ICAO CIRCULAR 319 PDF

INTRODUCTION

The collision risk models (CRMs) covered in this circular are those presented in the Manual on Airspace Planning Methodology for the Determination of Separation Minima (Doc 9689) and the Manual on Implementation of a 300 m (1000 ft) Vertical Separation Minimum Between FL 290 and FL 410 Inclusive (Doc 9574). This circular introduces a unified framework which enables an analytical derivation of all these collision risk models. The reason why it is possible to derive them under the same framework is that these CRMs share similar modelling assumptions.

Chapter 2 introduces the appropriate nomenclature. Chapter 3 reviews the modelling of the uncertainty associated with aircraft location and examines some extensions to current CRMs. It appears that, from a controller's viewpoint, the modelling of uncertainties described in Chapter 3 is inadequate in environments with a high update rate of aircraft positions. Actually, all CRMs presented in Docs 9689 and 9574 apply to environments with a low update rate. Possible methods for modelling uncertainties in environments with a high update rate are suggested in Chapter3, 3.6.

Chapter 4 introduces a key formula, called the Rice Formula, which plays a major part in the derivation of CRMs. Derivation of CRMs using the Rice Formula is presented in Chapters 5 to 7.

Chapter 8 and 9 present a generic CRM which applies to any operational scenario involving a pair of aircraft, either for same/opposite directions (Chapter 8) or for crossing routes (Chapter 9). Since this CRM is particularly interesting for the risk assessment of predetermined operational hazards, it is presented in a more general form first, followed by an important application of this CRM in an ADS-C environment.

Finally, Chapter 10 provides a list of recommended reading and reference material.