Aeronautical Information Manual (AIM), page 218

Index   217 -- Page 218 -- 219


are limited to communications between the tower and
aircraft on the ground and between the tower and
utility vehicles on the airport, provide a clear VHF
channel for arriving and departing aircraft. They are
used for issuance of taxi information, clearances, and

other necessary contacts between the tower and

aircraft or other vehicles operated on the airport. A

pilot who has just landed should not change from the

tower frequency to the ground control frequency until
directed to do so by the controller. Normally, only one
ground control frequency is assigned at an airport;
however, at locations where the amount of traffic so
warrants, a second ground control frequency and/or
another frequency designated as a clearance delivery
frequency, may be assigned.
d. A controller may omit the ground or local
control frequency if the controller believes the pilot
knows which frequency is in use. If the ground
control frequency is in the 121 MHz bandwidth the
controller may omit the numbers preceding the
decimal point; e.g., 121.7, "CONTACT GROUND
POINT SEVEN." However, if any doubt exists as to
what frequency is in use, the pilot should promptly
request the controller to provide that information.

e. Controllers will normally avoid issuing a radio
frequency change to helicopters, known to be
single-piloted, which are hovering, air taxiing, or
flying near the ground. At times, it may be necessary
for pilots to alert ATC regarding single pilot
operations to minimize delay of essential ATC
communications. Whenever possible, ATC instruc-
tions will be relayed through the frequency being
monitored until a frequency change can be
accomplished. You must promptly advise ATC if you
are unable to comply with a frequency change. Also,
you should advise ATC if you must land to
accomplish the frequency change unless it is clear the
landing will have no impact on other air traffic;
e.g., on a taxiway or in a helicopter operating area.

4-3-15. Gate Holding Due to Departure

a. Pilots should contact ground control or
clearance delivery prior to starting engines as gate
hold procedures will be in effect whenever departure
delays exceed or are anticipated to exceed
15 minutes. The sequence for departure will be
maintained in accordance with initial call up unless

modified by flow control restrictions. Pilots should
monitor the ground control or clearance delivery
frequency for engine startup advisories or new
proposed start time if the delay changes.

b. The tower controller will consider that pilots of

turbine-powered aircraft are ready for takeoff when

they reach the runway or warm-up block unless

advised otherwise.

4-3-16. VFR Flights in Terminal Areas
Use reasonable restraint in exercising the prerogative
of VFR flight, especially in terminal areas. The
weather minimums and distances from clouds are
minimums. Giving yourself a greater margin in
specific instances is just good judgment.
a. Approach Area. Conducting a VFR operation
in a Class B, Class C, Class D, and Class E surface
area when the official visibility is 3 or 4 miles is not
prohibited, but good judgment would dictate that you
keep out of the approach area.

b. Reduced Visibility. It has always been recog-
nized that precipitation reduces forward visibility.
Consequently, although again it may be perfectly
legal to cancel your IFR flight plan at any time you
can proceed VFR, it is good practice, when
precipitation is occurring, to continue IFR operation
into a terminal area until you are reasonably close to
your destination.
c. Simulated Instrument Flights. In conducting
simulated instrument flights, be sure that the weather
is good enough to compensate for the restricted
visibility of the safety pilot and your greater
concentration on your flight instruments. Give
yourself a little greater margin when your flight plan
lies in or near a busy airway or close to an airport.

4-3-17. VFR Helicopter Operations at
Controlled Airports
a. General.

1. The following ATC procedures and phrase-
ologies recognize the unique capabilities of
helicopters and were developed to improve service to
all users. Helicopter design characteristics and user
needs often require operations from movement areas
and nonmovement areas within the airport boundary.
In order for ATC to properly apply these procedures,
it is essential that pilots familiarize themselves with

4-3-18 Airport Operations

Page 218 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures

Index   217 -- Page 218 -- 219