AIM 5-5-9

Pilot. 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.

Complies with speed adjustments from ATC unless: The minimum or maximum safe airspeed for any particular operation is greater or less than the requested airspeed. In such cases, advises ATC. NOTE-

It is the pilot's responsibility and prerogative to refuse speed adjustments considered excessive or contrary to the aircraft's operating specifications.

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).

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.

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

Adheres to the restrictions published in FAA Order JO 7110.65, Air Traffic Control, as to when speed adjustment procedures may be applied.

Avoids speed adjustments requiring alternate decreases and increases.

Assigns speed adjustments to a specified IAS (KNOTS)/Mach number or to increase or decrease speed using increments of 5 knots or multiples thereof.

Terminates ATC-assigned speed adjustments when no longer required by issuing further instructions to pilots in the following manner: Advises pilots to “resume normal speed” when the aircraft is on a heading, random routing, charted procedure, or route without published speed restrictions.

Instructs pilots to “comply with speed restrictions” when the aircraft is joining or resuming a charted procedure or route with published speed restrictions. NOTE-

The phraseology “Climb via SID” requires compliance with all altitude and/or speed restrictions depicted on the procedure.

Instructs pilots to “resume published speed” when aircraft are cleared via a charted instrument flight procedure that contains published speed restrictions.

Advises aircraft to “delete speed restrictions” when ATC assigned or published speed restrictions on a charted procedure are no longer required.

Clears pilots for approach without restating previously issued speed adjustments. REFERENCE-

Pilot/Controller Glossary Term - Resume Normal Speed.

Pilot/Controller Glossary Term - Resume Published Speed.

Gives due consideration to aircraft capabilities to reduce speed while descending.

Does not assign speed adjustments to aircraft at or above FL 390 without pilot consent.