TPM Review – COM

TPM Review – COM

61ST ANNUAL CONFERENCE, 23-27 May 2022

WP No. 62

TPM Review – COM

Presented by TOC



Over the past few years, TOC came to the conclusion that the TPM was in need of a significant overhaul in order to ensure consistency throughout the manual and with ICAO. Every year, several slight changes are made to individual policies, but there is a need to look at the entire TPM in a holistic way.


1.1. The Communications section of the Technical Professional Manual (TPM) consists of several policies, some of which require rather minor adjustments for harmonization whilst others require a more in-depth review.


2.1. COM 4.1 – Alpha-Numeric Callsigns.

2.1.1. It is proposed the first paragraph of the policy stating the definition of alpha-numeric call signs is moved to the Acronyms and Terms section of the TPM:

IFATCA TPM (2019), COM 4.1 – Alpha-Numeric Callsigns

An alpha-numeric call sign is defined as:

An alpha numeric call sign is one where the suffix consists of:

  • number(s) followed by one or more letters; or
  • number(s) followed by a combination of letters and numbers.


2.1.2. It is proposed to change the wording of the first bullet to clarify its intent. As it currently reads, it appears to ban all letters which appear in any airport designators, which of course is incorrect. The original intent of the policy was to avoid letters which appeared in the airport designators of either the point of origin or the destination of the flight. For example: two flights to LAX being named for example KLM60LA and KAL11LA. Therefore, the following new wording is proposed:

IFATCA TPM (2019), COM 4.1 – Alpha-Numeric Callsigns

To reduce the possibility of call sign confusion:

  • Call signs that correspond to the last two designators of both ICAO and/or IATA airport designators of either the point of origin or destination of the flight, shall not be used.
  • […]


2.2. COM 4.2 – Traffic Information Broadcast by Aircraft.

2.2.1. This policy was first adopted by IFATCA in 1991 in Port of Spain and later amended in 1997 in Taipei. It is worth considering whether the issues it addresses are still a point of concern for IFATCA today, or if the policy’s continued provisional status is in fact an indicator that the need has not been felt to make this a full policy. To keep the TPM an orderly and useful document, policies that have no use should be removed to combat unnecessary bloating of the TPM. ICAO has documentation on the use of TIBA and the authors question if having a policy on this matter is within IFATCA’s scope. The review team has determined this policy to be unnecessary and it is therefore recommended for deletion:

IFATCA TPM (2019), COM 4.2 – Traffic Information Broadcast by Aircraft

State Authorities should be required to give adequate notification of the introduction of Traffic Information Broadcasts (TIBA) procedures, i.e. at least 3 months in advance, except where catastrophic events preclude this notification.

TIBA procedures should only be introduced where there are significant technical and/or practical deficiencies in the ATC infrastructure, subject to the Authorities providing adequate procedures and for a limited duration only, not exceeding 6 months.


2.3. COM 4.3 – 8.33 kHz Spacing.

2.3.1. The current policy appears to be outdated and heavily Eurocentric. 8.33 kHz channel spacing has been implemented safely and efficiently in Europe and there appear to be no major problems regarding equipage in the region. However, worldwide implementation has not yet been achieved. Therefore, all references to the EUR ICAO region are removed from this policy.

2.3.2. The latter part of the policy concerning phraseology has either become outdated or become part of ICAO documentation and is therefore proposed for deletion in its entirety (ICAO Annex 10 Vol. II – Aeronautical Communications (2016), Chapter Calling). Various small editorial changes have also been made:

2.3.3. The new policy will read as follows:

IFATCA TPM (2019), COM 4.3 – 8.33 kHz Spacing

The implementation of 8.33 kHz channel spacing should not take place until the speech quality has been tested in a realistic operational environment to ensure that flight safety will not be jeopardised.

To limit controller workload, the procedures and equipment to identify non-equipped aircraft and to deal with the mixed operational environment must shall be in place before 8.33 kHz spacing is introduced. This applies in both the core area of Europe and also in those states that must identify and re-route non-equipped aircraft.

Although it is recognised that 100% equipage will not be achieved and in line with the Safety Validation Groups conclusions based on the assumption of an equipage rate of 95%, IFATCA believes that p Prior to the introduction of 8.33 kHz the following conditions must shall be met:

  • Appropriate “filtering / gate keeping” procedures must shall be in place in the ECAC area and surrounding states. when appropriate.
  • Detection of 8.33 KHz equipage carriage by IFPS and the display of non-equipped status to the controller must shall be in place.
  • Education programmes for pilots and controllers must  shall be completed. This is particularly important in states surrounding 8.33 kHz airspace which will perform the “filtering / gate keeping” procedures.
  • Procedures which consider a controller as the principle means of mitigation are unacceptable.
  • Last minute diversions and sub-versions of non-equipped aircraft directly affect the capacity of the sectors involved therefore such re-routings must shall be kept at  to the absolute minima in order that the safe operations of the sectors involved are not degraded.
  • CFMU shall not re-route automatically non-equipped aircraft into 8.33 kHz sectors.
  • Non-equipped aircraft shall not be automatically re-routed into 8.33 kHz sectors.
  • 121.5 cannot  shall not be considered as a contingency frequency for nonequipped aircraft nor can it be used to re-route or divert aircraft that are not equipped.
  • A 25 kHz independent contingency frequency must shall be available to re-route non- equipped aircraft.
  • Non-equipped medical flights will shall only be accommodated in the case of an inflight emergency.
  • The introduction and use of 8.33 kHz spacing must shall be proven to meet at least the current pre-existing target levels of safety (As for 25 kHz spacings).

The use of the word “channel” by ATC should not be removed from radio telephony without an independent safety review. However, in readback, the pilot may omit the word “channel”.

The use of the word “decimal” should be retained in transmission of frequencies and channels.

Six digits shall only be used in transmitting an 8.33 kHz spaced channel.


2.4. COM 4.4 – Communications Failure.

2.4.1. The first section of the policy states a definition, as it acknowledges. Therefore, it is proposed that this section is moved to the Acronyms and Terms section of the TPM.

2.4.2. The second part of the policy requires a minor grammatical change. The modification would be also to keep in tune with the ICAO harmonization throughout the TPM and would change the wording to: “There shall be one unified global set of procedures for communications failure.”:

IFATCA TPM (2019), COM 4.4 – Communications Failure

The definition of a communication failure is:

A communication failure is a breakdown or unintentional downgrade in the designated means of air-ground communication required for ATS.


There is shall be one unified global set of procedures for communication failure.


2.5. COM 4.5 – RTF Frequency Usage.

2.5.1. Throughout the policy where the word “must” is used it is proposed to change all instances of “must” to “shall” for ICAO harmonization purposes.

2.5.2. An editorial change is needed in the first bullet of the list. The word “problem” can be removed as it is redundant following the “etc.”.

IFATCA TPM (2019), COM 4.5– RTF Frequency Usage

If a controller is providing ATS for two or more areas, the relevant channels must shall be located on the Controller Working Position being used.

If more than one RTF channel is being used, then suitable ‘retransmit’ facilities must shall be provided to enable all users to receive all transmissions. The ability to enable or disable ‘retransmit’ facilities should be provided.

Future systems should include technology that warns the controller in the event of a crossed transmission.

Independent backup equipment should be provided.

Communications with aircraft should only be undertaken within the Designated Operational Coverage (DOC) for the frequency being used.

Voice switch systems must shall include facilities to:

  • mute individual frequencies (due to open microphone, etc. problems) which will also cancel the retransmit for that frequency;
  • present equipment failure alarms and provide the ability to isolate equipment which has failed;
  • select secondary equipment (i.e. receivers, transmitters and paths) at the Controller Working Position;
  • indicate the frequency on which the last incoming call was made.


2.6. COM 4.7 – Direct Pilot-Controller Communications.

2.6.1. The first paragraph presents a lot of clutter and difficult sentence constructions. To ease the reading, it is proposed to amend it as follows:

IFATCA TPM (2019), COM 4.7 – Direct Pilot-Controller Communications

In any ATS system, where data link is considered a safety-critical element of that system, data link based ATS must shall be accompanied by direct two-way controller-pilot voice communications which is also safety critical. This direct voice functionality shall be rapid, continuous and static free.


2.6.2. For purposes of harmonisation in the second paragraph we replace “must” with “shall” as follows:

IFATCA TPM (2019), COM 4.7 – Direct Pilot-Controller Communications

Direct voice communications requires that no third human party is involved in the set-up and / or delivery of these communications. Any set-up procedures by either pilot or controller must shall be minimal and nearly instantaneous.


2.6.3. The third paragraph of this policy looks cumbersome and does not read very well. The wording could be simpler and clearer. It is proposed to reword the third paragraph as follows:

IFATCA TPM (2019), COM 4.7 – Direct Pilot-Controller Communications

For digital air-ground datalink communications to be considered to be direct controllerpilot communications, they shall have demonstrated that they support communications dialogues that provide equivalent VHF voice characteristics in terms of the transactions times, the interface which the human uses to interact with the system, and in terms of the cognitive interface between human and system equivalent to the VHF in terms of transaction times and HMI.


This keeps the spirit and intent of the policy intact while making it more easily understood.

2.7. COM 4.8 – CPDLC – Datalink Communications.

2.7.1. At time of writing, ATN does not appear to be on its way to becoming the global standard for CPDLC. This makes the first three paragraphs of this policy provisional at best and surplus to requirement at worst. The review team believes that the intent of the policy is conveyed in the final paragraph and that the first three are no longer exact, nor necessary. They are therefore recommended for deletion. The remaining policy can be viewed below.

IFATCA TPM (2019), COM 4.8 – CPDLC – Datalink Communications

All implementations of CPDLC must demonstrate full compliance with ICAO ATN SARPs. However, in Oceanic and Remote Regions, where it can be demonstrated that CPDLC implementation improves controller pilot communications, it is recognized that non ATN compliant technologies may be deployed during a transitional phase.

The ICAO ATN SARPs and their progressive development form the definitive basis for any future CPDLC implementation.

In high density ATN CPDLC airspace, FANS aircraft shall be handled via voice R/T for safety reasons.

IFATCA supports efforts to define global safety and performance requirements for data link services in order to:

  • achieve harmonization;
  • support further implementation to improve safety and efficiency.


2.8. COM 4.9 – RTF Phraseology in Civil/Military Integration.

2.8.1. While the goal is ICAO phraseology harmonization, there are times that require variation from this, and in those cases the phraseology should still be the norm, but this difference must be recognized. Therefore, it is suggested to take the existing policy and amend it to read:

IFATCA TPM (2019), COM 4.9 – RTF Phraseology in Civil/Military Integration

When military aircraft operate as General Air Traffic (GAT), civil standard ATC should expect the military pilot to use standard ICAO phraseology should be the norm.

Where controllers are expected to handle military aircraft on a regular basis, they should be made aware of the differences between ICAO and military phraseology military phraseology differing from ICAO standards.


2.9. COM 4.10 – Communications Between ATS Units.

2.9.1. The current Policy is very vague to say the least and does not prescribe a Policy but rather a mere statement of fact. It is suggested to keep the intent and spirit of the policy but to try to make it more substantial.

2.9.2. The suggested new wording for the policy is as follows:

IFATCA TPM (2019), COM 4.10 – Communications Between ATS Units

Ground-to-ground communication is as important as air-to-ground communication. critical to safety and efficiency in aviation as air-to-ground communication. All efforts shall be made to facilitate the prompt and exact exchange of all necessary information for the safe execution of flights.



3.1. There are many policies in need of review which ranges from minor edits to moving to full overhaul. There are several policies that would benefit as well from full policy reviews.


4.1. It is recommended that the abovementioned sections of the Technical and Professional Manual (TPM) be amended accordingly, as described in Section 2 of this working paper.


IFATCA. (2019). IFATCA Technical and Professional Manual (TPM). 2019 Ed. Montréal, Canada: International Federation of Air Traffic Controllers’ Associations.


Last Update: July 26, 2022  

July 20, 2022   141   Jean-Francois Lepage    2022    

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