32ND ANNUAL CONFERENCE, Christchurch, NZ, 19-23 April 1993
WP No. 89
RNAV Procedural Separation – Amendment of Current Policy
The current Policy Statement 7.6 – RNAV Procedural Separation Minima – is operationally unrealistic in terms of existing longitudinal separation practice. It is unrealistic because it advocates a minimum time standard that in fact has already been superseded by common accepted operational practice i.e. a minimum of 5 minutes longitudinal time separation when Mach No. Technique is used.
The existing policy is not definite because it deals with two different types of longitudinal separation. Longitudinal time separation is different both in principle and in application when compared to longitudinal distance separations. In the not too distant future with the introduction of ADS and datalinking there will be further changes to the standards and application of longitudinal separations. It is therefore appropriate to anticipate this and make two separate policy statements because the two basic forms of longitudinal separation will most likely be affected to differing degrees by the new technology.
IFATCA policy should be both proactive and operationally practical.
The existing policy for longitudinal separations combines both time and distance standards.
Longitudinal separations of less than 10 minutes are currently being used with the application of Mach No. Technique (MNT) between suitably equipped RNAV aircraft.
The existing policy is unenforceable, imprecise and redundant.
The existing 7.6 IFATCA Policy Statement “RNAV Procedural Separation” should be deleted and replaced by two new policy statements.
A new IFATCA policy statement for RNAV procedural distance separation is produced in a separate working paper.
SC 1 does not support any reduction of the present minimum longitudinal time standard of 5 Minutes based on the use of the Mach No. technique.
It is recommended that:
That the existing 7.6 policy statement be deleted.
Any reduction below the present minimum longitudinal standard of 5 minutes based on mach No. Technique will not be considered.
Last Update: September 20, 2020