The FAA uses Coordinated Universal Time (UTC)—
also known as Greenwich Mean Time (GMT) or Zulu
Time (Z)—for all operations.
The 24-hour clock system is used in radiotelephone
transmissions. The first two figures and the minutes
indicate the hour by the last two figures.
Examples: 0000: ZERO ZERO ZERO ZERO (12 o’clock
0920: ZERO NINER TWO ZERO (9:20 a.m.)
Figures indicating hundreds and thousands in round
numbers, as for ceiling heights and upper wind levels
up to 9,900 are spoken in accordance with the
500: FIVE HUNDRED
4500: FOUR THOUSAND FIVE HUNDRED
(Not forty-five hundred)
Numbers above 9,900 are spoken by separating the
digits preceding the word “thousand” as follows:
10000: ONE ZERO THOUSAND (10,000)
13500: ONE THREE THOUSAND FIVE
Altitudes up to but not including 18,000 feet MSL
are spoken by stating the separate digits of the
thousands, plus the hundreds, if appropriate, and
rounded. They are always MSL.
450: FOUR HUNDRED FIFTY
1,200: ONE THOUSAND TWO HUNDRED
(Not twelve hundred)
12,500: ONE TWO THOUSAND FIVE
HUNDRED (Not twelve thousand five hundred)
Pilots should use the correct phonetic alphabet when
identifying their aircraft during initial contact with ATC
facilities. Additionally, use the phonetic equivalents for
single letters and to spell out groups of letters or difficult
words during difficult communications conditions.
A good way to learn radio language is to visit a tower,
or sit in the parking lot with a receiver, and listen to
Uses of a VHF Radio
There is confusion among pilots as to which frequencies
may be used from air-to-ground, balloon-to-chase
crew, for instance. Many balloonists use 123.3 and
123.5 for air-to-ground (pilot-to-chase crew), as these
frequencies are for glider schools and not many soaring
planes are in the air at sunrise. Since all users of the
airwaves must have an ID or call, ground crews identify
themselves by adding chase to the aircraft call sign.
For example, the chase call for “Balloon 12345”
would be “12345 Chase.”
Air-to-air is 122.75. Remember that everyone in the
air is using this frequency, so keep your transmissions
brief. A balloon pilot trying to contact a circling
airplane would try 122.75 first. Weather information
is available on VHF radio. A balloon pilot could obtain
nearby weather reports by tuning to the ATIS. [Refer
to appendix A] The appropriate frequency is listed
on the cover of the sectional chart, and in the airport
information block printed on the chart near the
Another source of weather information is the AWOS.
AWOS frequencies may be found in the Airport/
Facility Directory published by the National Ocean
Service (NOAA) and available at the local pilots
supply store or by subscription.
If you want to actually speak with a weather briefer,
you can call the nearest AFSS on any of several
frequencies. Flight Watch, the en route flight advisory
service that provides timely weather information upon
pilot request, can be reached on 122.0.