ESTABLISHMENT AND CONTINUATION OF COMMUNICATION

When establishing communications, an aircraft should use the full call sign of both the aircraft and the aeronautical station.

When a ground station wishes to broadcast information, the message should be prefaced by the call “ALL STATIONS”.

When an aircraft wishes to broadcast information to aircraft in its vicinity, the message should be prefaced by the call “ALL STATIONS”.

No reply is expected to such general calls unless individual stations are subsequently called upon to acknowledge receipt.

If there is doubt that a message has been correctly received, a repetition of the message shall be requested either in full or in part.

Phrase Meaning

SAY AGAIN Repeat entire message

SAY AGAIN ... (item) Repeat specific item

SAY AGAIN ALL BEFORE ... Repeat part of message

SAY AGAIN ALL AFTER ... Repeat part of message

SAY AGAIN ALL BETWEEN ... AND ... Repeat part of message

When a station is called but uncertain of the identity of the calling station, the calling station should be requested to repeat its call sign until the identity is established.

When an error is made in a transmission, the word “CORRECTION” shall be spoken, the last correct group or phrase repeated and then the correct version transmitted.

If a correction can best be made by repeating the entire message, the operator shall use the phrase “CORRECTION I SAY AGAIN” before transmitting the message a second time.

When it is considered that reception is likely to be difficult, important elements of the message should be spoken twice.

TRANSFER OF COMMUNICATION

An aircraft shall be advised by the appropriate aeronautical station to change from one radio frequency to another in accordance with agreed procedures. In the absence of such advice, the aircraft shall notify the aeronautical station before such a change takes place

or,

An aircraft may be instructed to “stand by” on a frequency when it is intended that the ATS unit will initiate communications soon, and to “monitor” a frequency on which information is being broadcast.

ISSUE OF CLEARANCE AND READ-BACK REQUIREMENTS

Controllers should pass a clearance slowly and clearly since the pilot needs to write it down and wasteful repetition will thus be avoided. Whenever possible, a route clearance should be passed to an aircraft before start up. In any case, controllers should avoid passing a clearance to a pilot engaged in complicated taxiing manoeuvres and on no occasion should a clearance be passed when the pilot is engaged in line up or take-off manoeuvres.

An air traffic control (ATC) route clearance is not an instruction to take off or enter an active runway. The words “TAKE OFF” are used only when an aircraft is cleared for take-off, or when cancelling a take-off clearance. At other times, the word “DEPARTURE” or “AIRBORNE” is used.

Read-back requirements have been introduced in the interests of flight safety. The stringency of the read-back requirement is directly related to the possible seriousness of a misunderstanding in the transmission and receipt of ATC clearances and instructions. Strict adherence to read-back procedures ensures not only that the clearance has been received correctly but also that the clearance was transmitted as intended. It also serves as a check that the right aircraft, and only that aircraft, will take action on the clearance.

The following shall always be read back:

1. ATC route clearances;

2. clearances and instructions to enter, land on, take off from, hold short of, cross and backtrack on any runway; and

3. runway-in-use, altimeter settings, SSR codes, level instructions, heading and speed instructions and, whether issued by the controller or contained in ATIS broadcasts, transition levels.

Other clearances or instructions, including conditional clearances, shall be read back or acknowledged in a manner to clearly indicate that they have been understood and will be complied with.

An aircraft should terminate the read-back by its call sign.

Or,

The controller shall listen to the read-back to ascertain that the clearance or instruction has been correctly acknowledged by the flight crew and shall take immediate action to correct any discrepancies revealed by the read-back.

If an aircraft read-back of a clearance or instruction is incorrect, the controller shall transmit the word “NEGATIVE I SAY AGAIN” followed by the correct version.

If there is a doubt as to whether a pilot can comply with an ATC clearance or instruction, the controller may follow the clearance or instruction by the phrase “if unable”, and subsequently offer an alternative. If at any time a pilot receives a clearance or instruction which cannot be complied with, that pilot should advise the controller using the phrase “UNABLE” and give the reasons.

TEST PROCEDURES

Test transmissions should take the following form:

Replies to test transmissions should be as follows:

The readability of transmissions should be classified in accordance with the following readability scale:

1. Unreadable.

2. Readable now and then.

3. Readable but with difficulty.

4. Readable.

5. Perfectly readable.