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AIM

10/12/17

4−1−10

Services Available to Pilots

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

pilot for accuracy. (To be valid for separation purposes by

ATC, the accuracy of Mode C readouts must be verified.

This is usually accomplished upon initial entry into the

radar system by a comparison of the readout to pilot stated

altitude, or the field elevation in the case of continuous

readout being received from an aircraft on the airport.)

When necessary to issue traffic advisories containing

unverified altitude information, the controller will issue the

indicated altitude of the aircraft. The pilot may upon

receipt of traffic information, request a vector (heading) to

avoid such traffic. The vector will be provided to the extent

possible as determined by the controller provided the

aircraft to be vectored is within the airspace under the

jurisdiction of the controller.

2. Not radar identified

(a) Distance and direction with respect to a

fix;

(b) Direction in which the target is proceed-

ing; and

(c) Type of aircraft and altitude if known.

EXAMPLE−

Traffic 8 miles south of the airport northeastbound, (type

aircraft and altitude if known).

d. The examples depicted in the following figures

point out the possible error in the position of this

traffic when it is necessary for a pilot to apply drift

correction to maintain this track. This error could also

occur in the event a change in course is made at the

time radar traffic information is issued.

FIG 4−1−1

Induced Error in Position of Traffic

TRACK

(A)

(B)

WIND

TRACK

EXAMPLE−

In FIG 4−1−1 traffic information would be issued to the

pilot of aircraft “A” as 12 o’clock. The actual position of

the traffic as seen by the pilot of aircraft “A” would be

2 o’clock. Traffic information issued to aircraft “B” would

also be given as 12 o’clock, but in this case, the pilot of “B”

would see the traffic at 10 o’clock.

FIG 4−1−2

Induced Error in Position of Traffic

TRACK

(C)

(D)

WIND

TRACK

EXAMPLE−

In FIG 4−1−2 traffic information would be issued to the

pilot of aircraft “C” as 2 o’clock. The actual position of the

traffic as seen by the pilot of aircraft “C” would be

3 o’clock. Traffic information issued to aircraft “D” would

be at an 11 o’clock position. Since it is not necessary for the

pilot of aircraft “D” to apply wind correction (crab) to

remain on track, the actual position of the traffic issued

would be correct. Since the radar controller can only

observe aircraft track (course) on the radar display, traffic

advisories are issued accordingly, and pilots should give

due consideration to this fact when looking for reported

traffic.

4−1−16. Safety Alert
A safety alert will be issued to pilots of aircraft being

controlled by ATC if the controller is aware the

aircraft is at an altitude which, in the controller’s

judgment, places the aircraft in unsafe proximity to

terrain, obstructions or other aircraft. The provision

of this service is contingent upon the capability of the

controller to have an awareness of a situation

involving unsafe proximity to terrain, obstructions

and uncontrolled aircraft. The issuance of a safety

alert cannot be mandated, but it can be expected on a

3/15/07

7110.65R CHG 2

AIM

9/13/18