can be avoided by requesting assistance as soon as you are not sure of your position.

ATC can give you radar vectors to your destination or suitable alternate airport.

Emergency Locator Transmitter (ELT)

Emergency locator Transmitters have been developed to transmit a locating signal in the event of significant impact. They are battery powered, and self contained. When activated by impact, they transmit a homing signal on 121.5 and 243.9 Mhz. This signal provides homing for search and rescue equipment.

The power source must be capable of sustaining the signal for 48 hours.

The ELT is equipped with a gravity activated switch, which automatically activated the ELT upon significant impact.

They generally have 3 switch positions:

• ON - causes a continuous broadcast of the signal on 121.5 and 243.0 MHz. This position is used for test purposes.
• OFF - no broadcast is possible
• ARMED - means the gravity switch can be activated in the event of sufficient impact.
  

Aerobatics, or hard landing have been known to set off an ELT. A good check for a false ELT signal is to turn a radio receiver to 121.5 MHz prior to engine shut-down. If the ELT has been triggered, you will hear a steady signal on this frequency. Corrective action should be taken.

ELT’s should be tested in accordance to manufacturers instructions. Testing should preferably be done in a shielded room. Tests should be conducted only during the first 5 minutes after the hour. If a test is to be made at any other time, it should be coordinated with the Control Tower or FSS.

ELT batteries must be replaced or recharged:

• If the battery has been used more than one hour cumulative.
• When 50% of the useful life of the battery has expired.