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AIM

10/12/17

4−4−11

ATC Clearances and Aircraft Separation

Although many pilots seem to prefer the method of

horizontal back−and−forth scanning every pilot

should develop a scanning pattern that is not only

comfortable but assures optimum effectiveness.

Pilots should remember, however, that they have a

regulatory responsibility (14 CFR Section 91.113(a))

to see and avoid other aircraft when weather

conditions permit.

4−4−15. Use of Visual Clearing Procedures

a. Before Takeoff. Prior to taxiing onto a runway

or landing area in preparation for takeoff, pilots

should scan the approach areas for possible landing

traffic and execute the appropriate clearing maneu-

vers to provide them a clear view of the approach

areas.

b. Climbs and Descents. During climbs and

descents in flight conditions which permit visual

detection of other traffic, pilots should execute gentle

banks, left and right at a frequency which permits

continuous visual scanning of the airspace about

them.

c. Straight and Level. Sustained periods of

straight and level flight in conditions which permit

visual detection of other traffic should be broken at

intervals with appropriate clearing procedures to

provide effective visual scanning.

d. Traffic Pattern. Entries into traffic patterns

while descending create specific collision hazards

and should be avoided.

e. Traffic at VOR Sites. All operators should

emphasize the need for sustained vigilance in the

vicinity of VORs and airway intersections due to the

convergence of traffic.

f. Training Operations. Operators of pilot train-

ing programs are urged to adopt the following

practices:

1. Pilots undergoing flight instruction at all

levels should be requested to verbalize clearing

procedures (call out “clear” left, right, above, or

below) to instill and sustain the habit of vigilance

during maneuvering.

2. High−wing airplane. Momentarily raise the

wing in the direction of the intended turn and look.

3. Low−wing airplane. Momentarily lower

the wing in the direction of the intended turn and look.

4. Appropriate clearing procedures should

precede the execution of all turns including

chandelles, lazy eights, stalls, slow flight, climbs,

straight and level, spins, and other combination

maneuvers.

4−4−16. 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:

1. The aircraft has returned to its assigned

altitude and course.

2/28/19

AIM