AIM

4/3/14

4−1−9

Services Available to Pilots

This service is not intended to relieve the pilot of the

responsibility for continual vigilance to see and avoid

other aircraft.

a. Purpose of the Service

1.

The issuance of traffic information as

observed on a radar display is based on the principle

of assisting and advising a pilot that a particular radar

target’s position and track indicates it may intersect or

pass in such proximity to that pilot’s intended flight

path that it warrants attention. This is to alert the pilot

to the traffic, to be on the lookout for it, and thereby

be in a better position to take appropriate action

should the need arise.

2.

Pilots are reminded that the surveillance radar

used by ATC does not provide altitude information

unless the aircraft is equipped with Mode C and the

radar facility is capable of displaying altitude

information.

b. Provisions of the Service

1.

Many factors, such as limitations of the radar,

volume of traffic, controller workload and commu-

nications frequency congestion, could prevent the

controller from providing this service. Controllers

possess complete discretion for determining whether

they are able to provide or continue to provide this

service in a specific case. The controller’s reason

against providing or continuing to provide the service

in a particular case is not subject to question nor need

it be communicated to the pilot. In other words, the

provision of this service is entirely dependent upon

whether controllers believe they are in a position to

provide it. Traffic information is routinely provided

to all aircraft operating on IFR flight plans except

when the pilot declines the service, or the pilot is

operating within Class A airspace. Traffic informa-

tion may be provided to flights not operating on IFR

flight plans when requested by pilots of such flights.

NOTE

−

Radar ATC facilities normally display and monitor both
primary and secondary radar when it is available, except
that secondary radar may be used as the sole display
source in Class A airspace, and under some circumstances
outside of Class A airspace (beyond primary coverage and
in en route areas where only secondary is available).
Secondary radar may also be used outside Class A
airspace as the sole display source when the primary radar
is temporarily unusable or out of service. Pilots in contact
with the affected ATC facility are normally advised when
a temporary outage occurs; i.e., “primary radar out of

service; traffic advisories available on transponder
aircraft only.” This means simply that only the aircraft
which have transponders installed and in use will be
depicted on ATC radar indicators when the primary radar
is temporarily out of service.

2.

When receiving VFR radar advisory service,

pilots should monitor the assigned frequency at all

times. This is to preclude controllers’ concern for

radio failure or emergency assistance to aircraft under

the controller’s jurisdiction. VFR radar advisory

service does not include vectors away from

conflicting traffic unless requested by the pilot. When

advisory service is no longer desired, advise the

controller before changing frequencies and then

change your transponder code to 1200, if applicable.

Pilots should also inform the controller when

changing VFR cruising altitude. Except in programs

where radar service is automatically terminated, the

controller will advise the aircraft when radar is

terminated.

NOTE

−

Participation by VFR pilots in formal programs
implemented at certain terminal locations constitutes pilot
request. This also applies to participating pilots at those
locations where arriving VFR flights are encouraged to
make their first contact with the tower on the approach
control frequency.

c. Issuance of Traffic Information.

Traffic

information will include the following concerning a

target which may constitute traffic for an aircraft that

is:

1. Radar identified

(a)

Azimuth from the aircraft in terms of the

12 hour clock, or

(b)

When rapidly maneuvering civil test or

military aircraft prevent accurate issuance of traffic

as in (a) above, specify the direction from an aircraft’s

position in terms of the eight cardinal compass points

(N, NE, E, SE, S, SW, W, NW). This method must be

terminated at the pilot’s request.

(c)

Distance from the aircraft in nautical

miles;

(d)

Direction in which the target is proceed-

ing; and

(e)

Type of aircraft and altitude if known.

EXAMPLE

−

Traffic 10 o’clock, 3 miles, west-bound (type aircraft and
altitude, if known, of the observed traffic). The altitude may
be known, by means of Mode C, but not verified with the