AIM

4/3/14

4−3−2

Airport Operations

beyond the departure end of the runway and within

300 feet of the traffic pattern altitude.

d.

Many towers are equipped with a tower radar

display. The radar uses are intended to enhance the

effectiveness and efficiency of the local control, or

tower, position. They are not intended to provide

radar services or benefits to pilots except as they may

accrue through a more efficient tower operation. The

four basic uses are:

1. To determine an aircraft’s exact location.

This is accomplished by radar identifying the VFR

aircraft through any of the techniques available to a

radar position, such as having the aircraft squawk
ident

. Once identified, the aircraft’s position and

spatial relationship to other aircraft can be quickly

determined, and standard instructions regarding VFR

operation in Class B, Class C, and Class D surface

areas will be issued. Once initial radar identification

of a VFR aircraft has been established and the

appropriate instructions have been issued, radar

monitoring may be discontinued; the reason being

that the local controller’s primary means of

surveillance in VFR conditions is visually scanning

the airport and local area.

2. To provide radar traffic advisories.

Radar

traffic advisories may be provided to the extent that

the local controller is able to monitor the radar

display. Local control has primary control responsibi-

lities to the aircraft operating on the runways, which

will normally supersede radar monitoring duties.

3. To provide a direction or suggested

heading. 

The local controller may provide pilots

flying VFR with generalized instructions which will

facilitate operations; e.g., “PROCEED SOUTH-

WESTBOUND, ENTER A RIGHT DOWNWIND

RUNWAY THREE ZERO,” or provide a suggested

heading to establish radar identification or as an

advisory aid to navigation; e.g., “SUGGESTED

HEADING TWO TWO ZERO, FOR RADAR

IDENTIFICATION.” In both cases, the instructions

are advisory aids to the pilot flying VFR and are not

radar vectors.

NOTE

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Pilots have complete discretion regarding acceptance of
the suggested headings or directions and have sole
responsibility for seeing and avoiding other aircraft.

4. To provide information and instructions to

aircraft operating within Class B, Class C, and
Class D surface areas.

In an example of this

situation, the local controller would use the radar to

advise a pilot on an extended downwind when to turn

base leg.

NOTE

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The above tower radar applications are intended to
augment the standard functions of the local control
position. There is no controller requirement to maintain
constant radar identification. In fact, such a requirement
could compromise the local controller’s ability to visually
scan the airport and local area to meet FAA responsibilities
to the aircraft operating on the runways and within the
Class B, Class C, and Class D surface areas. Normally,
pilots will not be advised of being in radar contact since
that continued status cannot be guaranteed and since the
purpose of the radar identification is not to establish a link
for the provision of radar services.

e.

A few of the radar equipped towers are

authorized to use the radar to ensure separation

between aircraft in specific situations, while still

others may function as limited radar approach

controls. The various radar uses are strictly a function

of FAA operational need. The facilities may be

indistinguishable to pilots since they are all referred

to as tower and no publication lists the degree of radar

use.  Therefore, when in communication with a
tower controller who may have radar available, do
not assume that constant radar monitoring and
complete ATC radar services are being provided

.

4

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3

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3. Traffic Patterns

At most airports and military air bases, traffic pattern

altitudes for propeller−driven aircraft generally

extend from 600 feet to as high as 1,500 feet above the

ground. Also, traffic pattern altitudes for military

turbojet aircraft sometimes extend up to 2,500 feet

above the ground. Therefore, pilots of en route

aircraft should be constantly on the alert for other

aircraft in traffic patterns and avoid these areas

whenever possible. Traffic pattern altitudes should be

maintained unless otherwise required by the

applicable distance from cloud criteria (14 CFR

Section 91.155). (See FIG 4−3−2 and FIG 4−3−3.)