AIM

4/20/23

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4

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13

ATC Clearances and Aircraft Separation

g. Scanning Techniques for Traffic Avoidance.

1.

Pilots must be aware of the limitations inherent in the visual scanning process. These limitations may

include:

(a)

Reduced scan frequency due to concentration on flight instruments or tablets and distraction with

passengers.

(b)

Blind spots related to high

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wing and low

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wing aircraft in addition to windshield posts and sun visors.

(c)

Prevailing weather conditions including reduced visibility and the position of the sun.

(d)

The attitude of the aircraft will create additional blind spots.

(e)

The physical limitations of the human eye, including the time required to (re)focus on near and far

objects, from the instruments to the horizon for example; empty field myopia, narrow field of vision and
atmospheric lighting all affect our ability to detect another aircraft.

2.

Best practices to see and avoid:

(a)

ADS

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B In is an effective system to help pilots see and avoid other aircraft. If your aircraft is equipped

with ADS

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B In, it is important to understand its features and how to use it properly. Many units provide visual

and/or audio alerts to supplement the system’s traffic display. Pilots should incorporate the traffic display in their
normal traffic scan to provide awareness of nearby aircraft. Prior to entering or crossing any runway, ADS

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B

In can provide advance indication of arriving aircraft and aircraft in the traffic pattern. Systems that incorporate
a traffic

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alerting feature can help minimize the pilot’s inclination to fixate on the display. Refer to 4

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5

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7e,

ADS

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B Limitations.

(b)

Understand the limitations of ADS

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B In. In certain airspace, not all aircraft will be equipped with

ADS

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B Out or transponders and will not be visible on your ADS

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B In display.

(c)

Limit the amount of time that you focus on flight instruments or tablets.

(d)

Develop a strategic approach to scanning for traffic. Scan the entire sky and try not to focus straight

ahead.

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16. Traffic Alert and Collision Avoidance System (TCAS I & II)

a. TCAS I

 provides proximity warning only, to assist the pilot in the visual acquisition of intruder aircraft.

No recommended avoidance maneuvers are provided nor authorized as a direct result of a TCAS I warning. It
is intended for use by smaller commuter aircraft holding 10 to 30 passenger seats, and general aviation aircraft.

b. TCAS II

 provides traffic advisories (TA) and resolution advisories (RA). Resolution advisories provide

recommended maneuvers in a vertical direction (climb or descend only) to avoid conflicting traffic. Transport
category aircraft, and larger commuter and business aircraft holding 31 passenger seats or more, are required to
be TCAS II equipped.

1.

When a TA occurs, attempt to establish visual contact with the traffic but do not deviate from an assigned

clearance based only on TA information.

2.

When an RA occurs, pilots should respond immediately to the RA displays and maneuver as indicated

unless doing so would jeopardize the safe operation of the flight, or the flight crew can ensure separation with
the help of definitive visual acquisition of the aircraft causing the RA.

3.

Each pilot who deviates from an ATC clearance in response to an RA must notify ATC of that deviation

as soon as practicable, and notify ATC when clear of conflict and returning to their previously assigned clearance.

c.

Deviations from rules, policies, or clearances should be kept to the minimum necessary to satisfy an RA.

Most RA maneuvering requires minimum excursion from assigned altitude.

d.

The serving IFR air traffic facility is not responsible to provide approved standard IFR separation to an IFR

aircraft, from other aircraft, terrain, or obstructions after an RA maneuver until one of the following conditions
exists: