Aeronautical Information Manual (AIM), page 404

Index   403 -- Page 404 -- 405


2. Be aware that this service is not always
available and that many factors affect the ability of
the controller to be aware of a situation in which
unsafe proximity to terrain, obstructions, or another
aircraft may be developing.
b. Controller.

1. Issues a safety alert if aware an aircraft under
their control is at an altitude which, in the controller's
judgment, places the aircraft in unsafe proximity to
terrain, obstructions or another aircraft. Types of
safety alerts are:

(a) Terrain or Obstruction Alert. Immedi-
ately issued to an aircraft under their control if aware
the aircraft is at an altitude believed to place the
aircraft in unsafe proximity to terrain or obstructions.

(b) Aircraft Conflict Alert. Immediately
issued to an aircraft under their control if aware of an
aircraft not under their control at an altitude believed
to place the aircraft in unsafe proximity to each other.
With the alert, they offer the pilot an alternative, if

2. Discontinue further alerts if informed by the
pilot action is being taken to correct the situation or

that the other aircraft is in sight.

5-5-8. See and Avoid

a. Pilot. When meteorological conditions permit,
regardless of type of flight plan or whether or not
under control of a radar facility, the pilot is
responsible to see and avoid other traffic, terrain, or
b. Controller.
1. Provides radar traffic information to radar
identified aircraft operating outside positive control
airspace on a workload permitting basis.
2. Issues safety alerts to aircraft under their
control if aware the aircraft is at an altitude believed
to place the aircraft in unsafe proximity to terrain,
obstructions, or other aircraft.

5-5-9. Speed Adjustments

a. Pilot.

1. Advises ATC any time cruising airspeed
varies plus or minus 5 percent or 10 knots, whichever
is greater, from that given in the flight plan.


2. Complies with speed adjustments from ATC
(a) The minimum or maximum safe airspeed
for any particular operation is greater or less than the
requested airspeed. In such cases, advises ATC.
It is the pilot's responsibility and prerogative to refuse
speed adjustments considered excessive or contrary to the
aircraft's operating specifications.

(b) Operating at or above 10,000 feet MSL on
an ATC assigned SPEED ADJUSTMENT of more
than 250 knots IAS and subsequent clearance is
received for descent below 10,000 feet MSL. In such
cases, pilots are expected to comply with 14 CFR
Section 91.117(a).

3. When complying with speed adjustment
assignments, maintains an indicated airspeed within
plus or minus 10 knots or 0.02 Mach number of the
specified speed.
b. Controller.

1. Assigns speed adjustments to aircraft when
necessary but not as a substitute for good vectoring

2. Adheres to the restrictions published in FAA

Order JO 7110.65, Air Traffic Control, as to when
speed adjustment procedures may be applied.

3. Avoids speed adjustments requiring alternate
decreases and increases.
4. Assigns speed adjustments to a specified IAS
(KNOTS)/Mach number or to increase or decrease
speed using increments of 5 knots or multiples
5. Terminates ATC-assigned speed adjustments
when no longer required by issuing further
instructions to pilots in the following manner:
(a) Advises pilots to "resume normal speed"
when the aircraft is on a heading, random routing,
charted procedure, or route without published speed
(b) Instructs pilots to "comply with speed
restrictions" when the aircraft is joining or resuming
a charted procedure or route with published speed

The phraseology "comply with restrictions" requires
compliance with all altitude and/or speed restrictions
depicted on the procedure.

5-5-4 Pilot/Controller Roles and Responsibilities

Page 404 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures

Index   403 -- Page 404 -- 405