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Radio communication, known as two-way communication with ATC is required when flying in and out of towered airports and around any controlled airspace. Being a safe pilot, it is always good practice and highly recommended to use radio communication and always report your position and intention at non-towered airports, but not required.

Controlled Airports

The Automated Terminal Information Services (ATIS) is the looped recording that is on a particular frequency that broadcasts the local weather and any other non-controlled information for most airports.

It is updated every hour and it is assigned with an alphabetical letter code. When the new ATIS is recorded a new letter code is assigned. Such as A - Alpha, B - Bravo and so on up to Z - Zulu, then it starts over with A.

At controlled airports (towered), prior to contacting ATC ground control for taxi clearance and instruction, it is required to tune into the ATIS frequency and listen to the entire ATIS. Keep in mind this is not required and the process is different at uncontrolled (non-towered) airports.

All ATIS information ends with the phrase, example: “Advice on initial contact, you have information Whiskey.” 'W' (Whiskey) is the information letter code.

Upon contacting ground control for taxi instruction, it is required you state the ATIS code that was received after you tell the controller your intentions.

Small Note: notice the NOTAM (Notice to Air Mission) in the ATIS at time 1:09.

Video ATIS text - Brown Tower information Whiskey (W), Time 2153Z , Wind 290/07, Visibility 10, Sky clear, Temperature 26, Dewpoint 17, Altimeter 29.96, all instrument and visual approach in use landing and departing runways 26 right and 26 left, caution skydiving in southwest corner of Brown Field below 15 thousand, Notice to Air Mission self-service fuel unavailable only full service at jet center, advise on initial contact you have information Whiskey.

In the video: "Brown ground, Cherokee N5359L. At First Flight, taxi for takeoff, remain in the pattern, information Whiskey." ATC - "Cherokee 5359L taxi to runway 26R via Gulf, Alpha..."


Always listen to the entire ATIS, even if you need to listen to it a couple of times. There are a few things you need to write down for your own information. The first and important one is the information letter code, as stated earlier. The other things you should write down are winds, cloud ceilings/visibility, and altimeter setting.

Listening to the ATIS is also required before contacting Tower prior to entering the airspace of a controlled airport, you are planning to land at.

ATC Services

Radar Traffic Advisories:

ATC facilities that are radar equipped provide assistance to aircraft on either IFR flight plans, along with VFR aircraft that are in radar coverage.

For VFR aircraft ATC can provide safety alerts, traffic advisories, limited vectoring if required, and sequencing at airports that have traffic procedures established.

  • For an example ATC issues a traffic advisory, such as: N123RA “Traffic 10 o’clock 5 miles east bound, Cessna 152, 3,000 feet.”

As the pilot of N123RA, you should note that the aircraft is at your 10 o’clock position, using the noise of your aircraft, like a clock as the 12 o’clock position.

Note: these service provide by ATC is not to relive the pilot of their responsibility to see and avoid.

In addition to radar services, terminal radar service areas (TRSA) have been established at certain terminal airports; for an example Palm Springs (KPSP) airport in Southern California.

These TRSA are depicted on sectional charts and are also listed in the Chart Supplement. The purpose is to provide separation between IFR and VFR aircraft. Whereas Class b and Class C service provides approved IFR and VFR separation.

Lost Communication Procedures:

Losing a radio in flight can happen at any time to anyone. There are a few steps we must know, to enter a towered airport and land safely. If able squawk code 7600 on the transponder (radio failure).

  • Remain outside or above of Class D airspace, until traffic flow has been determined.

  • Enter the traffic pattern and watch for light gun signals from the tower.

  • Acknowledge any ATC transmission or light signal, by ether:

    • Day time​ - rocking the wings.

    • Nighttime - flashing the landing light.


In General Aviation (GA) there are two types of transponders you will see. One is the older dial version and the other is the new fancier digital push button version. Both operate the same way.

These are a part of the airborne surveillance radar system. Transponders are required to be able to fly in controlled airspace. A transponder identifies the aircraft on the controllers radar screen by aircraft type, altitude, and direction.

When ATC request a transponder code, it is called a "squawk." A squawk code is a four-digit code from 0-7 that can be assigned by ATC, there are 4,096 possible codes that can be used.

Button functions:

  • When set to ON – Reports to ATC the 4-digit code selected.

  • When set to STBY (Standby) – It is warming up and not relaying information to ATC.

  • When set to ALT (Altitude) – Reports to ATC the 4-digit squawk code selected and your Pressure Altitude (PA). Transponder and Altimeter do not work together.

  • OFF – Use common sense.

  • IDENT (Identify) – Pressing once will send a pulse that will flash your target on ATC’s radar screen to help locate you.

    • NOTE: Only press when directed to by ATC.

The four basic squawks used are:

  • 1200 – (VFR squawk) this code is used as a default code and should be used when flying VFR, when not assigned a specific code by ATC.

  • 7700 – (Emergency) such as engine failure, all fires, flight control problems, medical emergency.

  • 7600 – (Lost Communications) radio failure and you require light gun signals from the tower, if flying near a towered airport.

  • 7500 – (Hijacking) this code is not used in general aviation flying by yourself. If used there will be military jets escorting you to the nearest airfield.

  • All other squawk codes will be assigned by ATC.

There is one transponder code that civilian aircraft must not use is; 7777, which is used by military interception aircraft.

Mode Types:

There are three types of mode transponders used. The Mode C is the one you will be using:

  • Mode C – Transmits the aircrafts altitude, position and Pressure Altitude automatically to ATC.

  • Mode S – Transmits altitude, position and other data exchange between aircraft and ATC. Normally used in commercial airliners and larger aircraft.

  • Mode A – Only transmits an identifying code.

Where are transponders used?

Here is the short version of what 91.215 says for the locations you must have an operating transponder:

  • It is required for all aircraft in Class A, B and C airspace.

  • Within 30 NM of an airport (Class B airports, Mode C Veil) and from the surface to 10,000 feet MSL.

  • Required in all airspace above and below the ceiling and lateral boundaries of Class B and C airspace up to 10,000 feet MSL.

  • Within all airspace of the lower 48 states and the District of Columbia at and above 10,000 feet MSL. Except for the airspace at 2,500 feet AGL and below.

  • Within 10 NM of an airport from the surface up to 10,000 feet MSL, except below 1,200 feet outside the lateral boundaries of that airport's airspace.


AIM Ch 2 Sec. 1, Ch 4 Sec. 1

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