Radio & Airport Operations | Part 107

The point of this area

A remote pilot listening to CTAF hears an aircraft announce “five miles south, inbound, left downwind runway three-four” and knows, thirty seconds before it appears, roughly where it will be. That is the whole reason this material is on the test.

Listening is not a licence to transmit. Nothing in Part 107 authorises you to broadcast on an aviation frequency, and a radio call from an unfamiliar station on CTAF creates confusion rather than separation. Monitor, build the picture, and stay out of the way.

Radio communications — UA.V.A

Towered and non-towered airports (K1)

At a towered field, ATC sequences and separates traffic, and aircraft do as they are told. At a non-towered field there is no controller — pilots self-announce on a common frequency and separate themselves by agreement and by looking. Traffic at a non-towered field is therefore less predictable, not more, and that is where most of your listening value is.

CTAF (K2)

The Common Traffic Advisory Frequency is the single frequency everyone at a non-towered field uses to announce themselves. It appears on the sectional next to the airport data, marked with a ◎ after the frequency, and in the Chart Supplement. It may be a UNICOM, a MULTICOM (122.9), or the tower frequency when the tower is closed.

Self-announce procedures (K3)

The standard shape is who, where, what, addressed to the airport and repeated at the end:

“Pendleton traffic, Cessna one-two-three-four-alpha, five miles south, inbound for landing runway three-four, Pendleton.”

Calls are made entering the pattern, on downwind, base and final, and when clear of the runway. If you hear an aircraft announce a leg you do not know, look it up before you fly near that field again — the pattern legs are the geometry you are trying to stay out of.

UNICOM (K4) and ATIS (K5)

UNICOM is a non-government advisory station, typically the FBO. It can give an advisory — wind, favoured runway, known traffic — but it is not air traffic control and it clears nobody for anything.
ATIS is a continuous recorded broadcast at busier fields: weather, runway in use, NOTAMs. Each update takes the next letter of the phonetic alphabet, so a pilot saying “with information Kilo” is confirming which broadcast they heard. For a remote pilot it is a free, current weather source at a nearby field.

Call signs and registration (K6)

US civil aircraft carry an N-number. A pilot normally opens with the type and the full number, then may abbreviate to the last three characters once the controller has used the short form first. Airline flights use a company call sign and flight number instead.

The phonetic alphabet (K7)

A Alfa	B Bravo	C Charlie	D Delta	E Echo	F Foxtrot
G Golf	H Hotel	I India	J Juliett	K Kilo	L Lima
M Mike	N November	O Oscar	P Papa	Q Quebec	R Romeo
S Sierra	T Tango	U Uniform	V Victor	W Whiskey	X X-ray
Y Yankee	Z Zulu	Numbers are spoken individually; 9 is “niner”.

Phraseology — altitude, direction, speed, time (K8)

Altitude — spoken in thousands and hundreds: 4,500 is “four thousand five hundred”.
Direction — three digits, magnetic: heading 090 is “zero niner zero”.
Speed — knots, spoken digit by digit.
Time — UTC (Zulu) in aviation. The minutes alone are used when the hour is not in doubt.

Airport operations — UA.V.B

Types of airport (K1) and towers (K2)

Towered, non-towered, heliport and seaplane base are all airports for the purpose of § 107.43, which prohibits interfering with operations and traffic patterns at any of them. A heliport with no runway, no tower and no published pattern is still protected, and helicopters arrive from directions a runway would never suggest.

Runway markings and signage (K3)

Runways are numbered by their magnetic heading to the nearest ten degrees, with the last digit dropped — runway 34 points about 340°. The opposite end is 180° different, so 34 and 16 are the same strip of pavement. Parallel runways add L, C and R.

Signs: red with white text is mandatory (a hold short); yellow with black text is a direction or location. You will not be on the surface, but the numbers tell you which way traffic is flowing.

Traffic patterns (K4)

The standard pattern is left-hand, flown at roughly 1,000 ft AGL for light aircraft: upwind, crosswind, downwind, base, final. Right-hand patterns exist where terrain or noise requires it, and are marked RP in the Chart Supplement.

What this means at 400 ft: an aircraft on final is descending through your altitude, and it is doing so on a predictable line extending a mile or more from the runway end. That extended centreline is the piece of sky to stay out of.

SIDA (K5)

A Security Identification Display Area is a secured part of a commercial airport where badges are required and access is controlled. It is a ground security area, not an airspace class — but launching from inside one is a security matter regardless of the airspace above it.

Sources of airport data (K6)

Aeronautical charts (K6a) — the sectional gives airport symbol, elevation, runway length, CTAF and lighting at a glance.
Chart Supplement (K6b) — the former Airport/Facility Directory. Everything the chart has no room for: full runway data, frequencies, services, remarks, right-hand patterns, and noise procedures.

Wildlife hazards (K7)

Birds are a genuine threat to a small unmanned aircraft, and raptors in particular will attack a multirotor as a territorial rival. Land if you are being followed rather than trying to outfly it. Report a wildlife strike through the FAA Wildlife Strike Database.

Airport and seaplane base lighting (K8)

The rotating beacon tells you what kind of field it is, at night and from a distance:

White–green — lighted civil land airport.
White–yellow — lighted seaplane base.
Green–yellow–white — heliport.
Two quick white flashes with green — military.

A beacon operating in daylight at a towered field is a conventional signal that the ground visibility is below 3 SM or the ceiling below 1,000 ft — useful information, and weather you cannot legally fly in either.