COM 4.3 8.33 kHz SPACING

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COM 4.3 8.33 kHz SPACING

The introduction of 8.33 kHz will have a major impact on the European ATC system. The quality of 8.33 kHz spacing appears to be unproven. It would appear that no realistic operational trials have been done. There is the possibility of non-equipped aircraft entering 8.33 kHz, with the increased possibility of frequency blocking, and the additional workload placed on controllers both around and below the 8.33 kHz airspace. The identification and control of non-equipped aircraft relies on the flight planning arrangements working reliably and these systems need to be in place and properly tested before 8.33 kHz spacing is introduced.

All these factors may potentially have an adverse impact on the safety of the ATC system.

IFATCA Policy is:

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 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.

See: WP 87 – Taipei 1997

IFATCA Policy is:

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 prior to the introduction of 8.33 kHz the following conditions must be met:

  • Appropriate “filtering / gate keeping” procedures must be in place in the ECAC area and surrounding states.
  • Detection of 8.33 KHz carriage by IFPS and the display of non-equipped status to the controller must be in place.
  • Education programmes for pilots and controllers must 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 be kept at 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.
  • 5 cannot be considered as a contingency frequency for non equipped aircraft nor can it be used to re-route or divert aircraft that are not equipped.
  • A 25 kHz independent contingency frequency must be available to re-route non- equipped aircraft.
  • Non-equipped medical flights will only be accommodated in the case of an in flight emergency.
  • The introduction and use of 8.33 kHz spacing must be proven to meet at least the current target levels of safety (As for 25 kHz spacings).

See: WP 99 – Santiago 1999

IFATCA Policy is:

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.

See: WP 86 – Cancun 2002


Last Update: September 29, 2020  

November 5, 2019   266   Jean-Francois Lepage    COM    

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