Coordination

Estimates and Revisions

ATC Coordination for Exchange of Estimate Information:

• ESTIMATE [direction of flight] (aircraft call sign) [SQUAWKING (SSR code)] (type) ESTIMATED (significant point) (time) (level) (or DESCENDING FROM (level) TO (level)) [SPEED (filed TAS)] (route) [REMARKS]
• ESTIMATE (significant point) ON (aircraft call sign)

ATC Instructions for Receiving Unit Reply When Flight Plan Details Are Not Available:

• NO DETAILS

ATC Instructions for Receiving Unit Reply When Flight Plan Details Are Available:

• (aircraft type) (destination) Instruction sending unit reply [SQUAWKING (SSR code)] [ESTIMATED] (significant point) (time) AT (level)

ATC Estimate for Unmanned Free Balloon(s):

• ESTIMATE UNMANNED FREE BALLOON(S) (identification and classification) ESTIMATED OVER (place) AT (time) REPORTED FLIGHT LEVEL(S) (figure or figures) [or FLIGHT LEVEL UNKNOWN] MOVING (direction) ESTIMATED GROUND SPEED (figure) (other pertinent information, if any)

ATC Revision to an Estimate:

• REVISION (aircraft call sign) (details as necessary)

Transfer of Control

ATC Instructions for Handing Over an Aircraft to Another ATC Unit:

• REQUEST RELEASE OF (aircraft call sign)
• (aircraft call sign) RELEASED [AT (time)] [conditions/restrictions]
• IS (aircraft call sign) RELEASED [FOR CLIMB (or DESCENT)]
• (aircraft call sign) NOT RELEASED [UNTIL (time or significant point)]
• UNABLE (aircraft call sign) [TRAFFIC IS (details)]

Change of Clearance

ATC Request to Modify a Clearance:

• MAY WE CHANGE CLEARANCE OF (aircraft call sign) TO (details of alteration proposed)

ATC Coordination for Clearance Agreement:

• AGREED TO (alteration of clearance) OF (aircraft call sign)

ATC Response When Clearance Change Is Not Possible:

• UNABLE (aircraft call sign)
• UNABLE (desired route, level, etc.) [FOR (aircraft call sign)] [DUE (reason)] (alternative clearance proposed)

Approval Request

ATC Request for Approval of an Aircraft Departure:

• APPROVAL REQUEST (aircraft call sign) ESTIMATED DEPARTURE FROM (significant point) AT (time)

ATC Response to Approval Request:

• (aircraft call sign) REQUEST APPROVED [(restriction if any)]
• (aircraft call sign) UNABLE (alternative instructions)

Inbound Release

ATC Definition of Release Point During Handover Procedure:

• [INBOUND RELEASE] (aircraft call sign) [SQUAWKING (SSR code)] (type) FROM (departure point) RELEASED AT (significant point, or time, or level) CLEARED TO AND ESTIMATING (clearance limit) (time) AT (level) [EXPECTED APPROACH TIME or NO DELAY EXPECTED] CONTACT AT (time)

Handover

ATC Request for a Handover Procedure:

• HANDOVER (aircraft call sign) [SQUAWKING (SSR code)] POSITION (aircraft position) (level)

Expedition of Clearance

ATC Request for Expedited Clearance:

• EXPEDITE CLEARANCE (aircraft call sign) EXPECTED DEPARTURE FROM (place) AT (time)
• EXPEDITE CLEARANCE (aircraft call sign) [ESTIMATED] OVER (place) AT (time) REQUESTS (level or route, etc.)

Reduced Vertical Separation (RVSM)

ATC Communication Stating an Aircraft Is Unable to Perform RVSM:

• NEGATIVE RVSM [(supplementary information, e.g. State aircraft)]

ATC Communication Stating an Aircraft Cannot Conduct RVSM Due to Turbulence, Equipment Failure, or Severe Meteorological Phenomena:

• UNABLE RVSM DUE TURBULENCE (or EQUIPMENT, as applicable)